INTRACEREBROVENTRICULAR NEUROPEPTIDE-Y PRODUCES HYPERINSULINEMIA IN THE PRESENCE AND ABSENCE OF FOOD

Acute administration of neuropeptide Y into the hypothalamus or cerebr al ventricles produces hyperphagia and hyperinsulinemia. However, it i s not known to what extent the hyperinsulinemia depends on the food in take. Consequently, serum insulin and glucose, as well as food and wat er consumption, were measured over 3 h, following injection of 1-20 mu g neuropeptide Y into the third ventricle of adult female rats. In th e presence of food, 1-10 mu g neuropeptide Y produced a dose-dependent increase in food and water intake and serum insulin. Insulin levels w ere closely correlated with the quantity of food ingested. In the abse nce of food, 1-20 mu g neuropeptide Y produced a dose-dependent increa se in water intake, whereas 1-5 mu g produced a dose-dependent increas e in serum insulin. We concluded that ICV neuropeptide Y can stimulate insulin secretion even at low doses and this response does not comple tely depend on food intake.