Vitamin E and stress

Abstract

1. Vitamin E-deficient rats were found to be more susceptible than vitamin E-supplemented controls to the toxic effects of hyperbaric oxygen (60 lb/in.2 for 20 min). This agrees with the findings of other workers. 2. Hyperbaric O2 treatment did not increase the metabolic destruction of a small amount (46.65 μg) of [14C-5-Me]D-α-tocopherol given to adult vitamin E-deficient rats 24 h previously. The O2 treatment also did not affect the soluble sulphydryl compounds and ascorbic acid of rat liver, nor the percentag haemolysis in vivo of rat blood. 3. Hyperbaric O2 treatment did not increase the true lipid peroxide content of rat brain, compared to control rats treated with hyperbaric air, which has no toxic effects. Increases in ‘lipid peroxidation’ reported by previous workers are considered to have been due to the use of inadequate controls (untreated rats) and of in vitro techniques that are open to criticism. 4. The toxic effects of hyperbaric O2 in the vitamin E-deficient rat cannot be attributed to peroxidation in vivo. 5. Vitamin E was not found to protect rats against the effects of reduced O2 tension (anoxic anoxia). This finding contrasts with some reports by earlier workers. Reduced O2 tension had no effect on the metabolism of radioactive tocopherol, on blood haemolysis in vivo, or on the soluble sulphydryl compounds and ascorbic acid of liver.