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The Prophylactic Requirement of the Rat for Alpha Tocopherol¹

Two Text Figures and One Plate (Four Figures)

Institute of Experimental Biology, University of California, Berkeley

1. Growth and reproduction were studied for 16 months in male and female rats maintained from weaning on a vitamin E low diet (Diet 427), and supplemented with three levels of alpha tocopheryl acetate; the levels were 0.10 mg., 0.25 mg., and 0.75 mg. six times weekly.

2. The tocopherol requirement for normality of the striated musculature and for growth in the case of both sexes is less than 0.10 mg. daily.

3. As regards the males, the 0.10-mg. level was inadequate for the preservation of fertility beyond the fifth month. The 0.25-mg. level was adequate for normal reproduction during approximately the first 9 months of life, but proved inadequate for the subsequent maintenance of fertility. The highest level of tocopherol (0.75 mg. daily) maintained normal testes and fertility during the entire experimental period of 16 months.

4. As regards the females, those receiving 0.10 mg. daily were able to give birth to living young even in their third gestation which was completed between the cleventh and twelfth months of age. By the eighteenth month orange-brown pigmentation of the uterus supervened in all animals receiving 0.10 mg. and 0.25 mg. daily dosage but was absent in the group receiving 0.75 mg.

5. As regards the suckling young, in contrast to the adult female, all those born from mothers receiving 0.10 mg. daily dosage exhibited muscular dystrophy with a high mortality rate in the third week of life. Those born from mothers receiving 0.25 mg. daily dosage exhibited a lessened incidence of dystrophy with a lowered mortality rate until the third breeding when all young were paralyzed and died as was the case in litters from mothers receiving 0.10 mg. All young from mothers receiving 0.75 mg. daily dosage were normal in the first two breedings, but in the third gestation there was a slight incidence of dystrophy with complete recovery by the thirtieth day of life.

Manuscript received 7 July 1943.