Measurements of lipid peroxidation and α-tocopherol destruction in vitro and in vivo and their significance in connexion with the biological function of vitamin E

I. Lipid peroxides have been measured by a micro-iodimetric method in pancreas, lung, adrenal, leg muscle, spleen, brain, small intestine and uterus of vitamin E-deficient and vitamin E-supplemented rats. There were no differences due to the vitamin E status of the rats. 2. The decay of [14C]~-a-tocopherol in peroxidizing methyl oleate, maize oil methyl esters and cod-liver oil methyl esters was studied at goo. When the decrease in tocopherol was plotted against increase in peroxide value for each ester preparation, it was found that, the greater the degree of unsaturation of the substrate, the less was the amount of tocopherol destroyed at any peroxide value attained before the end of the induction period. When the decay of tocopherol was plotted against time, however, the greater the degree of unsaturation of the substrate, the greater was the amount of tocopherol destroyed at any given time before the end of the induction period. 3. The significance of these results in connexion with the biological function of vitamin E is discussed.