Comparative effectiveness of vitamin D3 and dietary vitamin E on peroxidation of lipids and enzymes of the hepatic antioxidant system in Sprague--Dawley rats.

The vitamin D-endocrine system has mostly been studied for its role in calcium and phosphorus metabolism and its possible role as an antioxidant has been neglected. This study attempts to elucidate the antioxidative properties of the prohormone with respect to vitamin E, a membrane antioxidant. Results herein show that D3 treatment brought about similar reduction in the extent of lipid peroxidation and induction in superoxide dismutase (SOD) activity, as with vitamin E supplementation. While selenium dependent glutathione peroxidase (Sedep. GPx) activity reflected no change with vitamin D3 treatment, total GPx activity was more significantly influenced by vitamin D3 than by vitamin E. The glutathione (GSH) content in the experimental rats also reflected similar changes. Vitamin E supplementation caused 8.57% increase in glutathione reductase (GR) activity, while vitamin D3 decreased the concerned enzymes activity by 11.11%. Vitamin D3 treatment also caused 25% increase in glucose 6-phosphate dehydrogenase (G6PD) activity. These data thus suggest that vitamin D3 may function as an antioxidant in the liver in vivo and illustrate an effectiveness higher than that observed with vitamin E supplementation.