LEPTIN DECREASES FOOD-INTAKE INDUCED BY MELANIN-CONCENTRATING HORMONE(MCH), GALANIN (GAL) AND NEUROPEPTIDE-Y (NPY) IN THE RAT

Recent evidence suggests that leptin reduces food intake (FI) by actin g at the hypothalamic level. Leptin decreases hypothalamic neuropeptid e Y (NPY), melanin-concentrating hormone (MCH) and galanin (GAL) gene expression in rats. The purpose of the present study was to test the h ypothesis that leptin decreases FI by additionally modulating the acti on of NPY, MCH or GAL in the hypothalamus. Intracerebroventricular (ic v) administration of NPY, MCH or GAL induced FI in satiated rats. A pr ior icy injection of leptin (4 mu g) completely prevented the increase of FI either by MCH, GAL or NPY. These results suggest that modulatio n of post-synaptic actions of MCH, GAL and NPY is one of the mechanism s of leptin signaling in the hypothalamus.