The gut hormone signalling to the brain under fasted (a) and fed states (b). (a) During the fasting/preprandial state, ghrelin release from the stomach acts upon the ARC and vagus to stimulate hunger. (b) In the postprandial state, release of anorectic hormones, PYY, GLP-1, OXM, and PP from intestine act upon the ARC, brainstem, and vagus to cause satiety. ARC, arcuate nucleus; NPY/AgRP, neuropeptide Y and agouti related peptide; POMC/CART, pro-opiomelanocortin, and cocaine- and amphetamine-regulated transcript; PVN, paraventricular nucleus; GLP-1, glucagon-like peptide-1; PP, pancreatic polypeptide; PYY, peptide YY; OXM, oxyntomodulin.
