The effect of dehydroepiandrosterone acetate on liver peroxisomal enzyme activities of male and female rats.

The present study is a follow-up to the report that dehydroepiandrosterone (DHEA) acetate treatment in rats stimulated metabolic heat production and suppressed serum triglycerides, adiposity and weight gain without affecting food intake. Activities of peroxisomal fatty acyl-coenzyme (CoA) oxidase and catalase as well as mitochondrial citrate synthase were assayed in liver tissue of 24 young adult male and female Wistar rats fed a nonpurified diet containing 0.6% DHEA (6 g/kg) for 6 wk. DHEA-treated animals gained less weight but had heavier liver weights than did the controls. Hepatic activity of fatty acyl-CoA oxidase of the experimental male and female animal was 1058 and 946% higher, respectively, than that of the controls. For catalase activity, only the female groups were different (30%). Activity of citrate synthase was not affected by DHEA. These data support the hypothesis that the inhibitory effect of DHEA on energy storage as fat is mediated, at least in part, by increased beta-oxidation of fatty acids in peroxisomes. The peroxisomal beta-oxidation pathway is uncoupled from oxidative phosphorylation; electrons are transferred directly to molecular O2 because of cycling of NAD/NADH resulting in the expenditure of chemical energy as heat.