MEDIALBASAL HYPOTHALAMIC DEAFFERENTATION MODULATES FEEDING RESPONSE TO INSULIN IN RATS

Medialbasal hypothalamic (MBH) deafferentation induces hypothalamic ob esity accompanied by hyperphagia and hyperinsulinemia. Insulin is esse ntial in developing and maintaining obesity, but the role of insulin i n food intake in hypothalamic obesity is still unclear. The present st udy demonstrated that exogenous insulin increased food intake dose rel atedly in MBH deafferented diabetic rats without developing hypoglycem ia. Insulin administrations suppressed hyperphagia in the sham-operate d diabetic rats. In contrast, in the MBH deafferented diabetic rats, i nsulin increased food intake in sow-related manner concomitant with a greater increased body weight gain than the sham-operated diabetic rat s. The blood glucose levels of the MBH deafferented diabetic rats were at all time higher than those of the sham-operated diabetic rats and were hyperglycemic throughout the insulin treatment. These data indica te that insulin action on food intake mediated through the central ner vous system is modulated by MBH deafferentation. This modulated insuli n action may contribute to the pathogenesis on obesity in MBH deaffere nted animals.