Gender differences in adrenal cortex steroid production in SHR/N-corpulent rats

Gender differences in adrenal steroid hormone production and serum steroid hormone levels were compared in the spontaneous hypertensive/NIH-corpulent (cp) rat, which exhibits characteristics of both obesity and non-insulin-dependent diabetes mellitus. The study demonstrated that adrenal gland size correlated with adrenal production and serum levels of steroid hormones. Obese female SHR/N-cp rats were more steroidogenic than male SHR/N-cp rats; the size of their adrenal glands was twice that of the males (70 vs 33 mg). Body weights averaged 666 g for females and 829 g for males. Obese female rats had significantly higher serum concentrations of both corticosterone (827 vs 536 ng/ml) and aldosterone (675 vs 482 pg/ml) than obese male rats. As determined by in vitro assay, adrenal cortex production of corticosterone (2157 vs 1435 ng/30 min) and aldosterone (13.3 vs 9.5 ng/30 min) was significantly higher in obese female than in obese male rats. Adrenal production of testosterone in the in vitro assay was also significantly higher for obese female than male rats; however, adrenal estrogen production in obese rats did not differ significantly. The type of carbohydrate consumed (sucrose > starch) significantly affected serum levels of corticosterone, but not aldosterone, testosterone, or estrogen. Gender differences in adrenal steroid production and serum steroid levels suggest that hyperglycemia in obese SHR/N-cp rats may be, in part, the result of excess adrenal production of steroid hormones.