Ghrelin is the ligand for growth hormone secretagogue receptor type 1 (GHSR). Induces the release of growth hormone from the pituitary. Has an appetite-stimulating effect, induces adiposity and stimulates gastric acid secretion. Involved in growth regulation (By similarity). Obestatin may be the ligand for GPR39. May have an appetite-reducing effect resulting in decreased food intake. May reduce gastric emptying activity and jejunal motility (By similarity). O-octanoylated by GOAT/MBOAT4 (By similarity). O-octanoylation is essential for ghrelin activity. Amidation of Leu-98 is essential for obestatin activity. Belongs to the motilin family. Gut feelings - Issue 66 of January 2006