Effects of intracerebroventricular injection of fatty acids on food intake and body weight regulation

Abstract

Nutrient sensing within the hypothalamus plays a critical role in the complex network of signals controlling energy metabolism. We used intracerebroventricular (ICV) injections of the saturated palmitic acid (PA), monounsaturated oleic acid (OA), and polyunsaturated omega‐3 docosahexaenoic acid (DHA) to investigate the effects of various fatty acids on food intake, body weight, and the hypothalamic melanocortin system in rats. Both the OA and DHA groups experienced significant decreases in food intake and body weight when compared to controls. PA injections produced no changes in either food intake or body weight. Expression of POMC, a prominent anorectic neuropeptide, was found to be significantly increased in the OA and DHA groups, whereas POMC expression was essentially unaltered in the PA group. Central administration of a melanocortin receptor antagonist, SHU9119, blocked the effects of OA on food intake and body weight, thus implicating a central role for POMC in mediating the effects of fatty acids. Delineating the mechanisms and signaling pathways through which different fatty acids alter central control of energy metabolism may provide future opportunities for the prevention and treatment of metabolic diseases such as obesity and diabetes. This work was supported by the Minnesota Obesity Center.