Ipamorelin, the first selective growth hormone secretagogue

Summary

This study characterized ipamorelin as the first growth hormone secretagogue with high selectivity for GH release without significant effects on ACTH, cortisol, prolactin, or FSH/LH levels. Using in vivo swine models and in vitro rat pituitary cell assays, the authors demonstrated that ipamorelin releases GH with an efficacy and potency comparable to GHRP-6 but with a markedly cleaner endocrine profile.

Key Findings

• Ipamorelin stimulated GH release with potency similar to GHRP-6 in both in vitro pituitary cell assays and in vivo swine models
• Unlike GHRP-6 and other GHRPs, ipamorelin did not significantly affect plasma levels of ACTH, cortisol, prolactin, or other pituitary hormones at GH-releasing doses
• The selectivity profile of ipamorelin was attributed to its distinct receptor binding characteristics at the growth hormone secretagogue receptor