Greek, leptos = thin) a polypeptide hormone produced in the gastrointestinal tract (stomach) that stimulates release of growth hormone from the anterior pituitary. Hormone which probably has a role in regulating appetite and energy balance. (More? Endocrine Other Endocrine Notes | Meier U, Gressner AM. Endocrine regulation of energy metabolism: review of pathobiochemical and clinical chemical aspects of leptin, ghrelin, adiponectin, and resistin. Clin Chem. 2004 Sep;50(9):1511-25.

a hormone produced by stomach cells; "ghrelin is thought to increase feelings of hunger"

A stomach hormone that has significant effects on appetite and energy balance.