INSULIN ACTS ON THE HYPOTHALAMIC GLUCOSE-FACILITATED NEURONS TO INDUCE HYPERGLYCEMIA AND HYPERINSULINEMIA IN THE RAT

Microinjection of insulin (0.04-0.12 IU/mu-l) into the anterior hypothalamus or the lateral hypothalamus, but not the vertromedial hypothalamus of the rat brain, caused a dose-dependent rise in blood glucose and in serum insulin. The majority (71.5%) of the glucose-facilitated neurons recorded in the lateral hypothalamic area were excited by intracerebral injection of insulin. The data indicate that insulin acts on the hypothalamic glucose-facilitated neurons to induce hyperglycemia and hyperinsulinemia. It is unknown whether insulin normally reaches the hypothalamic area, or how it might do so.