Effects of vitamins E and A on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced lipid peroxidation and other biochemical changes in the rat.

The effects of vitamins A and E on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced lipid peroxidation in the rat were investigated. Vitamin E markedly inhibited microsomal lipid peroxidation (malondialdehyde formation), but had no effect on glutathione peroxidase activity or glutathione (GSH) content, and did not protect against decreased body and liver weights. Furthermore, vitamin E had little effect on TCDD-induced lethality in rats. Vitamin A inhibited lipid peroxidation, elevated the activity of glutathine peroxidase and prevented a TCDD-induced decrease in GSH content in the liver. However, vitamin A did not inhibit the decrease in liver and body weights and provided little protection against TCDD-induced lethality. The activities of aryl hydrocarbon hydroxylase, glutathione-S-transferase (GST) and glutathione reductase (GR) increased after treatment with these two vitamins. Administration of vitamins E and A do not provide significant longterm protection against TCDD-induced lethality although they can prevent TCDD-induced microsomal lipid peroxidation as determined by the thiobarbituric acid assay method.