Reply
Page 1 of 16 1 2 3 11 ... LastLast
Results 1 to 30 of 461
  1. #1
    Up And Out cakedonkey's Avatar
    Join Date: Sep 2004
    Location: Massachusetts, United States
    Posts: 6,849
    Rep Power: 3502
    cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500)
    cakedonkey is offline

    Exclamation Oral Glutamine Does NOTHING For Athletic Performance

    1: Appl Physiol Nutr Metab. 2006 Oct;31(5):518-29.

    Addition of glutamine to essential amino acids and carbohydrate does not enhance anabolism in young human males following exercise.

    Wilkinson SB, Kim PL, Armstrong D, Phillips SM.

    Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada.

    We examined the effect of a post-exercise oral carbohydrate (CHO, 1 g.kg(-1).h(-1)) and essential amino acid (EAA, 9.25 g) solution containing glutamine (0.3 g/kg BW; GLN trial) versus an isoenergetic CHO-EAA solution without glutamine (control, CON trial) on muscle glycogen resynthesis and whole-body protein turnover following 90 min of cycling at 65% VO2 peak. Over the course of 3 h of recovery, muscle biopsies were taken to measure glycogen resynthesis and mixed muscle protein synthesis (MPS), by incorporation of [ring-2H5] phenylalanine. Infusion of [1-13C] leucine was used to measure whole-body protein turnover. Exercise resulted in a significant decrease in muscle glycogen (p < 0.05) with similar declines in each trial. Glycogen resynthesis following 3 h of recovery indicated no difference in total accumulation or rate of repletion. Leucine oxidation increased 2.5 fold (p < 0.05) during exercise, returned to resting levels immediately post-exercise,and was again elevated at 3 h post-exercise (p < 0.05). Leucine flux, an index of whole-body protein breakdown rate, was reduced during exercise, but increased to resting levels immediately post-exercise, and was further increased at 3 h post-exercise (p < 0.05), but only during the CON trial. Exercise resulted in a marked suppression of whole-body protein synthesis (50% of rest; p < 0.05), which was restored post-exercise; however, the addition of glutamine did not affect whole-body protein synthesis post-exercise. The rate of MPS was not different between trials. The addition of glutamine to a CHO + EAA beverage had no effect on post-exercise muscle glycogen resynthesis or muscle protein synthesis, but may suppress a rise in whole-body proteolysis during the later stages of recovery.

    PMID: 17111006 [PubMed - indexed for MEDLINE]


    1: Eur J Appl Physiol. 2001 Dec;86(2):142-9.

    Effect of glutamine supplementation combined with resistance training in young adults.

    Candow DG, Chilibeck PD, Burke DG, Davison KS, Smith-Palmer T.

    College of Kinesiology, University of Saskatchewan, Saskatoon, Canada.

    The purpose of this study was to assess the effect of oral glutamine supplementation combined with resistance training in young adults. A group of 31 subjects, aged 18-24 years, were randomly allocated to groups (double blind) to receive either glutamine (0.9 g x kg lean tissue mass(-1) x day(-1); n = 17) or a placebo (0.9 g maltodextrin x kg lean tissue mass(-1) x day(-1); n = 14 during 6 weeks of total body resistance training. Exercises were performed for four to five sets of 6-12 repetitions at intensities ranging from 60% to 90% 1 repetition maximum (1 RM). Before and after training, measurements were taken of 1 RM squat and bench press strength, peak knee extension torque (using an isokinetic dynamometer), lean tissue mass (dual energy X-ray absorptiometry) and muscle protein degradation (urinary 3-methylhistidine by high performance liquid chromatography). Repeated measures ANOVA showed that strength, torque, lean tissue mass and 3-methylhistidine increased with training (P < 0.05), with no significant difference between groups. Both groups increased their 1 RM squat by approximately 30% and 1 RM bench press by approximately 14%. The glutamine group showed increases of 6% for knee extension torque, 2% for lean tissue mass and 41% for urinary levels of 3-methylhistidine. The placebo group increased knee extension torque by 5%, lean tissue mass by 1.7% and 3-methylhistidine by 56%. We conclude that glutamine supplementation during resistance training has no significant effect on muscle performance, body composition or muscle protein degradation in young healthy adults.

    PMID: 11822473 [PubMed - indexed for MEDLINE]


    Facts and fallacies of purported ergogenic amino acid supplements.

    Williams MH.

    Department of Exercise Science, Physical Education, and Recreation, Old Dominion University, Norfolk, Virginia, USA. mwilliam@odu.edu

    Although current research suggests that individuals involved in either high-intensity resistance or endurance exercise may have an increased need for dietary protein, the available research is either equivocal or negative relative to the ergogenic effects of supplementation with individual amino acids. Although some research suggests that the induction of hyperaminoacidemia via intravenous infusion of a balanced amino acid mixture may induce an increased muscle protein synthesis after exercise, no data support the finding that oral supplementation with amino acids, in contrast to dietary protein, as the source of amino acids is more effective. Some well-controlled studies suggest that aspartate salt supplementation may enhance endurance performance, but other studies do not, meriting additional research. Current data, including results for several well-controlled studies, indicated that supplementation with arginine, ornithine, or lysine, either separately or in combination, does not enhance the effect of exercise stimulation on either hGH or various measures of muscular strength or power in experienced weightlifters. Plasma levels of BCAA and tryptophan may play important roles in the cause of central fatigue during exercise, but the effects of BCAA or tryptophan supplementation do not seem to be effective ergogenics for endurance exercise performance, particularly when compared with carbohydrate supplementation, a more natural choice. Although glutamine supplementation may increase plasma glutamine levels, its effect on enhancement of the immune system and prevention of adverse effects of the overtraining syndrome are equivocal. Glycine, a precursor for creatine, does not seem to possess the ergogenic potential of creatine supplementation. Research with metabolic by-products of amino acid metabolism is in its infancy, and current research findings are equivocal relative to ergogenic applications. In general, physically active individuals are advised to obtain necessary amino acids through consumption of natural, high-quality protein foods.

    PMID: 10410846 [PubMed - indexed for MEDLINE]

    Amino acids and endurance exercise.

    Hargreaves MH, Snow R.

    School of Health Sciences, Deakin University, Burwood, 3125, Australia.

    Although skeletal muscle is capable of oxidizing selected amino acids, exercise in the fed and carbohydrate-replete condition results in only a small increase in amino acid utilization. Nevertheless, it may be important to increase the dietary protein requirements of active individuals. There is ongoing debate as to whether the amino acids for oxidation are derived from the free amino acid pool, from net protein breakdown, or a combination of both. There has been interest in the potential ergogenic benefits of amino acid ingestion; however, BCAA ingestion does not appear to affect fatigue during prolonged exercise, there is little support from controlled studies to recommend glutamine ingestion for enhanced immune function, and although glutamine stimulates muscle glycogen synthesis, its addition to carbohydrate supplements provides no additional benefit over ingestion of carbohydrate alone.


