Ghrelin

A 28-amino-acid orexigenic (appetite-stimulating) peptide produced primarily by X/A-like cells in the gastric fundus. The endogenous ligand for the growth hormone secretagogue receptor-1a (GHS-R1a). Stimulates GH release, appetite, and fat storage. GHRP peptides (GHRP-2, GHRP-6, Ipamorelin, Hexarelin) are synthetic agonists designed to mimic or improve upon ghrelin's GH-secretagogue properties.