Topic summary
Ghrelin
Ghrelin (; or lenomorelin, INN) is a hormone primarily produced by enteroendocrine cells of the gastrointestinal tract, especially the stomach, and is also dubbed the "hunger hormone" because it increases the drive to eat. Blood levels of ghrelin are highest before meals when hungry, returning to lower levels after mealtimes. Ghrelin may help prepare for food intake by increasing gastric motility and stimulating the secretion of gastric acid.
Ghrelin activates cells in the anterior pituitary gland and hypothalamicarcuate nucleus, including neuropeptide Yneurons that initiate appetite. Ghrelin stimulates brain structures having a specific receptor – the growth hormonesecretagogue receptor 1A (GHSR-1A). Ghrelin also participates in regulation of reward cognition, learning and memory, the sleep-wake cycle, taste sensation, reward behavior, and glucose metabolism.