    PMID: 11255141 [PubMed - indexed for MEDLINE]
    The Effects of High-Dose Glutamine Ingestion on Weightlifting Performance

    JOSE ANTONIO1, 3, MICHAEL S. SANDERS1, DOUGLAS KALMAN2, DEREK WOODGATE1, and CHRIS STREET1

    1. Sports Science Laboratory, University of Delaware, Newark, Delaware 19716, 2. Peak Wellness, Greenwich, Connecticut 06830, 3. Address correspondence to Jose Antonio, Scientific Affairs Department, Nutricia, 6111 Broken Sound Parkway NW, Boca Raton, FL 33487

    The purpose of this study was to determine if high-dose glutamine ingestion affected weightlifting performance. In a double-blind, placebo-controlled, crossover study, 6 resistance-trained men (mean ? SE: age, 21.5 ? 0.3 years; weight, 76.5 ? 2.8 kg−1) performed weightlifting exercises after the ingestion of glutamine or glycine (0.3 g?kg−1) mixed with calorie-free fruit juice or placebo (calorie-free fruit juice only). Each subject underwent each of the 3 treatments in a randomized order. One hour after ingestion, subjects performed 4 total sets of exercise to momentary muscular failure (2 sets of leg presses at 200% of body weight, 2 sets of bench presses at 100% of body weight). There were no differences in the average number of maximal repetitions performed in the leg press or bench press exercises among the 3 groups. These data indicate that the short-term ingestion of glutamine does not enhance weightlifting performance in resistance-trained men.

    Reference Data:Antonio, J., M.S. Sanders, D. Kalman, D. Woodgate, and C. Street. The effects of high-dose glutamine ingestion on weightlifting performance.

    Keywords: amino acid, supplement, nutrition, protein

    DOI: 10.1519/1533-4287(2002)016[0157:TEOHDG]2.0.CO;2
    Last edited by cakedonkey; 11-16-2007 at 12:19 PM.
    SAN Nutrition
    sann.net / pumpedmag.com / starmarklabs.com
    Reply With Quote

  2. #2
    Up And Out cakedonkey's Avatar
    Join Date: Sep 2004
    Location: Massachusetts, United States
    Posts: 6,849
    Rep Power: 3502
    cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500)
    cakedonkey is offline
    Just wanted to get together some relevant data. Healthy humans, orally adminstered, etc. Either that, or relevant reviews. Indeed, this is a sickeningly re-hashed topic, but I am dumbfounded to see that there are still people embracing glutamine supplemention. Hence, this can serve as yet another thread to refer such confused souls.
    SAN Nutrition
    sann.net / pumpedmag.com / starmarklabs.com
    Reply With Quote

  3. #3
    RELOADING SavageOne's Avatar
    Join Date: Jan 2006
    Location: Lake Mary, Florida, United States
    Age: 36
    Posts: 8,855
    Rep Power: 1497
    SavageOne is just really nice. (+1000) SavageOne is just really nice. (+1000) SavageOne is just really nice. (+1000) SavageOne is just really nice. (+1000) SavageOne is just really nice. (+1000) SavageOne is just really nice. (+1000) SavageOne is just really nice. (+1000) SavageOne is just really nice. (+1000) SavageOne is just really nice. (+1000) SavageOne is just really nice. (+1000) SavageOne is just really nice. (+1000)
    SavageOne is offline
    Great job assembling studies on it. I wish this could be stickied, because it's an issue on a daily basis.
    Reply With Quote

  4. #4
    Surgeon By 2012 or Bust! -Aaron-'s Avatar
    Join Date: Apr 2007
    Posts: 20,559
    Rep Power: 13675
    -Aaron- is a splendid one to behold. (+10000) -Aaron- is a splendid one to behold. (+10000) -Aaron- is a splendid one to behold. (+10000) -Aaron- is a splendid one to behold. (+10000) -Aaron- is a splendid one to behold. (+10000) -Aaron- is a splendid one to behold. (+10000) -Aaron- is a splendid one to behold. (+10000) -Aaron- is a splendid one to behold. (+10000) -Aaron- is a splendid one to behold. (+10000) -Aaron- is a splendid one to behold. (+10000) -Aaron- is a splendid one to behold. (+10000)
    -Aaron- is offline
    Doesn't it aid with digestive support and is a glucose disposal agent?
    "The world will look up and shout save us... And I'll whisper, no."

    Leonidas300, SCDiesel23, Jkeith are my heroes.
    Reply With Quote

  5. #5
    Up And Out cakedonkey's Avatar
    Join Date: Sep 2004
    Location: Massachusetts, United States
    Posts: 6,849
    Rep Power: 3502
    cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500)
    cakedonkey is offline
    Originally Posted by -Aaron- View Post
    Doesn't it aid with digestive support and is a glucose disposal agent?
    Both claims are unsubstantiated in the literature.
    SAN Nutrition
    sann.net / pumpedmag.com / starmarklabs.com
    Reply With Quote

  6. #6
    3D Water Chestnuts NO HYPE's Avatar
    Join Date: Jun 2006
    Posts: 14,979
    Rep Power: 31610
    NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000)
    NO HYPE is offline
    Thanks for the addition to my (already) long list.
    Last edited by NO HYPE; 11-16-2007 at 08:46 PM.
    ~

    Wherever progression lacks.... regress can be found in abundance.
    Reply With Quote

  7. #7
    Actual Pharmacist Bane's Avatar
    Join Date: Oct 2002
    Location: Greece
    Posts: 5,699
    Rep Power: 18112
    Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000)
    Bane is offline
    It is very good for ulcer though, but noone seems to use it for this
    Reply With Quote

  8. #8
    Up And Out cakedonkey's Avatar
    Join Date: Sep 2004
    Location: Massachusetts, United States
    Posts: 6,849
    Rep Power: 3502
    cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500)
    cakedonkey is offline
    Originally Posted by Bane View Post
    It is very good for ulcer though, but noone seems to use it for this

    If I recall, N-acetyl-L-glutamine (NAG) was actually marketed as an anti-ulcer agent in certain countries. Not sure if the same can be said for typical L-glutamine.
    SAN Nutrition
    sann.net / pumpedmag.com / starmarklabs.com
    Reply With Quote

  9. #9
    Actual Pharmacist Bane's Avatar
    Join Date: Oct 2002
    Location: Greece
    Posts: 5,699
    Rep Power: 18112
    Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000)
    Bane is offline
    Originally Posted by cakedonkey View Post
    If I recall, N-acetyl-L-glutamine (NAG) was actually marketed as an anti-ulcer agent in certain countries. Not sure if the same can be said for typical L-glutamine.
    It can. Glutamine provides ready energy for the gut(main reason it is a waste to get it for athletic performance, it doesn't even make it to the blood), reduces gut inflammation and increases gut healing. The studies are out there if you look out a bit
    Reply With Quote

  10. #10
    3D Water Chestnuts NO HYPE's Avatar
    Join Date: Jun 2006
    Posts: 14,979
    Rep Power: 31610
    NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000)
    NO HYPE is offline
    Originally Posted by Bane View Post
    Glutamine provides ready energy for the gut(main reason it is a waste to get it for athletic performance, it doesn't even make it to the blood), reduces gut inflammation and increases gut healing.
    I agree.

