ROLE OF HYPOTHALAMIC NEUROPEPTIDE-Y GENE-EXPRESSION IN BODY-WEIGHT REGULATION

Hypothalamic neuropeptide Y (NPY) may be involved in the hyperphagia t hat follows food deprivation associated with significant weight loss. However, it is unclear whether NPY is involved in body weight regulati on under more physiological circumstances. Consequently, we measured b ody weight, food intake, arcuate nucleus (ARC) NPY mRNA, serum glucose , and insulin in male Wistar rats after 48 h of food deprivation and v arious refeeding protocols. Food deprivation produced a twofold increa se in NPY mRNA, whereas 3 days of ad libitum refeeding returned body w eight and NPY mRNA to control. If hyperphagia was prevented for 5 days during refeeding, then neither body weight nor NPY mRNA normalized. T here were strong negative correlations between ARC NPY mRNA and both l oss of body weight and serum insulin levels. These data suggest that h ypothalamic NPY gene expression plays a role in control of body weight under physiological conditions. The data further suggest that NPY mRN A may be decreased by peripheral insulin levels.