Protein Peptides and Growth Hormones February 22, 2009 StaffWriter
GHRP – 2 is a true hGH secretagogue. Which means it stimulates the body’s own secretion of hGH as explained in the study below. Human Growth hormone has been shown in studies to promote lean body mass and reduce adiposity (fat). ‘The group compared ITT to stimulation with GH releasing peptide 2 (GHRP-2). The synthetic hexapeptide, also named pralmorelin, is derived from a metenkephalin peptide. It is the most potent of the family of synthetic GH stimuli known in humans and acts via the endogenous ghrelin receptor (12). As these receptors have been identified both in the hypothalamus and the pituitary, GHRP-2 action may not be restricted to the pituitary.
Previous data confirmed by the recent work of Chihara et al. in the present issue suggest a dose-dependent and specific GH release in healthy volunteers independent of age, sex and obesity (13), and support the results of the combination tests of GHRP-2 with GHRH (14).’ GHRP – 2 also has a protective effect on the liver and an anti-inflammatory effect. These are paramount attributes for experiments involving muscle synthesis and recovery. ‘It has been reported that growth hormone (GH)-releasing peptide-2 (GHRP-2), a ghrelin receptor agonist, has an anti-inflammatory effect. We investigated whether this GH secretagogue attenuates liver injury in LPS-treated rats. Wistar rats were simultaneously injected (ip) with LPS (1 mg/kg) and/or GHRP-2 (100 microg/kg). Serum levels of aspartate and alanine transaminases were measured as an index of liver damage. Circulating nitrites/nitrates and hepatic IGF-I and TNF-alpha were evaluated as possible mediators of GHRP-2 actions. LPS increased serum levels of transaminases and nitrites/nitrates. Moreover, LPS increased hepatic TNF-alpha and decreased hepatic IGF-I mRNAs. GHRP-2 administration attenuated the effects of LPS on transaminases, nitrites/nitrates, TNF-alpha, and IGF-I in vivo. This GHRP-2 effect does not seem to be due to modifications in food intake, since fasting did not modify serum levels of transaminases, serum nitrites/nitrates, and hepatic TNF-alpha mRNA both in vehicle rats and in LPS-injected rats. To elucidate whether GHRP-2 is acting directly on the liver, cocultures of hepatocytes and nonparenchymal cells and monocultures of isolated hepatocytes were incubated with LPS and GHRP-2. The ghrelin receptor agonist prevented an endotoxin-induced increase in transaminases and nitrite/nitrate release as well as in TNF-alpha mRNA and increased IGF-I mRNA from cocultures of hepatocytes and nonparenchymal cells, but not from monocultures. In summary, these data indicate that GHRP-2 has a protective effect on the liver in LPS-injected rats that seems to be mediated by IGF-I, TNF-alpha, and nitric oxide. Our data also suggest that the anti-inflammatory effect of GHRP-2 in the liver is exerted on nonparenchymal cells.’ GHRP 2 has demonstrated that it is very effective at stimulating GH production in test subjects. It has a short half life with peak concentrations occurring around 15 minutes and not longer than 60 minutes after administration. Effective dosages in humans range from 100mcg to 3mcg/Kg of body weight and shows to be equally effective in both men and women. Bibliography: Anderson SM, Shah N, Evans WS, Patrie JT, Bowers CY, Veldhuis JD. 2001. Short-term estradiol supplementation augments growth hormone (GH) secretory responsiveness to dose-varying GH-releasing peptide infusions in healthy postmenopausal women. J Clin Endocrinol Metab. 2001 Feb;86(2):551-60. Brabant, Georg. 2007. GH releasing peptide 2 test: the holy grail of testing GH deficiency? European Journal of Endocrinology, Vol 157, Issue 1, 29-30 Chihara K, Shimatsu A, Hizuka N, Tanaka T, Seino Y, Katofor Y; KP-102 Study Group. 2007. A simple diagnostic test using GH-releasing peptide-2 in adult GH deficiency. Eur J Endocrinol. Jul;157(1):19-27. Granado, M., Martín, AI., López-Menduiña, M., López-Calderón, A., Villanúa, MA. 2008. GH-releasing peptide-2 administration prevents liver inflammatory response in endotoxemia., Am J Physiol Endocrinol Metab., Jan;294(1):E131-41. Epub 2007 Nov Paulo RC, Cosma M, Soares-Welch C, Bailey JN, Mielke KL, Miles JM, Bowers CY, Veldhuis JD. 2008. Gonadal status and body mass index jointly determine growth hormone (GH)-releasing hormone/GH-releasing peptide synergy in healthy men. J Clin Endocrinol Metab. 2008 Mar;93(3):944-50. Epub 2007 Dec 11