    Originally Posted by NO HYPE View Post
    With the exception of supplemental glutamine's beneficial role in gastrointestinal disorders (and general gut health), sepsis, and for the recovery from trauma and or surgery.... there's not much sense in administering a product that is very much limited in it's availability for physiological uptake, due to the fact that it's endogenous levels (prior to supplementation) are double the concentration of any other amino acid within the human body (1).
    Additionally, free form glutamine is unstable in solution at physiological pH.
    ~

    Wherever progression lacks.... regress can be found in abundance.
    Reply With Quote

  11. #11
    3D Water Chestnuts NO HYPE's Avatar
    Join Date: Jun 2006
    Posts: 14,979
    Rep Power: 31610
    NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000)
    NO HYPE is offline
    Originally Posted by Bane View Post
    it doesn't even make it to the blood
    Well not usually in any large amounts however, getting oral glutamine into systemic circulation would entirely depend on plasma availability.
    ~

    Wherever progression lacks.... regress can be found in abundance.
    Reply With Quote

  12. #12
    Actual Pharmacist Bane's Avatar
    Join Date: Oct 2002
    Location: Greece
    Posts: 5,699
    Rep Power: 18112
    Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000)
    Bane is offline
    Originally Posted by NO HYPE View Post
    Well not usually in any large amounts however, getting oral glutamine into systemic circulation would entirely depend on plasma availability.
    No it would mainly depend on how much teh GI tract and the liver need.
    Which is tons.
    Which is why you start seeing "something" from free form glutamine at about 30-40 grams
    Reply With Quote

  13. #13
    3D Water Chestnuts NO HYPE's Avatar
    Join Date: Jun 2006
    Posts: 14,979
    Rep Power: 31610
    NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000)
    NO HYPE is offline
    Originally Posted by NO HYPE View Post
    getting oral glutamine into systemic circulation would entirely depend on plasma availability.
    Originally Posted by Bane View Post
    No it would mainly depend on how much teh GI tract and the liver need. Which is tons.
    Aren't the "tons" in which you speak of, supplied by normal plasma glutamine concentrations? I was under the impression that in times of normal health.... GI enterocytes/liver do not require enough glutamine to significantly deplete plasma concentrations (as opposed to the amounts of glutamine being drawn from the plasma for skeletal muscle activity/repair).
    Last edited by NO HYPE; 11-17-2007 at 04:08 PM.
    ~

    Wherever progression lacks.... regress can be found in abundance.
    Reply With Quote

  14. #14
    nom nom nom deserusan's Avatar
    Join Date: Mar 2004
    Location: New York, United States
    Age: 40
    Posts: 28,169
    Rep Power: 57815
    deserusan has much to be proud of. One of the best! (+20000) deserusan has much to be proud of. One of the best! (+20000) deserusan has much to be proud of. One of the best! (+20000) deserusan has much to be proud of. One of the best! (+20000) deserusan has much to be proud of. One of the best! (+20000) deserusan has much to be proud of. One of the best! (+20000) deserusan has much to be proud of. One of the best! (+20000) deserusan has much to be proud of. One of the best! (+20000) deserusan has much to be proud of. One of the best! (+20000) deserusan has much to be proud of. One of the best! (+20000) deserusan has much to be proud of. One of the best! (+20000)
    deserusan is offline

    Talking Thinking outside of the box helps......

    Glutamine protects against blood ammonia increase in soccer players in an exercise intensity dependent way.

    Bassini-Cameron A, Monteiro AN, Gomes AL, Werneck-de-Castro JP, Cameron LC.

    Br J Sports Med. 2007 Nov 5; [Epub ahead of print]

    OBJECTIVE: High intensity and prolonged exercise significantly enhances the levels of plasma ammonia, a metabolite with toxic effects on the central nervous system. The main purpose of the present study was to evaluate the metabolic response of athletes to glutamine (Gln) and alanine (Ala) supplementation, since these amino acids have a significant influence on both anaplerosis and gluconeogenesis. METHODS: Professional soccer players were assigned to groups receiving either Gln or Ala supplementation (100 mg.Kg-1 body weight); this supplementation was either short- or long-term and was given immediately before exercise. The players were evaluated by two different exercise protocols, one with intervals (n=18) and the other with continuous intensity (n=12). RESULTS: Both types of exercises increased ammonia, urate, urea and creatinine in blood. Chronic Gln supplementation partially protected against hyperammonemia after a soccer match (intermittent exercise; Gln - 140 +/- 13% vs Ala - 240 +/- 37%) and after continuous exercise at 80% of the maximum heart rate (Gln - 481 +/- 44% vs placebo - 778 +/- 99%). Urate increased by 10 to 20% in all groups, independently of supplementation. Glutamine one day supplementation induced a greater elevation in urate as compared to alanine at the end of the game; however, long-term supplementation provoked a lesser increment in urate. Exercise induced similar increases in creatinine as compared to their respective controls in either acute or chronic glutamine administration. CONCLUSIONS: Taken together, our results suggest that chronically supplemented Gln protects against exercise-induced hyperammonemia depending on exercise intensity and supplementation duration.

    Energy metabolism in brain cells: effects of elevated ammonia concentrations.

    Hertz L, Kala G.

    Metab Brain Dis. 2007 Dec;22(3-4):199-218.

    Both neurons and astrocytes have high rates of glucose utilization and oxidative metabolism. Fully 20% of glucose consumption is used for astrocytic production of glutamate and glutamine, which during intense glutamatergic activity leads to an increase in glutamate content, but at steady state is compensated for by an equally intense oxidation of glutamate. The amounts of ammonia used for glutamine synthesis and liberated during glutamine hydrolysis are large, compared to the additional demand for glutamine synthesis in hyperammonemic animals and patients with hepatic encephalopathy. Nevertheless, elevated ammonia concentrations lead to an increased astrocytic glutamine production and an elevated content of glutamine combined with a decrease in glutamate content, probably mainly in a cytosolic pool needed for normal activity of the malate-asparate shuttle (MAS); another compartment generated by glutamine hydrolysis is increased. As a result of reduced MAS activity the pyruvate/lactate ratio is decreased in astrocytes but not in neurons and decarboxylation of pyruvate to form acetyl coenzyme A is reduced. Elevated ammonia concentrations also inhibit decarboxylation of alpha-ketoglutarate in the TCA cycle. This effect occurs in both neurons and astrocytes, is unrelated to MAS activity and seen after chronic treatment with ammonia even in the absence of elevated ammonia concentrations.

