Effects of Vitamin E and Selenium on Rubidium-86 Uptake by Rat Liver Slices

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Abstract
Oral administration of vitamin E or selenium to rats fed a vitamin E-deficient casein diet stimulated by an average of 128 or 34%, respectively, the uptake of rubidium-86 by liver slices that had been previously depleted of their potassium by cooling. Inclusion of 100 ppm of dl-α-tocopheryl acetate or 0.30 ppm Se in the vitamin E-deficient diet resulted in 50 to 202 and 17 to 97% enhancements in Rb uptake by rat liver slices as compared to the unsupplemented controls. The stimulation of Rb transport seen in liver slices as a result of vitamin E or Se supplementation in the diet was not observed in kidney slices or hemidiaphragms. Addition of vitamin E to the deficient diet did not increase Rb influx in erythrocytes. Lipid peroxide formation as estimated by the thiobarbituric acid reagent was very slight in the slices either before or after incubation and no correlation was noted between ability to take up Rb and the amount of peroixde present. There was no difference in (Na+-K+)-activated adenosine triphosphatase assayed in whole liver homogenates from rats fed diets containing E or Se or from rats fed the deficient diet. Liver slices from deficient rats which showed the defect in Rb uptake were able to maintain respiration over a 90-minute incubation in the Warburg apparatus if the slices were never allowed to cool, but similar slices suffered a severe decline in respiratory activity during the same time interval if they were preincubated in the cold. It is suggested that vitamin E and Se may have roles in maintaining transcellular cation gradients by stabilizing membrane structures.