Arginine - Growth Hormone Stimulator?

[Caponetta]

Arginine stimulates growth hormone secretion by suppressing Endogenous Somatostatin secretion In the anterior pituitary gland. Endogenous Somatostatin (GHIH) inhibits the release of growth hormone as well as the release of thyroid-stimulating hormone (thyrotropin).


From Endocrine Journel
"To determine how arginine (Arg) stimulates GH secretion, we investigated its interaction with GHRH in vivo and in vitro. Six normal men were studied on four occasions: 1) Arg-TRH, 30 g arginine were administered in 500 mL saline in 30 min, followed by an injection of 200 μg TRH; 2) GHRH-Arg-TRH, 100 μg GHRH-(l–44) were given iv as a bolus immediately before the Arg infusion, followed by 200 μg TRH, iv; 3) GHRH test, 100 μg GHRH were given as an iv bolus; and 4) TRH test, 200 μg TRH were given iv as a bolus dose. Blood samples were collected at 15-min intervals for 30 min before and 120 min after the start of each infusion. Anterior pituitary cells from rats were coincubated with Arg (3, 6, 15, 30, and 60 mg/mL) and GHRH (0.05, 1, 5, and 10 nmol/L) for a period of 3 h. Rat GH was measured in the medium. After Arg-TRH the mean serum GH concentration increased significantly from 0.6 to 23.3 ± 7.3 (± SE) μg/L at 60 min. TRH increased serum TSH and PRL significantly (maximum TSH, 11.1 ± 1.8 mU/L; maximum PRL, 74.6 ± 8.4 μg/L). After GHRH-Arg-TRH, the maximal serum GH level was significantly higher (72.7 ± 13.4 μg/L) than that after Arg-TRH alone, whereas serum TSH and PRL increased to comparable levels (TSH, 10.2 ± 3.0 mU/L; PRL, 64.4 ± 13.6 μg/L). GHRH alone increased serum GH to 44.9 ± 9.8 μ/L, significantly less than when GHRH, Arg, and TRH were given. TRH alone increased serum TSH to 6.6 ± 0.6 mU/L, significantly less than the TSH response to Arg-TRH. The PRL increase after TRH only also was lower (47.2 ± 6.8 μg/L) than the PRL response after Arg-TRH. In vitro Arg had no effect on basal and GHRH-stimulated GH secretion.

Our results indicate that Arg administered with GHRH led to higher serum GH levels than did a maximally stimulatory dose of GHRH or Arg alone. The serum TSH response to Arg-TRH also was greater than that to TRH alone. We conclude that the stimulatory effects of Arg are mediated by suppression of endogenous somatostatin secretion."

http://jcem.endojournals.org/content/67/6/1186.short

Additional information on study (http://www.nlm.nih.gov/medlineplus/e...cle/003377.htm)


TL;DR Somatostatin (GHIH) secretion is surpressed by high supplementation of L-Arginine. Lower levels of GHIH = more Growth Hormone produced by the pituitary gland.




Im personally skeptical, any opinions?

[trollum]

Yes IME. Other supplements that will increase GH

- alpha-gpc
- l-dopa
-l-glutamine

[MakeABanana]

Issues I have with that study in relation to human supplementation:
- The study uses rats. The differences in metabolisms can account for different effects
- 30 g of arginine is a super-high dose, even for humans. And here it is used for rats
- Arginine was delivered intravenously while most humans consume arginine orally


Oral arginine does not stimulate basal or augment exercise-induced GH secretion in either young or old adults.

Abstract
BACKGROUND:

Growth hormone (GH) helps maintain body composition and metabolism in adults. However, basal and peak GH decline with age. Exercise produces a physiologic GH response that is subnormal in elderly people. Arginine (Arg) infusion can augment GH secretion, but the efficacy of oral Arg to improve GH response to exercise has not been explored. We investigated whether oral Arg increases GH secretion in young and old people at rest and during exercise.
METHODS:

Twenty young (Y: 22.1 +/- 0.9 y; SEM) and 8 old (O: 68.5 +/- 2.1 y) male and female subjects underwent three different trials following determination of their one-repetition maximum strength (1-RM); exercise only (EO; 3 sets, 8-10 reps at 85% of 1-RM; on 12 separate resistive lifts), Arg only (5.0 g), or Arg + exercise. Blood samples were collected between successive lifts, and GH (ng x ml(-1)) was determined via RIA.
RESULTS:

In Y vs O: Basal GH secreted (area under the curve) was 543.6 +/- 84.0 vs 211.5 +/- 63.0. During EO, values were 986.6 +/- 156.6 and 517.8 +/- 85.5. Both were significantly lower in the older individuals (p < .05). Oral Arg alone did not result in any increase in GH secretion at rest (310.8 +/- 73.2 vs 262.9 +/- 141.2). When Arg was coadministered during exercise, GH release was not affected in either the young or old and appeared to be blunted in the young compared to the exercise only trial in the young.
CONCLUSION:

Based upon these findings, we concluded that oral Arg does not stimulate GH secretion and may impair GH release during resistive exercise.

However, large oral doses of arginine given at night before sleep show interesting results in GH levels.

Increase in sleep related GH and Prl secretion after chronic arginine aspartate administration in man.

Abstract
BACKGROUND:

Growth hormone (GH) helps maintain body composition and metabolism in adults. However, basal and peak GH decline with age. Exercise produces a physiologic GH response that is subnormal in elderly people. Arginine (Arg) infusion can augment GH secretion, but the efficacy of oral Arg to improve GH response to exercise has not been explored. We investigated whether oral Arg increases GH secretion in young and old people at rest and during exercise.
METHODS:

Twenty young (Y: 22.1 +/- 0.9 y; SEM) and 8 old (O: 68.5 +/- 2.1 y) male and female subjects underwent three different trials following determination of their one-repetition maximum strength (1-RM); exercise only (EO; 3 sets, 8-10 reps at 85% of 1-RM; on 12 separate resistive lifts), Arg only (5.0 g), or Arg + exercise. Blood samples were collected between successive lifts, and GH (ng x ml(-1)) was determined via RIA.
RESULTS:

In Y vs O: Basal GH secreted (area under the curve) was 543.6 +/- 84.0 vs 211.5 +/- 63.0. During EO, values were 986.6 +/- 156.6 and 517.8 +/- 85.5. Both were significantly lower in the older individuals (p < .05). Oral Arg alone did not result in any increase in GH secretion at rest (310.8 +/- 73.2 vs 262.9 +/- 141.2). When Arg was coadministered during exercise, GH release was not affected in either the young or old and appeared to be blunted in the young compared to the exercise only trial in the young.
CONCLUSION:

Based upon these findings, we concluded that oral Arg does not stimulate GH secretion and may impair GH release during resistive exercise.

[NO HYPE]

Temporarily elevating serum GH and/or IGF-1 levels via amino acids and/or OTC supplements, elicits minimal to no benefits whatsoever in terms of overall gains.

EXAMPLE:
J Strength Cond Res. 2010 Apr;24(4):1082-90.
Zajac A, Poprzecki S, Zebrowska A, Chalimoniuk M, Langfort J.
Arginine and Ornithine Supplementation Increases Growth Hormone and Insulin-Like Growth Factor-1 Serum Levels After Heavy-Resistance Exercise in Strength-Trained Athletes.

They took 2,200 mg of L-ornithine, 3,000 mg of L-Arg and 12 mg of vitamin B12 twice daily for 3 weeks. The testing protocol was 5 sets of 5 repetitions of the back squat with 5 minutes of rest between sets which would not elicit a strong GH response normally and didn't do much here for GH even with the supplements - statistically significant but not clinically significant [GH post test 2.5 ng/ml vs. 3.5 ng/ml from 0.5 ng/ml] [IGF-1 post test was 425 ng/ml vs. 600 ng/ml from 300 ng/ml and 400 ng/ml respectively]. Something more 'bodybuilding' centric that increased GH normally would have been interesting to compare to other related studies. Anyway the effect of these little serum squirts on muscle growth, even of hepatic IGF-1, are debatable as a few recent studies by Dr. Phillips have contended. This study didn't differentiate between any IGF-1 splice variants / intramuscular growth factors and expression. What's going on intramuscularly seems to be of more importance. Probably the most notable thing was that they didn't even take the supplements before the test.

Did they even keep record of muscle growth and/or overall gains for endpoint comparisons? Either way, I'm betting there were no significant variations.

They measured body mass and body composition but there wasn't any change in either to note.

[JoeCannonMSCSCS]

Im skeptical also. They gave people injections of Arg. thats very different than arg supplements.