    Hyperammonemia-induced depletion of glutamate and branched-chain amino acids in muscle and plasma.

    Leweling H, Breitkreutz R, Behne F, Staedt U, Striebel JP, Holm E.

    J Hepatol. 1996 Nov;25(5):756-62.



    BACKGROUND/AIMS: Exogenous hyperammonemia is known to decrease the plasma levels of branched-chain amino acids (BCAA). To investigate whether changes in intracellular amino acid concentrations of muscle are associated with and may, at least in part, mediate this effect, experiments were carried out on a total of 60 male Wistar rats. METHODS: Five groups were formed in a randomized manner. Group A: no treatment; groups B1 and B2: 2-hour and 6-hour continuous central-venous infusions, respectively, of sodium salts; groups C1 and C2: 2-hour and 6-hour infusions of ammonium salts. We obtained venous blood samples and muscle biopsies. Plasma ammonia, whole blood glucose, serum insulin, blood pH, and amino acids in plasma as well as in the intracellular water of muscle were measured. RESULTS: As compared with control group A, groups C1 and C2 displayed a 3.3- and a 4-fold increase, respectively, in the plasma ammonium concentration. Regarding insulin, the ammonium-infused rats were similar to group A but not to the sodium-infused B groups, which had significantly lower insulin concentrations. Administering ammonium brought about a decline in BCAA concentrations in plasma after 2 hours and in muscle after 6 hours. The ammonium-induced fall in intracellular BCAA values was preceded by an increase of glutamine as well as by a decrease of glutamate and alanine in both plasma and muscle. CONCLUSIONS: It is pointed out that the inter-group differences in serum insulin, although possibly accounting for some of the findings, can by no means explain the entire pattern of amino acid concentrations seen after the ammonium infusions. Instead, our results agree with the hypothesis that hyperammonemia indirectly lowers the plasma levels of BCAA by stimulating glutamine synthesis, thus reducing the intracellular glutamate pool, which is likely to be restored, at least in part, by an intensified BCAA transamination. Clarification is needed as to whether carbon skeletons derived from valine and isoleucine additionally contribute to replenishing the glutamate pool.

    Exercise-induced hyperammonemia: peripheral and central effects.

    Banister EW, Cameron BJ.

    Int J Sports Med. 1990 May;11 Suppl 2:S129-42.

    The intent of this paper is to review the recent literature on exercise-induced hyperammonemia (EIH) and to compare the current interpretations of ammonia accumulation during exercise with the recognized clinical symptoms of progressive ammonia toxicity. In doing so, we will speculate on possible exercise-induced symptoms of CNS dysfunction which could result from elevated ammonia during intense short-duration or prolonged exercise. Ammonia is a ubiquitous metabolic product producing multiple effects on physiological and biochemical systems. Its concentration in several body compartments is elevated during exercise, predominantly by increased activity of the purine nucleotide cycle (PNC) in skeletal muscle. Depending on the intensity and duration of exercise, muscle ammonia may be elevated to the extent that it leaks (diffuses) from muscle to blood, and thereby can be carried to other organs. The direction of movement of ammonia or the ammonium ion is dependent on concentration and pH gradients between tissues. In this manner, ammonia can also cross the blood-brain barrier (BBB), although the rate of diffusion of ammonia from blood to brain during exercise is unknown. It seems reasonable to assume that exhaustive exercise may induce a state of acute ammonia toxicity which, although transient and reversible relative to disease states, may be severe enough in critical regions of the CNS to affect continuing coordinated activity. Regional differences in brain ammonia content, detoxification capacity, and specific sensitivity may account for the variability of precipitating factors and latency of response in CNS-mediated dysfunction arising from an exercise stimulus, e. g., motor incoordination, ataxia, stupor. There have been numerous suggestions that elevated ammonia is associated with, or perhaps is responsible for, exercise fatigue, although evidence for this relies extensively on temporal relationships. Fatigue may become manifest both as a peripheral organ or central nervous system phenomenon, or combination of both. Thus, we must examine the sequential or concomitant changes in ammonia concentration occurring in the periphery, the central nervous system (CNS), and the cerebrospinal fluid (CSF) induced by any effector, not only exercise, to interpret and rationalize the diverse physical, physiological, biochemical, and clinical symptoms produced by hyperammonemic states. Since more is known about elevated brain ammonia during other diverse conditions such as disease states, chemically induced convulsion, and hyperbaric hyperoxia, some of these relevant data are discussed.
    ]
    Last edited by deserusan; 11-17-2007 at 05:22 PM.
    "I just use my muscles as a conversation piece, like someone walking a cheetah down 42nd Street." - Arnold Schwarzenegger

    Heretic....
    Reply With Quote

  15. #15
    Actual Pharmacist Bane's Avatar
    Join Date: Oct 2002
    Location: Greece
    Posts: 5,699
    Rep Power: 18112
    Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000)
    Bane is offline
    Originally Posted by NO HYPE View Post
    Aren't the "tons" in which you speak of, supplied by normal plasma glutamine concentrations? I was under the impression that in times of normal health.... GI enterocytes/liver do not require enough glutamine to significantly deplete plasma concentrations (as opposed to the amounts of glutamine being drawn from the plasma for skeletal muscle activity/repair).
    In times of normal halth the muscles are the body's main glutamine producing factory and they provide ti to the other tissues. Glutamine getting to the GI tract is somewhat hard compared to getting it from the food availabe, that's why glutamine has such poor oral bioavailability
    Reply With Quote

  16. #16
    Registered User SinewySam's Avatar
    Join Date: Dec 2004
    Posts: 977
    Rep Power: 219
    SinewySam is on a distinguished road. (+10) SinewySam is on a distinguished road. (+10) SinewySam is on a distinguished road. (+10) SinewySam is on a distinguished road. (+10) SinewySam is on a distinguished road. (+10) SinewySam is on a distinguished road. (+10) SinewySam is on a distinguished road. (+10) SinewySam is on a distinguished road. (+10) SinewySam is on a distinguished road. (+10) SinewySam is on a distinguished road. (+10) SinewySam is on a distinguished road. (+10)
    SinewySam is offline
    So...oral supplemental glutamine may have exert is beneficial effects on us indirectly through the better handling of ammonia?
    Reply With Quote

