Effects of adrenalectomy and corticosterone administration on hypothalamic obesity in rats

Abstract

The role of adrenal hormones in hypothalamic hyperphagia and obesity was assessed. Ventromedial hypothalamic (VMH) or sham lesions were produced either 15 days before or after adrenalectomy (ADX) or sham adrenalectomy in rats in a completely counterbalanced design (experiment 1). Body weight and food intake were recorded for 30 days after the 2nd surgery. Adrenalectomy in obese VMH animals eliminated all excess weight gain and decreased food intake to below the level of all control groups. VMH lesions in ADX animals did not produce the characteristic weight gain associated with ventromedial hypothalamic damage; this group was not significantly different from animals with sham lesions in body weight or food intake. In experiment 2, the administration of corticosterone resulted in a marked increase in the rate of weight gain in ADX-VMH animals, and the withdrawal of the hormone was followed by weight loss. Adrenal glucocorticoid hormones are necessary for the development and maintenance of VMH hyperphagia and obesity.