Comparison of effects of adrenalectomy and RU-486 in rats given a choice of maintenance diet and fat supplement.

The effects of adrenalectomy (ADX) and the blockade of glucocorticoid receptors by RU-486 on Sprague-Dawley rats given a choice of a maintenance diet and a fat supplement were studied. Adult male rats were given free access to AIN-76A diet only (CON) or AIN-76A diet and a separate dietary fat option for 4 wk (FAT). They were then assigned to one of the following treatments: ADX, sham operation, ADX with corticosterone (CORT) replacement, RU-486 injections, or vehicle injections. Food intake and body weight were monitored daily for an additional 3 wk. ADX decreased caloric intake and weight gain in the FAT group more than in the CON group. RU-486 also decreased caloric and fat option intakes as well as weight gain. ADX, but not RU-486, reduced body fat content, lowered plasma insulin and triglyceride levels, and decreased glucose intolerance. CORT replacement partially prevented the effects of ADX on weight gain and body fat content. The results of this study indicate that ADX has greater effects on weight gain and body fat accumulation than does RU-486.