Vitamin E and stress

Abstract

1. The metabolism of small amounts of [5-Me-¹⁴C]D-α-tocopherol and [5-Me-³H]D-α- tocopherol has been studied in the vitamin E-deficient chick. Small doses of the labelled tocopherol were given to chicks, which were then subjected to stress by giving them diets formulated to produce encephalomalacia, exudative diathesis or muscular dystrophy.2. Tocopherol concentrations in the cerebella and brains of chicks with incipient encephalomacia were the same as those in normal chicks in which the dietary fat stress was absent.3. α-Tocopherol delayed the onset of encephalomalacia by a mean value of 3.5 days when its concentration in the cerebellum was about 2 × 10⁻⁷g/g of lipid. This concentration is considerably below the usual effective concentrations of antioxidants in vitro.4. Selenium deficiency, under conditions leading to a high incidence of exudative diathesis, was not associated with lowered tocopherol levels and did not result in detectable destruction of tocopherol.5. Nor was there any destruction of tocopherol or significant effect on its metabolism in the processes leading to muscular dystrophy: on the contrary, the affected muscles of dystrophic chicks, which had received a diet deficient in sulphur amino acids, contained significantly more tocopherol than muscles from control birds.6. These results do not support the hypothesis that lipid peroxidation is a causative process in the aetiology of vitamin E-deficiency diseases in the chick. The relationships between unsaturated lipid, Se, sulphur amino acids and tocopherol in the chick require further exploration.