Ghrelin was originally discovered as a preprohormone that stimulates the release of growth hormone from the anterior pituitary. Recent studies have shown that ghrelin, in concert with other hormones, helps to control both appetite and energy balance. The synthesis of ghrelin takes place predominantly in epithelial cells of the stomach, although it is also produced in smaller quantities in the placenta, kidney, pituitary and hypothalamus.Ghrelin is an endogenous ligand for the growth hormone secretagogue receptor and is involved in regulating growth hormone release from the pituitary. It has an appetite stimulating effect, induces adiposity, and stimulates gastric acid secretion, and it is involved in growth regulation.