  17. #17
    Actual Pharmacist Bane's Avatar
    Join Date: Oct 2002
    Location: Greece
    Posts: 5,699
    Rep Power: 18112
    Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000)
    Bane is offline
    Originally Posted by SinewySam View Post
    So...oral supplemental glutamine may have exert is beneficial effects on us indirectly through the better handling of ammonia?
    There are better ways to help your body handle possible excess ammonia than taking 50grams glutamine per day
    Reply With Quote

  18. #18
    I <3 Osteo-Sport TheUnlikelyToad's Avatar
    Join Date: May 2002
    Location: Harrisburg, Pennsylvania, United States
    Age: 38
    Posts: 7,063
    Rep Power: 11390
    TheUnlikelyToad is a splendid one to behold. (+10000) TheUnlikelyToad is a splendid one to behold. (+10000) TheUnlikelyToad is a splendid one to behold. (+10000) TheUnlikelyToad is a splendid one to behold. (+10000) TheUnlikelyToad is a splendid one to behold. (+10000) TheUnlikelyToad is a splendid one to behold. (+10000) TheUnlikelyToad is a splendid one to behold. (+10000) TheUnlikelyToad is a splendid one to behold. (+10000) TheUnlikelyToad is a splendid one to behold. (+10000) TheUnlikelyToad is a splendid one to behold. (+10000) TheUnlikelyToad is a splendid one to behold. (+10000)
    TheUnlikelyToad is offline
    Originally Posted by Bane View Post
    In times of normal halth the muscles are the body's main glutamine producing factory and they provide ti to the other tissues. Glutamine getting to the GI tract is somewhat hard compared to getting it from the food availabe, that's why glutamine has such poor oral bioavailability
    This is why oral glutamine will throw PRAL scores of a meal to a positive... reversing your body's own catabolic process in favor of anabolism.
    Xtreme Formulations
    Representative

    ||Bringing my a-game since '00||
    Reply With Quote

  19. #19
    3D Water Chestnuts NO HYPE's Avatar
    Join Date: Jun 2006
    Posts: 14,979
    Rep Power: 31610
    NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000)
    NO HYPE is offline

    Thumbs up

    Originally Posted by Bane View Post
    In times of normal halth the muscles are the body's main glutamine producing factory and they provide ti to the other tissues. Glutamine getting to the GI tract is somewhat hard compared to getting it from the food availabe, that's why glutamine has such poor oral bioavailability
    Thanks B.
    ~

    Wherever progression lacks.... regress can be found in abundance.
    Reply With Quote

  20. #20
    3D Water Chestnuts NO HYPE's Avatar
    Join Date: Jun 2006
    Posts: 14,979
    Rep Power: 31610
    NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000) NO HYPE has much to be proud of. One of the best! (+20000)
    NO HYPE is offline
    Originally Posted by Bane View Post
    There are better ways to help your body handle possible excess ammonia than taking 50grams glutamine per day
    ~

    Wherever progression lacks.... regress can be found in abundance.
    Reply With Quote

  21. #21
    The Gun Show Guardian's Avatar
    Join Date: Mar 2003
    Age: 34
    Posts: 13,685
    Rep Power: 5306
    Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000)
    Guardian is offline
    The way I figure it is glutamine is the most rapidly used amino acid in training individuals, taking it certaintly isnt going to do any harm. Even if most of it is used in the gut, that will spare glutamine elsewhere in the body.

    Some compounds benefits are from circular reasons as opposed to direct explanations.
    Reply With Quote

  22. #22
    Registered User ToD2's Avatar
    Join Date: Nov 2007
    Age: 48
    Posts: 4
    Rep Power: 0
    ToD2 has no reputation, good or bad yet. (0) ToD2 has no reputation, good or bad yet. (0) ToD2 has no reputation, good or bad yet. (0) ToD2 has no reputation, good or bad yet. (0) ToD2 has no reputation, good or bad yet. (0) ToD2 has no reputation, good or bad yet. (0)
    ToD2 is offline
    Originally Posted by Guardian View Post
    The way I figure it is glutamine is the most rapidly used amino acid in training individuals, taking it certaintly isnt going to do any harm. Even if most of it is used in the gut, that will spare glutamine elsewhere in the body.

    Some compounds benefits are from circular reasons as opposed to direct explanations.
    I think thats what the original supplementation logic suggested and what warranted these further studies. This is why I started to take glutamine, but the science is saying the contrary. Some supplementation benefits may be indirect or circular but the underlying result is no result.
    Reply With Quote

  23. #23
    ¯\_(ツ)_/¯ INGENIUM's Avatar
    Join Date: Jan 2007
    Posts: 8,672
    Rep Power: 164002
    INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000)
    INGENIUM is offline
    Originally Posted by TheUnlikelyToad View Post
    This is why oral glutamine will throw PRAL scores of a meal to a positive... reversing your body's own catabolic process in favor of anabolism.
    you can also do this by adding some fat to your meal...or eating vegetables with a meal...

    I don't understand why everyone is grasping at straws trying to find a viable use for supplemental l-glutamine...

    sure, there are some things it can do...but does any of those really justify its use?
    Reply With Quote

  24. #24
    The Gun Show Guardian's Avatar
    Join Date: Mar 2003
    Age: 34
    Posts: 13,685
    Rep Power: 5306
    Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000) Guardian is a name known to all. (+5000)
    Guardian is offline
    Glutamine can be synthesized by the body from other essential amino acids (which is why glutamine isnt an eaa). Wouldn't it make logical sense supplementing with glutamine would spare other amino acids that otherwise may be used to create glutamine in the body? This benefit wouldnt really show in most of these studies but could indeed be valuable.
    Reply With Quote

  25. #25
    ¯\_(ツ)_/¯ INGENIUM's Avatar
    Join Date: Jan 2007
    Posts: 8,672
    Rep Power: 164002
    INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000) INGENIUM has a reputation beyond repute. Second best rank possible! (+100000)
    INGENIUM is offline
    Originally Posted by Guardian View Post
    Glutamine can be synthesized by the body from other essential amino acids (which is why glutamine isnt an eaa). Wouldn't it make logical sense supplementing with glutamine would spare other amino acids that otherwise may be used to create glutamine in the body? This benefit wouldnt really show in most of these studies but could indeed be valuable.
    it sounds good on paper, however, science has shown that glutamine supplementation leads to ZERO favorable changes in body composition, ZERO increase in protein synthesis, ZERO effect on athletic performance....

    so, this purported "benefit" appears to be of no significance
    Reply With Quote

