ADRENALECTOMY LOWERS THE BODY-WEIGHT SET-POINT IN RATS

In order to evaluate the impact of a complete depletion of glucocortic oids on rats' body weight set-point, rats were adrenalectomized, and t heir set-points were estimated before, and after surgery. Body weight set-points were obtained from a quantitative behavioral method based o n the rats' food-hoarding response to weight deficit. Ln addition, bod y fat contents were measured in vivo using a total body electrical con ductivity analyzer (TOBEC). The hoarding of food showed that adrenalec tomized rats had significantly lower body weight set-points than the s ham-operated controls (337 +/- 11 g vs. 385 +/- 8 g) and were al so si gnificantly lighter. TOBEC measurements showed that the sham-operated control rats had a higher body fat content than the adrenalectomized r ats (16.7 +/- 1.1% vs. 10.2 +/- 1.2%). The present study demonstrates that adrenalectomy lowers the body weight set-point in rats, suggestin g that the concentrations of glucocorticoid hormones, and in turn, the hypothalamic corticotrophin releasing hormone (CRH) participates in t he adjustment of the body weight set-point. (C) 1997 Elsevier Science Inc.