VITAMIN-E REDUCES GLUCOCORTICOID-INDUCED GROWTH-INHIBITION AND LIPID-PEROXIDATION IN RATS

This experiment was conducted to study the effects of vitamin E on gro wth inhibition and lipid peroxidation in rats treated with different l evels of corticosterone (CTC). Rats(Sprague-Dawley strain, 5 weeks of age) were divided into two groups: control group receiving a basal die t containing 60 mg DL-alpha-tocopheryl acetate/kg diet, and vitamin E group receiving the same diet supplemented with 5,000 mg tocopherol. A fter 6 days, rats of both diet groups were further divided into three groups by dose levels of CTC treatment (0, 25, and 100 mg CTC/kg body weight/d). CTC was administered to the rats by subcutaneous injection for 4d. Growth was dose-dependently inhibited by the CTC treatment. Fe eding the vitamin E diet significantly (p<0.05) improved growth retard ation. Feed efficiency was lowered by CTC treatment, while this was si gnificantly (p<0.05) minimized by feeding the vitamin E diet. Lipid pe roxidation (TBARS) in the liver was elevated by the CTC treatment (p<0 .001) when the rats were fed the basal diet. The increment in TBARS wa s significantly (p<0.001) reduced by vitamin E. The activities of glut athione S-transferase (GST) and superoxide dismutase (SOD) were signif icantly reduced by the CTC treatment in a dose-dependent manner in bot h dietary groups. Feeding vitamin E significantly (p<0.001) improved t he reduction in GST activity. The SOD activity showed some tendency. T he present results demonstrate the effectiveness of vitamin E in impro ving growth retardation in glucocorticoid-treated rats and suggest tha t reductions in increased lipid peroxidation due to CTC may be an impo rtant factor of the action of vitamin E.