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."
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?
06-29-2011, 10:20 PM #1
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Arginine - Growth Hormone Stimulator?Confront the beast that haunts you. Only then will you be free.
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07-04-2011, 11:14 AM #2
07-06-2011, 08:09 AM #3
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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.
Originally Posted by J Gerontol A Biol Sci Med Sci. 1999 Aug;54(8):M395-9.
Increase in sleep related GH and Prl secretion after chronic arginine aspartate administration in man.
Originally Posted by Acta Endocrinol (Copenh). 1982 Jan;99(1):18-23.أشهد أن لا إله إلاَّ الله و أشهد أن محمد رسول الله
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07-06-2011, 10:01 AM #4
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.
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.
Originally Posted by in10city[/QUOTEOriginally Posted by NO HYPEOriginally Posted by in10city
07-31-2011, 08:55 AM #5
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