Glucocorticoid and Estrogen Administration in Weanling Rats with Hypothalamic Obesity

The development of obesity in weanling rats with ventromedial hypothalamic lesions has been shown previously to be independent of hyperphagia, hyperinsulinemia and growth hormone deficiency. The present experiments were designed to study hypothalamic obesity in rats treated with pharmacologic doses of estrogens or glucocorticoids. Weanling rats with or without hypothalamic lesions were injected subcutaneously with methylprednisolone acetate (8 mg/kg daily) or with a single 1 mg dose of polyestradiol phosphate. After two weeks the rats were sacrificed. The glucocorticoid injections produced hyperinsulinemia and completely blocked the obesity and metabolic changes usually seen after hypothalamic lesions. The estrogen treatment increased weight gain and basal lipogenesis from glucose in vitro but did not in any way inhibit the development of the changes seen after hypothalamic lesions.