Ghrelin capacity for food but also dramatically lowers ghrelin levels compared to both lean controls and those that lost weight through dieting alone. However, studies are conflicting as to whether or not ghrelin levels return to nearly normal with gastric bypass patients in the long term after weight loss has stabilized. Bariatric surgeries involving vertical-sleeve gastrectomy reduce plasma ghrelin levels by about 60% in the long term. Ghrelin plasma concentration increases with age and this may contribute to the tendency for weight gain as people age. Ghrelin Ghrelin (pronounced ), the "hunger hormone", also known as lenomorelin (INN), is a peptide
Ghrelin hormone secretagogue receptor (GHS-R), is found on the same cells in the brain as the receptor for leptin, the satiety hormone that has opposite effects from ghrelin. Ghrelin also plays an important role in regulating "reward perception" in dopamine neurons that link the ventral tegmental area to the nucleus accumbens (a site that plays a role in processing sexual desire, reward, and reinforcement, and in developing addictions) through its colocalized receptors and interaction with dopamine and acetylcholine. Ghrelin is encoded by the "GHRL" gene and is presumably produced from the cleavage of the prepropeptide ghrelin/obestatin. Full-length preproghrelin is homologous to