Roles of Gut Hormones in the Regulation of Food Intake and Body Weight

Abstract

The gastrointestinal tract is extremely rich in endocrine cells and secretes a myriad of hormones, including ghrelin, glucagon-like peptide 1(GLP1), gastric inhibitory peptide (GIP), cholecystokinin (CCK), amylin, peptide YY (PYY), oxyntomodulin, and leptin. Mechanical distention of the stomach elicits mechanoreceptors within the gastric wall sensing tension, stretch, and volume, which then send brain signals through vagal and spinal sensory nerves. Both stomach and gut are tightly connected with the central nervous system where the fullness sensation is elaborated. Peripheral signaling hormones regulate appetite in the hypothalamic arcuate nucleus through anorexigenic and orexigenic signals. The gut–hindbrain axis is sufficient to drive the satiation sensation, although hindbrain also communicates with the forebrain where sensory and cognitive processes linked to meal anticipation and learned associations play a relevant role in the anticipation of food reward and pleasure. We report an overview of the intestinal mechanisms regulating satiety and body weight with particular emphasis to the effects of drugs and bariatric/metabolic surgery on gut hormonal secretion.