Gastrointestinal hormone upon their chemical structure. Ghrelin is a peptide hormone released from the stomach and liver and is often referred to as the "hunger hormone" since high levels of it are found in individuals that are fasting. Ghrelin agonistic treatments can be used to treat illnesses such as anorexia and loss of appetites in cancer patients. Ghrelin treatments for obesity are still under intense scrutiny and no conclusive evidence has been reached. This hormone stimulates growth hormone release. Amylin controls glucose homeostasis and gastric motility Glucose-dependent insulinotropic polypeptide possesses an acute influence on food intake through its effects on adipocytes Oxyntomodulin
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