Level of corticosterone replacement determines body weight gain in adrenalectomized rats with VMH lesions

Adrenalectomized female rats with lesions of the ventromedial hypothalamus 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 weight gains at all circulating levels of corticosterone, with a significant 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-response curve, and b) both Type I and Type II corticosterone receptors in the brain play a role in hypothalamic obesity.