Glutathione peroxidase in mouse tissues: Effect of age and dietary vitamin E

Female weanling mice were fed one of the following four diets: (1) vitamin E deficient; (2) 30 ppm vitamin E supplemented; (3) 300 ppm vitamin E supplemented; or (4) 30 ppm DPPD (N,N'-diphenyl-phenylenediamine) supplemented diet. Spleen, lung, kidney, blood, liver and uterus were assayed for glutathione peroxidase (GSH-Px) activity at 2, 5, 9 and 12 months of age. In addition lung, blood and liver were assayed at 18 months of age. Dietary supplementation of vitamin E had an effect on blood GSH-Px activity at 18 months of age where it was higher with higher levels of vitamin E supplementation. However, vitamin E and DPPD supplementation did not affect GSH-Px activity of other tissues assayed. No age-related increase in enzyme activity was seen in spleen, uterus, liver, and lung. An increase in GSH-Px activity was observed in the kidney of all dietary groups by 12 months of age and in the blood of the vitamin E supplemented dietary groups by 18 months of age. Results suggest that GSH-Px activity of some tissues increase in old age, but in some cases the increase is dependent on the presence of vitamin E in the diet.