DIETARY VITAMIN-E AND SELENIUM EFFECTS ON RESISTANCE TO OXIDATIVE STRESS IN RAT-LIVER MITOCHONDRIA

Mitochondria-rich fractions isolated from livers of rats fed diets dif fering in their vitamin E (E) and/or selenium (Se) contents were subje cted to NADPH/ADP/Fe3+-dependent assays of lipid peroxidation. Additio n of GSH resulted in an inhibition, or lag period, of lipid peroxidati on in mitochondria from rats supplemented with E. This effect was inde pendent of the Se status of the rats. Addition of GSH + GSSG did not p otentiate the lag period over that observed with GSH alone. Significan t changes in mitochondrial alpha-TH during lipid peroxidation, either in the presence or absence of GSH, were not observed. Total protein th iol (PrSH) content of native mitochondria was lower in rats fed a diet deficient in both E and Se, compared to the other dietary groups. Add ition of GSH or GSH + GSSG maintained mitochondrial PrSH at higher lev els during lipid peroxidation than in control assays without added GSH /GSSG. Addition of GSSG alone decreased PrSH in mitochondria prepared from all rats regardless of their E or Se status. Reduced ubiquinone-g (U-9) and the % of total U-9 and U-10 in the reduced form were signif icantly decreased in liver tissue from rats fed the diet deficient in both E and Se.