[Activity of certain redox enzymes of rat liver mitochondria at different levels of dietary vitamin E].

Taking into account the found earlier relation of vitamin E to the ubiquinone functioning and metabolism, the authors studied the enzymic activity of succinate dehydrogenase, NADH-dehydrogenase and cytochrome-c-oxidase--coenzyme Q binding sites of the respiratory chain of the rat liver mitochondria. The experiments were carried out with female rats who received a vitamin-E-deficient diet for 6 months. The enzymic activities and the ubiquinone content in the liver mitochondria of these animals are shown to be considerably lower as compared to the animals received a vitamin E diet; alpha-ocopherol, alpha-tocopheronolactone and ubiquinone 3h after administration manifest a clearly pronounced normalizing effect relative to both the enzymic activity and the ubiquinone content. An assumption is advanced that the effect of alpha-tocopherol and its metabolite is associated with controlling the level of functionally active ubiquinone in the mitochondria. Other mechanisms of the membrane-bound enzymes control by the compounds under study are also discussed in connection with the alpha-tocopherol effect on the mitochondrial membranes.