Gastrointestinal regulation of food intake

Abstract

The gastrointestinal tract regulates food intake by sending and receiving signals from the brain both through humoral and neural pathways. This system works efficiently because body weight remains remarkably constant over time despite the slight tendency to gain weight as some individual's age. Ghrelin, a peptide secreted by the stomach, promotes food intake and is located ideally to monitor the volume of food and liquid ingested. Cholecystokinin is released by enteroendocrine cells of the duodenum postprandially and plays an important role in the secretion of pancreatic enzymes and the contraction of the gallbladder to release bile into the duodenum to aid digestion and nutrient absorption. Additionally, cholecystokinin is a satiety signal that appears to play a role in the regulation of food intake. Apolipoprotein AIV (apo AIV) might be an important signal in regulating food intake and the absorption of fat. It appears to participate in the packaging and secretion of chylomicrons. Apo AIV probably works peripherally and centrally to inhibit food intake. When nutrients reach the lower small intestine, they stimulate the secretion of peptide YY (PYY), glucagon-like peptide-1, and potentially other signals as well. Their function is to simultaneously reduce food intake and gastric emptying. © 2006 Humana Press Inc.