LEVEL OF CORTICOSTERONE REPLACEMENT DETERMINES BODY-WEIGHT GAIN IN ADRENALECTOMIZED RATS WITH VMH LESIONS

Adrenalectomized female rats with lesions of the ventromedial hypothal amus or sham lesions were given SC implants of wax pellets or a fused mixture of corticosterone-cholesterol (40, 75, or 130% by weight). In animals with sham lesions, high dosages of corticosterone proved to be catabolic (r = -0.61 between plasma corticosterone and weight change) . In marked contrast, animals with VMH lesions displayed substantial w eight gains at all circulating levels of corticosterone, with a signif icant positive correlation (r = +0.48) between these two variables. It is concluded that: a) damage to the basomedial hypothalamus alters an organism's response to corticosterone at both ends of the dose-respon se curve, and b) both Type I and Type II corticosterone receptors in t he brain play a role in hypothalamic obesity.