Synthetic Ghrelin Receptor Agonism via Growth Hormone-Releasing Peptide-2 (GHRP-2) Promotes Short-Term Hyperphagia and Escalated Caloric Intake in Healthy Men

Journal Context: The Journal of Clinical Endocrinology & Metabolism | Identifiers: DOI: 10.1210/jc.2004-1719 / PMID: 15699539

Principal Investigators: Laferrère, B., Abraham, C., Russell, C. D., & Bowers, C. Y. (Obesity Research Center, St. Luke's-Roosevelt Hospital Center / Columbia University)

Methodology: A randomized, cross-over human clinical trial enrolling lean, healthy male volunteers. Subjects were administered a continuous subcutaneous infusion of GHRP-2 ($1\ \mu\text{g/kg/h}$) or a matching saline control for 270 minutes before being granted ad libitum access to a buffet-style meal to calculate exact weight and caloric consumption spikes.

Key Findings: Mirroring the neurological behavior of native gut ghrelin, human subjects consumed $35.9\% \pm 10.9\%$ more total calories when infused with GHRP-2 compared to the saline arm ($P = 0.008$). This hyperphagic effect occurred concurrently with a massive, statistically significant surge in serum growth hormone levels ($\text{AUC}\ 5550 \pm 1090\ \mu\text{g/L/240 min}$ vs. $412 \pm 161\ \mu\text{g/L/240 min}$), proving that GHRP-2 simultaneously controls both somatotroph secretion and central appetite regulation in humans.