ghrelin

1. (biochemistry) A peptide hormone, secreted in the stomach when empty, that increases appetite and secretion of growth hormone from the pituitary gland.Examples: "We designate the GH-releasing peptide ‘ghrelin’ (ghre is the Proto-Indo-European root of the word ‘grow’)."; "Both human and rat ghrelins are 28 amino acid peptides, in which Ser3 is modified by a fatty acid, primarily n-octanoic acid."; "[W]hen you increase ghrelin levels, you stimulate that growth hormone to kick in, and growth hormone builds you not only up but out as well. Your stomach secretes ghrelin in pulses every half hour, sending subtle chemical impulses to your brain—almost like subliminal biological messages (carrot cake, carrot cake, carrot cake)."uncountableusually