Ghrelin Ghrelin Ghrelin (pronounced ), the "hunger hormone", also known as lenomorelin (INN), is a peptide hormone produced by ghrelinergic cells in the gastrointestinal tract that functions as a neuropeptide in the central nervous system. Besides regulating appetite, ghrelin also plays a significant role in regulating the distribution and rate of use of energy. When the stomach is empty, ghrelin is secreted. When the stomach is stretched, secretion stops. It acts on hypothalamic brain cells both to increase hunger, and to increase gastric acid secretion and gastrointestinal motility to prepare the body for food intake. The receptor for ghrelin, the ghrelin/growth
Growth hormone secretagogue receptor in the heart. Two identified transcript variants are expressed in several tissues and are evolutionary conserved in fish and swine. One transcript, 1a, excises an intron and encodes the functional protein; this protein is the receptor for the ghrelin ligand and defines a neuroendocrine pathway for growth hormone release. The second transcript (1b) retains the intron and does not function as a receptor for ghrelin; however, it may function to attenuate activity of isoform 1a. GHS-R1a falls into G-protein-coupled receptor (GPCR) family. Previous studies have shown that GPCRs can form heterodimers, or functional receptor pairs with other types of G-protein