  26. #26
    Up And Out cakedonkey's Avatar
    Join Date: Sep 2004
    Location: Massachusetts, United States
    Posts: 6,849
    Rep Power: 3502
    cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500) cakedonkey is a glorious beacon of knowledge. (+2500)
    cakedonkey is offline
    Originally Posted by INGENIUM View Post
    it sounds good on paper, however, science has shown that glutamine supplementation leads to ZERO favorable changes in body composition, ZERO increase in protein synthesis, ZERO effect on athletic performance....

    so, this purported "benefit" appears to be of no significance

    Well said. Bumping this.
    SAN Nutrition
    sann.net / pumpedmag.com / starmarklabs.com
    Reply With Quote

  27. #27
    Scrum-Half Pro-Choice's Avatar
    Join Date: Jan 2005
    Location: ATL
    Age: 32
    Posts: 326
    Rep Power: 193
    Pro-Choice has no reputation, good or bad yet. (0) Pro-Choice has no reputation, good or bad yet. (0) Pro-Choice has no reputation, good or bad yet. (0) Pro-Choice has no reputation, good or bad yet. (0) Pro-Choice has no reputation, good or bad yet. (0) Pro-Choice has no reputation, good or bad yet. (0) Pro-Choice has no reputation, good or bad yet. (0) Pro-Choice has no reputation, good or bad yet. (0) Pro-Choice has no reputation, good or bad yet. (0) Pro-Choice has no reputation, good or bad yet. (0) Pro-Choice has no reputation, good or bad yet. (0)
    Pro-Choice is offline
    Originally Posted by Guardian View Post
    Glutamine can be synthesized by the body from other essential amino acids (which is why glutamine isnt an eaa). Wouldn't it make logical sense supplementing with glutamine would spare other amino acids that otherwise may be used to create glutamine in the body? This benefit wouldnt really show in most of these studies but could indeed be valuable.
    The fact that glutamine isn't an eaa speaks to me as more of a reason not to heavily supplement with it. Since glutamine can be biosynthesized, wouldn't that be a good reason to intake more of the essential acids and skip the middle man? By your logic, supplementing with any other nonessential acid such as tyrosine would also be a good idea.

    Also glutamine is primarily synthesized from glutamic acid. If not ingesting enough protein and your body is required to synthesize glutamine, you would really only be sparing your body its stores of this one other amino acid, not all of the other 18 because they aren't used as precursors.
    Reply With Quote

  28. #28
    Actual Pharmacist Bane's Avatar
    Join Date: Oct 2002
    Location: Greece
    Posts: 5,699
    Rep Power: 18112
    Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000)
    Bane is offline
    Originally Posted by deserusan View Post
    Glutamine protects against blood ammonia increase in soccer players in an exercise intensity dependent way.

    Bassini-Cameron A, Monteiro AN, Gomes AL, Werneck-de-Castro JP, Cameron LC.

    Br J Sports Med. 2007 Nov 5; [Epub ahead of print]




    Energy metabolism in brain cells: effects of elevated ammonia concentrations.

    Hertz L, Kala G.

    Metab Brain Dis. 2007 Dec;22(3-4):199-218.




    Hyperammonemia-induced depletion of glutamate and branched-chain amino acids in muscle and plasma.

    Leweling H, Breitkreutz R, Behne F, Staedt U, Striebel JP, Holm E.

    J Hepatol. 1996 Nov;25(5):756-62.






    Exercise-induced hyperammonemia: peripheral and central effects.

    Banister EW, Cameron BJ.

    Int J Sports Med. 1990 May;11 Suppl 2:S129-42.

    ]
    1. It has been established that chronic hyperammonaemia, whether caused by portacaval shunting or other means, leads to a variety of metabolic changes, including a depression in the cerebral metabolic rate of glucose (CMRGlc) increased permeability of the blood-brain barrier to neutral amino acids, and an increase in the brain content of aromatic amino acids. The preceding paper [Jessy, DeJoseph & Hawkins (1991) Biochem. J. 277, 693-696] showed that the depression in CMRGlc caused by hyperammonaemia correlated more closely with glutamine, a metabolite of ammonia, than with ammonia itself. This suggested that ammonia (NH3 and NH4+) was without effect. The present experiments address the question whether ammonia, in the absence of net glutamine synthesis, induces any of the metabolic symptoms of cerebral dysfunction associated with hyperammonaemia. 2. Small doses of methionine sulphoximine, an inhibitor of glutamine synthetase, were used to raise the plasma ammonia levels of normal rats without increasing the brain glutamine content. These hyperammonaemic rats, with plasma and brain ammonia levels equivalent to those known to depress brain function, behaved normally over 48 h. There was no depression of cerebral energy metabolism (i.e. the rate of glucose consumption). Contents of key intermediary metabolites and high-energy phosphates were normal. Neutral amino acid transport (tryptophan and leucine) and the brain contents of aromatic amino acids were unchanged. 3. The data suggest that ammonia is without effect at concentrations less than 1 mumol/ml if it is not converted into glutamine. The deleterious effect of chronic hyperammonaemia seems to begin with the synthesis of glutamine.
    full text at: http://www.pubmedcentral.nih.gov/art...bmedid=1872806

    The role of hyperammonemia in the pathogenesis of cerebral edema was investigated using mongrel dogs to develop a treatment for cerebral edema in acute hepatic failure. Intravenous infusion of ammonium acetate alone into dogs did not induce brain edema, although blood ammonia reached unphysiologically high levels. However, ammonium acetate infusion during mannitol-induced reversible (osmotic) opening of the blood-brain barrier (BBB) effectively induced cytotoxic brain edema. Pretreatment with a branched-chain amino acid (BCAA; valine, leucine and isoleucine) solution prevented an increase in intracranial pressure (ICP) and brain water content, and caused a decrease in brain ammonia content and an increase in brain BCAA and glutamic acid. The results suggest that ammonia plays an important role in the pathogenesis of cerebral edema during acute hepatic failure and that BCAAs accelerate ammonia detoxification in the brain.
    L-Leucine prevents ammonia-induced changes in glutamate receptors in the brain and in visual evoked potentials in the rabbit.
    Ferenci P, Pappas CS, Jones EA.

