11 Facts About Ghrelin

Ghrelin is a hormone produced by enteroendocrine cells of the gastrointestinal tract, especially the stomach, and is often called a "hunger hormone" because it increases the drive to eat.

Ghrelin participates in regulation of reward cognition, learning and memory, the sleep-wake cycle, taste sensation, reward behavior, and glucose metabolism.

Ghrelin was discovered after the ghrelin receptor was determined in 1999.

Ghrelin only becomes active when caprylic acid is linked posttranslationally to serine at the 3-position by the enzyme ghrelin O-acyltransferase .

Ghrelin cells are found mainly in the stomach and duodenum, but in the jejunum, lungs, pancreatic islets, gonads, adrenal cortex, placenta, and kidney.

Ghrelin cells are found in oxyntic glands, pyloric glands, and small intestine.

Ghrelin cells are not terminally differentiated in the pancreas: they are progenitor cells that can give rise to A-cells, PP cells and Beta-cells there.

Ghrelin is a participant in regulating the complex process of energy homeostasis which adjusts both energy input – by adjusting hunger signals – and energy output – by adjusting the proportion of energy going to ATP production, fat storage, glycogen storage, and short-term heat loss.

Ghrelin reduces the sensitivity of gastric vagal afferents, so they are less sensitive to gastric distension.

Ghrelin has been linked to inducing appetite and feeding behaviors.

Ghrelin is produced early by the fetal lung and promotes lung growth.