Adrenalectomy Lowers the Body Weight Set-Point in Rats

Abstract

Gosselin, C. and M. Cabanac. Adrenalectomy lowers the body weight set-point in rats. Physiol Behav 62(3) 519–523, 1997.—In order to evaluate the impact of a complete depletion of glucocorticoids on rats’ body weight set-point, rats were adrenalectomized, and their set-points were estimated before, and after surgery. Body weight set-points were obtained from a quantitative behavioral method based on the rats’ food-hoarding response to weight deficit. In addition, body fat contents were measured in vivo using a total body electrical conductivity analyzer (TOBEC). The hoarding of food showed that adrenalectomized rats had significantly lower body weight set-points than the sham-operated controls (337 ± 11 g vs. 385 ± 8 g) and were also significantly lighter. TOBEC measurements showed that the sham-operated control rats had a higher body fat content than the adrenalectomized rats (16.7 ± 1.1% vs. 10.2 ± 1.2%). The present study demonstrates that adrenalectomy lowers the body weight set-point in rats, suggesting that the concentrations of glucocorticoid hormones, and in turn, the hypothalamic corticotrophin releasing hormone (CRH) participates in the adjustment of the body weight set-point.