Vitamin E Activity of γ-Tocopherol in the Rat, Chick and Hamster

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Abstract
The purpose of this study was to reevaluate the vitamin E activity of γ-tocopherol relative to α-tocopherol in several species of animals (literature values range from 1 to 25%). In the prevention of liver necrosis in the rat, d-γ-tocopheryl acetate had a relative potency compared with d-α-tocopheryl acetate of 5.7 ± 1.5%, when computed from individual survival times. When α- and γ-tocopherols were fed as mixtures, comparison of the incidence of liver necrosis indicated a relative activity for γ-tocopherol of 13 to 16%. There was evidence that an interaction between the two tocopherols occurred. In the prevention of chick exudative diathesis, γ-tocopherol had an indicated relative activity of 8 and 9% in two trials. Comparison of the two tocopherols for their ability to prevent chick muscle dystrophy and the accompanying elevation in serum creatine phosphokinase indicated a relative activity of about 10% for γ-tocopherol. In a single experiment with hamsters, the comparison was based on the prevention of testicular degeneration and the maintenance of serum creatine phosphokinase levels. By both criteria, γ-tocopherol showed about 5% activity. On the basis of the more extensive rat and chick experiments, it is concluded that the relative activity of γ-tocopherol is from 6 to 16% that of α-tocopherol.