Harnessing Gut Hormones Could Help Control Body Fat

The stomach and intestines secrete hormones that sense food intake, control appetite and help regulate metabolic rate. These hormones include peptide YY, pancreatic polypeptide, glucagon-like peptide, ghrelin, amylin and cholecystokinin. For example, during caloric restriction (i.e., dieting), the gut releases ghrelin— which activates fat metabolism, free radical formation and uncoupling proteins in the cells of the hypothalamus, which trigger hunger. This process activates a variety of energy control pathways in the brain that increase food intake and slow metabolic rate. This explains why some people stop losing weight on a diet and exercise program after several months, even though they are eating less and burning more calories than they did before they started the program. Pharmaceutical companies are attempting to develop drugs that will modify the action of gut hormones, which might suppress appetite and increase caloric expenditure. (Pharmacology & Therapeutics, 124: 44-56, 2009)