    The effect of L-leucine on glutamate receptors in the brain and on visual evoked potentials was studied in hyperammonemic rabbits. Hyperammonemia was induced by the iv infusion of 2.1 mmol NH4Cl/h over 3 hr. Hyperammonemia was followed by a 116% increase in the specific binding of 3H-glutamate to synaptic membranes prepared from the hippocampus. This increase was due to both an increase in the affinity and in the density of the glutamate receptor. The simultaneous infusion of L-leucine (6.7 mmol/hr) completely prevented the ammonia-induced increase in the specific glutamate binding, whereas L-valine and D-leucine had no effect. Hyperammonemia was also associated with typical, reproducible, and reversible changes in visual evoked potentials. The amplitudes of the first negative and the second positive peak decreased, whereas the latencies of these peaks remained unchanged. The simultaneous infusion of L-leucine completely prevented these changes. These findings indicate (1) that L-leucine prevents ammonia-induced changes in the glutamatergic excitatory neurotransmitter system and (2) that pharmacologic doses of L-leucine modulate the effects of hyperammonemia on central neurotransmission as assessed by visual evoked potentials. A causal relationship between the effects of L-leucine on ammonia-induced changes in glutamate receptors and in visual evoked potentials cannot be inferred with confidence. These findings provide a potential alternative explanation for the apparent beneficial effects of infusions of branched-chain amino acids on hepatic encephalography in patients with chronic liver disease.
    Primary astrocyte cultures were subjected to different experimental schedules using several concentrations of ammonia (1, 3, and 5 mM ammonium chloride), serum (2.5%, 5%, and 12%), and glutamine (0.5, 1, and 3 mM) to analyze the involvement of calcineurin (CaN) in hyperammonemia and its relation with p38MAPK-diP and ciliary neurotrophic factor (CNTF). We demonstrated that exposure to ammonia affects CaN content, and confirmed the ammonia-induced reduction of CNTF expression; however, the involvement of CaN and p38MAPK-diP in CNTF reduction could not be confirmed. On the contrary, an inverse relationship between CaN and p38MAPK-diP contents was clearly demonstrated. GADD153/CHOP10 content was always higher under hyperammonemic conditions as well as under glutamine exposure, probably due to the osmotic stress provoked by glutamine accumulation, which was induced after exposure to ammonia. Statistical analysis demonstrated significant interactions of ammonia and serum for CaN, GADD153/CHOP10 and CNTF contents. The exposure to glutamine also induced changes in GADD153/CHOP10 and CaN; however, CNTF content was not affected. In conclusion, CaN content was affected by exposure to ammonia and glutamine; the serum content of the culture medium had a strong influence on the astroglial response to ammonium chloride, and glutamine exposure only reproduced some of the ammonia effects.
    Cerebral hyperammonemia is a hallmark of hepatic encephalopathy, a debilitating condition arising secondary to liver disease. Pyruvate oxidation including tricarboxylic acid (TCA) cycle metabolism has been suggested to be inhibited by hyperammonemia at the pyruvate and alpha-ketoglutarate dehydrogenase steps. Catabolism of the branched-chain amino acid isoleucine provides both acetyl-CoA and succinyl-CoA, thus by-passing both the pyruvate dehydrogenase and the alpha-ketoglutarate dehydrogenase steps. Potentially, this will enable the TCA cycle to work in the face of ammonium-induced inhibition. In addition, this will provide the alpha-ketoglutarate carbon skeleton for glutamate and glutamine synthesis by glutamate dehydrogenase and glutamine synthetase (astrocytes only), respectively, both reactions fixing ammonium. Cultured cerebellar neurons (primarily glutamatergic) or astrocytes were incubated in the presence of either [U-13C]glucose (2.5 mM) and isoleucine (1 mM) or [U-13C]isoleucine and glucose. Cell cultures were treated with an acute ammonium chloride load of 2 (astrocytes) or 5 mM (neurons and astrocytes) and incorporation of 13C-label into glutamate, aspartate, glutamine and alanine was determined employing mass spectrometry. Labeling from [U-13C]glucose in glutamate and aspartate increased as a result of ammonium-treatment in both neurons and astrocytes, suggesting that the TCA cycle was not inhibited. Labeling in alanine increased in neurons but not in astrocytes, indicating elevated glycolysis in neurons. For both neurons and astrocytes, labeling from [U-13C]isoleucine entered glutamate and aspartate albeit to a lower extent than from [U-13C]glucose. Labeling in glutamate and aspartate from [U-13C]isoleucine was decreased by ammonium treatment in neurons but not in astrocytes, the former probably reflecting increased metabolism of unlabeled glucose. In astrocytes, ammonia treatment resulted in glutamine production and release to the medium, partially supported by catabolism of [U-13C]isoleucine. In conclusion, i) neuronal and astrocytic TCA cycle metabolism was not inhibited by ammonium and ii) isoleucine may provide the carbon skeleton for synthesis of glutamate/glutamine in the detoxification of ammonium.
    Reply With Quote

  29. #29
    Actual Pharmacist Bane's Avatar
    Join Date: Oct 2002
    Location: Greece
    Posts: 5,699
    Rep Power: 18112
    Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000) Bane is a splendid one to behold. (+10000)
    Bane is offline
    cont
    Glutamine (Gln) abounds in the central nervous system (CNS), and its interstitial and cerebrospinal fluid (CSF) concentrations are at least one order of magnitude higher than of any other amino acid. Gln transport from blood to the brain is insufficient to meet the demand of the brain tissues for this amino acid. This demand is met by intracerebral Gln synthesis from glutamate (Glu), a reaction carried out by glutamine synthetase (GS), an enzyme residing in astrocytes. A major proportion of astroglia-derived Gln is shuttled to neurons where it is degraded by phosphate-activated glutaminase (PAG) giving rise to the excitatory neurotransmitter amino acid Glu, which is also a precursor of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Glu released from neurons is taken up by astrocytes, and reconverted to Gln, closing the so called "glutamate-glutamine" cycle. A portion of Gln serves as an energy metabolite, and part of it leaves the brain to blood. Gln efflux from astrocytes, its neuronal uptake and egress to the blood via the cerebral capillary endothelial cells is mediated by different amino acid carriers showing i) considerable preference for Gln, ii) distribution between astrocytes and neurons that favors astrocyte-to-neuron fluxes of the amino acid. The Gln-specific carriers also largely contribute to Gln efflux from the brain to the vascular bed. Excessive accumulation of Gln in brain cells may be deleterious to brain function. In hyperammonemia associated with acute liver failure, excess Gln leads to cerebral edema, which largely results from its interference with mitochondrial function and partly from its osmotic action. Future analyses of the roles of Gln in both normal and abnormal cerebral metabolism and function will have to account for its newly recognized direct involvement in the regulation of gene transcription and/or translation.

