Growth hormone secretagogues: characterization, efficacy, and minimal bioactive conformation.
McDowell. R S RS; Elias. K A KA; Stanley. M S MS; Burdick. D J DJ; Burnier. J P JP; Chan. K S KS; Fairbrother. W J WJ; Hammonds. R G RG; Ingle. G S GS; Jacobsen. N E NE; Mortensen. D L DL; Rawson. T E TE; Won. W B WB; Clark. R G RG; Somers. T C TC
Key Findings
- Modified GHRP‑2 analogs are the smallest (<500 Da) and most potent GH secretagogues reported.
- Intermittent dosing in rodents produced measurable anabolic (muscle‑building) effects.
- NMR analysis revealed the bioactive 3‑D conformation of a highly potent cyclic GHRP‑2 analog.
Practical Outcomes
- For biohackers, this work confirms that GHRP‑2 and its tiny analogs can robustly stimulate growth hormone and may work well with intermittent dosing schedules. However, the data are limited to cell studies and rodents, so human dosing protocols remain untested. The structural insights could guide the creation of new, more efficient secretagogues, but practical use still requires clinical validation.
Summary
Scientists reshaped a growth‑hormone‑releasing peptide (GHRP‑2) to make it even smaller and more powerful. In lab tests and animal studies the new versions triggered strong GH release and helped build muscle when given intermittently. They also mapped the 3‑D shape of the best‑working version, giving clues for designing even better low‑weight secretagogues.
Abstract
Another class of growth hormone (GH) secretagogues has been discovered by altering the backbone structure of a flexible linear GH-releasing peptide (GHRP). In vitro and in vivo characterization confirms these GH secretagogues as the most potent and smallest (M(r) < 500) reported. Anabolic efficacy is demonstrated in rodents with intermittent delivery. A convergent model of the bioactive conformation of GHRPs is developed and is supported by the NMR structure of a highly potent cyclic analog of GHRP-2. The model and functional data provide a logical framework for the further design of low-molecular weight secretagogues and illustrate the utility of an interdisciplinary approach to elucidating potential bound-state conformations of flexible peptide ligands.
Study Information
pubmed
1995
1995-11-21T00:00:00.000Z
10.1073/pnas.92.24.11165