Abstract
In humans, dehydroepiandrosterone and its sulfate ester metabolite DHEA-S are secreted predominantly from the adrenal cortex, and dehydroepiandrosterone is converted to steroid hormones, including androgens and estrogens, and neurosteroid. Dehydroepiandrosterone exerts protective effects against several pathological conditions. Although there are reports on the association between dehydroepiandrosterone and vitamins, the exact relationship between dehydroepiandrosterone and vitamin E remains to be determined. Therefore, we attempted to elucidate the effect of dehydroepiandrosterone on vitamin E status and the expression of various vitamin E-related proteins, including binding proteins, transporters, and cytochrome P450, in vitamin E-deficient rats. Plasma α-tocopherol levels in vitamin E-deficient rats increased in response to dehydroepiandrosterone administration. The expression of hepatic α-tocopherol transfer protein was repressed in vitamin E-deficient rats compared to that in control rats; however, dehydroepiandrosterone administration significantly upregulated this expression. Hepatic expression of CYP4F2, an α-tocopherol metabolizing enzyme, in vitamin E-deficient rats was decreased by dehydroepiandrosterone administration, whereas hepatic expression of ATP-binding cassette transporter A1, an α-tocopherol transporter, was not altered following dehydroepiandrosterone administration. Dehydroepiandrosterone repressed lipid peroxidation in the liver of vitamin E-deficient rats. Therefore, adequate dehydroepiandrosterone supplementation may improve lipid peroxidation under several pathological conditions, and dehydroepiandrosterone may modulate α-tocopherol levels through altered expression of vitamin E-related proteins.