    Glutamine, a byproduct of ammonia detoxification, is found elevated in brain in hepatic encephalopathy (HE) and other hyperammonemic disorders. Such elevation has been implicated in some of the deleterious effects of ammonia on the central nervous system (CNS). Recent studies have shown that glutamine results in the induction of the mitochondrial permeability transition (MPT) in cultured astrocytes. We examined whether glutamine shows similar effects in cultured neurons. Both cultured astrocytes and neurons were exposed to glutamine (6.5 mM) for 24 hr and the MPT was assessed by changes in cyclosporin A (CsA)-sensitive inner mitochondrial membrane potential (DeltaPsi(m)) using the potentiometric dye tetramethylrhodamine ethyl ester (TMRE). Glutamine significantly dissipated the DeltaPsi(m) in astrocytes as demonstrated by a decrease in mitochondrial TMRE fluorescence, a process that was blocked by CsA. On the other hand, treatment of cultured neurons with glutamine had no effect on the DeltaPsi(m). Dissipation of the DeltaPsi(m) in astrocytes by glutamine was blocked by treatment with 6-diazo-5-oxo-L-norleucine (DON; 100 microM), suggesting that glutamine hydrolysis and the subsequent generation of ammonia, which has been shown previously to induce the MPT, might be involved in MPT induction by glutamine. These data indicate that astrocytes but not neurons are vulnerable to the toxic effects of glutamine. The selective induction of oxidative stress and the MPT by glutamine in astrocytes may partially explain the deleterious affects of glutamine on the CNS in the setting of hyperammonemia, as well as account for the predominant involvement of astrocytes in the pathogenesis of HE and other hyperammonemic conditions. (c) 2004 Wiley-Liss, Inc.
    Ammonia is a neurotoxin that predominantly affects astrocytes. Disturbed mitochondrial function and oxidative stress, factors implicated in the induction of the mitochondrial permeability transition (MPT), appear to be involved in the mechanism of ammonia neurotoxicity. We have recently shown that ammonia induces the MPT in cultured astrocytes. To elucidate the mechanisms of the MPT, we examined the role of oxidative stress and glutamine, a byproduct of ammonia metabolism. The ammonia-induced MPT was blocked by antioxidants, suggesting a causal role of oxidative stress. Direct application of glutamine (4.5-7.0 mM) to cultured astrocytes increased free radical production and induced the MPT. Treatment of astrocytes with the mitochondrial glutaminase inhibitor, 6-diazo-5-oxo-L-norleucine, completely blocked free radical formation and the MPT, suggesting that high ammonia concentrations in mitochondria resulting from glutamine hydrolysis may be responsible for the effects of glutamine. These studies suggest that oxidative stress and glutamine play major roles in the induction of the MPT associated with ammonia neurotoxicity.
    Ammonia reduction is the target for therapy of hepatic encephalopathy, but lack of quantitative data about how the individual organs handle ammonia limits our ability to develop novel therapeutic strategies. The study aims were to evaluate interorgan ammonia metabolism quantitatively in a devascularized pig model of acute liver failure (ALF). Ammonia and amino acid fluxes were measured across the portal drained viscera (PDV), kidneys, hind leg, and lungs in ALF pigs. ALF pigs developed hyperammonemia and increased glutamine levels, whereas glutamate levels were decreased. PDV contributed to the hyperammonemic state mainly through increased shunting and not as a result of increased glutamine breakdown. The kidneys were quantitatively as important as PDV in systemic ammonia release, whereas muscle took up ammonia. Data suggest that the lungs are able to remove ammonia from the circulation during the initial stage of ALF. Our study provides new data supporting the concept of glutamate deficiency in a pig model of ALF. Furthermore, the kidneys are quantitatively as important as PDV in ammonia production, and the muscles play an important role in ammonia removal.
    Because increases in plasma glutamine concentrations are almost always associated with hyperammonemia in patients with urea cycle disorders, we determined the correlation between these two variables for 2 years in a child with ornithine transcarbamylase deficiency. A correlation coefficient of 0.77 (p less than 0.0001) was found. Hyperammonemia was rarely observed when plasma glutamine levels were near normal. These data suggest that one goal of therapy is the maintenance of plasma glutamine levels at or near normal values.
    Mechanisms involved in hepatic encephalopathy still remain to be defined. Nonetheless, it is well recognized that ammonia is a major factor in its pathogenesis, and that the astrocyte represents a major target of its CNS toxicity. In vivo and in vitro studies have shown that ammonia evokes oxidative/nitrosative stress, mitochondrial abnormalities (the mitochondrial permeability transition, MPT) and astrocyte swelling, a major component of the brain edema associated with fulminant hepatic failure. How ammonia brings about these changes in astrocytes is not well understood. It has long been accepted that the conversion of glutamate to glutamine, catalyzed by glutamine synthetase, a cytoplasmic enzyme largely localized to astrocytes in brain, represented the principal means of cerebral ammonia detoxification. Yet, the "benign" aspect of glutamine synthesis has been questioned. This article highlights evidence that, at elevated levels, glutamine is indeed a noxious agent. We also propose a mechanism by which glutamine executes its toxic effects in astrocytes, the "Trojan horse" hypothesis. Much of the newly synthesized glutamine is subsequently metabolized in mitochondria by phosphate-activated glutaminase, yielding glutamate and ammonia. In this manner, glutamine (the Trojan horse) is transported in excess from the cytoplasm to mitochondria serving as a carrier of ammonia. We propose that it is the glutamine-derived ammonia within mitochondria that interferes with mitochondrial function giving rise to excessive production of free radicals and induction of the MPT, two phenomena known to bring about astrocyte dysfunction, including cell swelling. Future therapeutic approaches might include controlling excessive transport of newly synthesized glutamine to mitochondria and its subsequent hydrolysis.
    Reply With Quote

  30. #30
    Nimbus Nutrition Rep leonidas300's Avatar
    Join Date: Dec 2006
    Posts: 6,775
    Rep Power: 15589
    leonidas300 is a splendid one to behold. (+10000) leonidas300 is a splendid one to behold. (+10000) leonidas300 is a splendid one to behold. (+10000) leonidas300 is a splendid one to behold. (+10000) leonidas300 is a splendid one to behold. (+10000) leonidas300 is a splendid one to behold. (+10000) leonidas300 is a splendid one to behold. (+10000) leonidas300 is a splendid one to behold. (+10000) leonidas300 is a splendid one to behold. (+10000) leonidas300 is a splendid one to behold. (+10000) leonidas300 is a splendid one to behold. (+10000)
    leonidas300 is offline
    Originally Posted by INGENIUM View Post
    it sounds good on paper, however, science has shown that glutamine supplementation leads to ZERO favorable changes in body composition, ZERO increase in protein synthesis, ZERO effect on athletic performance....

    so, this purported "benefit" appears to be of no significance
    I have no idea why people keep trying to justify using Glutamine despite the fact that every single study shows it to be worthless. It is like trying to argue that the world is still despite all the evidence to the contrary.
    Certitude is the enemy of wisdom.
    "We have just enough religion to make us hate, but not enough to make us love one another." Johnathan Swift.

    Remember this principle: if you have to chew something, it ain't anabolic. Alan Aragon

    NIMBUS NUTRITION "When Performance is Everything!"
    POSEIDON
    clay@nimbusnutrition.com
    Reply With Quote

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts