I think this hormone will soon become a bodybuilding staple as it works by stimulating GH release from the pituitary and hypothalamus. This imparts a highly anabolic effect not unlike that experienced through natural GH secretion.
This Article is from the Journal of Endocrinology, Vol 171, Issue 3, 481-489
Copyright © 2001 by Society for Endocrinology
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Articles
Pharmacological profile of a new orally active growth hormone secretagogue, SM-130686
J Nagamine, R Nagata, H Seki, N Nomura-Akimaru, Y Ueki, K Kumagai, M Taiji, and H Noguchi
SM-130686, an oxindole derivative, is a novel orally active GH secretagogue (GHS) which is structurally distinct from previously reported GHSs such as MK-677, NN703 and hexarelin. SM-130686 stimulates GH release from cultured rat pituitary cells in a dose-dependent manner. Half-maximum stimulation was observed at a concentration of 6.3+/-3.4 nM. SM-130686-induced GH release was inhibited by a GHS antagonist, but not by a GH-releasing hormone antagonist. SM-130686 dose-dependently inhibited the binding of radiolabeled ligand, (35)S-MK-677, to human GHS receptor 1a (IC(50)=1.2 nM). This indicates that SM-130686 stimulates GH release through the GHS receptor. The effect of a single oral administration of SM-130686 on GH release in pentobarbital-anesthetized rats was studied. After treatment with 10 mg/kg SM-130686, plasma GH concentrations measured by radioimmunoassay significantly increased, reaching a peak at 20-45 min, and remained above baseline during the experimental period (60 min). The anabolic effect of repetitive SM-130686 administration was studied in rats. Rats received 10 mg/kg SM-130686 orally twice a day and were weighed every day for 9 days. At day 9 there was a significant increase in both the body weight and the fat free mass (19.5+/-2.1 and 18.1+/-7.5 g respectively). Serum IGF-I concentration was also significantly elevated 6 h after the last dose of SM-130686. An endogenous GHS ligand for the GHS receptor has recently been identified from stomach extract and designated as ghrelin. The GH-releasing activity in vitro relative to ghrelin (100%) was about 52% for SM-130686. It is likely that SM-130686 is a partial agonist for the GHS receptor. In summary, we describe here an orally active GHS, SM-130686, which acts through the GHS receptor. Repetitive administration of SM-130686 to rats, similar to repetitive administration of GH, significantly increased the fat free mass by an amount almost equal to the gain in body weight.
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