[Vitamin E activity of some alpha-tocopherol derivatives and their effect on the ubiquinone level in rat liver in vitro].

An addition of alpha-tocopherol (I) and its synthetic derivatives (alpha-tocopheryl quinone (II), its short-chained analog (III), alpha-tocopherol lactone (IV), and short-chained alpha-tocopheryl acetate (V)) to the homogenized liver of vitamin E deficient rats resulted in a significant increase of ubiquinone after 2 hour incubation. Activity of the above derivatives (II-V) was not associated directly with their transformation into I or with a noticeable increase of the I content. There is a certain correlation between the chemical structure and the level of vitamin E activity of alpha-tocopherol derivatives that led to an increase in the ubiquinone content and prevented the decrease of tissue respiration and termination of pregnancy in rats.

[Interconversions of ubiquinone and ubichromenol in rat liver under the effect of alpha-tocopherol].

Incubation of ground liver preparation isolated from vitamin E-deficient rats resulted in correlated in time changes of ubiquinone and ubichromenol contents and their ration in tissues. A suggestion is made on the possibility of ubiquinone and ubichromenol interconversions and of the existence of a system controlling (depending on a functional state of the organism) a certain ratio of the quinones contents in animal tissues. Possible biochemical role of ubichromenol in animals is discussed.

[In vitro metabolism of ubiquinone and ubichromenol in the livers of rats with avitaminosis E during individual and combined addition of alpha-tocopherol and phenylalanine].

A maximal incorporation of 2-14C-acetate into ubiquinone and ubichromenol was found within 3 hrs if liver tissue homogenate of E-avitaminous rats was incubated for 4 hrs. Phenylalanine, added to the mixture, stimulated the biosynthesis of ubiquinone and ubichromenol in the liver tissue preparations. alpha-Tocopherol caused an increase in biosynthesis of ubiquinone and a decrease in the rate of ubichromenol biosynthesis within 1 hr and 3 hrs of incubation in vitro.

[Effect of phenylalanine and alpha-tocopherol on ubiquinone and ubichromenol metabolism in the liver of E-avitaminotic rats in vitro].

When incubating the liver pulp of vitamin E-deficiency rats with 2-14C-sodium acetate and phenylalanine for an hour the content and radioactivity of ubiquinone and ubichromenol increase as compared to the control level. In this respect phenylalanine in in a dose of 60 and 120 mumol per 1 g of the liver pulp is most effective. Under conditions of these experiments incubation for 3 h causes no noticable changes in the content and metabolism of ubiquinone and ubichromenol in the liver pulp of vitamin E-deficiency rats as compared to the control level.

[Content of ubiquinone and ubichromenol in rat liver at various levels of vitamin E saturation of the body].

Ubiquinone and ubichromenol content was studied at different levels of organism supply with vitamin E. The content of these substances in the albino rat liver with vitamin E-deficiency is shown to decrease by 16 and 23%, respectively. The intravenous administration of alpha-tocopherol to the vitamin E-deficiency rats causes a gradual 45% increase in the ubiquinone content 4h after which remains at the same level for 8 h; the ubichromenol content 2 h latter is 1.