Ligand for growth hormone secretagogue receptor type 1 (GHSR). Induces the release of growth hormone from the pituitary. Induces adiposity and stimulates gastric acid secretion. Involved in growth regulation (By similarity). Has an appetite-stimulating effect. Expressed in the telencephalon, hypothalamus, pituitary, intestine, liver, spleen and gill, with expression strongest in the intestine. O-octanoylated by GOAT/MBOAT4 (By similarity). O-octanoylation or O-decanoylation is essential for activity. The O-decanoylated form differs in the length of the carbon backbone of the carboxylic acid forming an ester bond with Ser-29 (By similarity). Belongs to the motilin family.