OCCURRENCE OF THE TOCOPHEROLS 801 



of the quantity of this vitamin present in the previous diet. It would seem 

 that the Hver serves to replenish the need of other tissues for tocopherol 

 when the intake of vitamin E is low. 



Further information on the distribution of tocopherol in the tissues of the 

 adult rat can be obtained from the recent report of Quaife and her col- 

 laborators.*"* When 1 mg. of a-tocopherol was fed daily to male rats on a 

 vitamin-E-deficient diet, the highest concentrations were found in the 

 pituitary and adrenal glands (90 and 34 mg. per 100 grams, respectively). 

 Tocopherol in the other tissues varied between 5.85 mg. per 100 grams in the 

 mesenteric fat to 0.70 mg. per 100 milliliters in the blood plasma. The 

 data are summarized in Table 3. 



Apparently ^'itamin E is required by the bird. A considerable amount 

 exists in the yolk of eggs; this quantity varies with the intake in the food.^' 

 Quaife et al.^^ have shown that the hen, like the cow and the human sub- 

 ject, absorbs and deposits a-tocopherol in preference to the other members 

 of the vitamin E group. It was found that, when pure natural a-, y-, or 

 5-tocopherol w^as administered to hens in the form of capsules in doses of 100 

 to 4,000 mg. per week, the tocopherol content of the eggs increased linearly 

 with the logarithm of the dose of the supplement fed. The relative amounts 

 of the 7- and 5-tocopherol found in the eggs were much less than that of the 

 o:-to('opherol deposited in this product. When a-, y-, or 5-tocopherols were 

 administered to the hens at a level of 400 mg. per week, the relative con- 

 centrations of the tocopherols were 24.2, 5.7, and 2.3 mg., respectively, per 

 100 milligrams of the fresh egg. The relative efficiency of transfer of 

 a-tocopherol to the egg was shown to be 22.1%, compared with figures of 

 3.6 and 2.0% for the y- and 5-tocopherols, respectively. 



There is no evidence of an in vivo transformation of one tocopherol to 

 another type. Thus, the hens fed steadily increasing doses of 5-tocopherol 

 produced eggs w^ith a correspondingly increased proportion of 5-tocopherol. 

 In the case of the hens fed 7-tocopherol at higher levels, eggs containing 

 more than 90% of the total tocopherols as 7-tocopherol were reported. 



The livers of normal cattle and horses are rich in vitamin E,^'' while 

 appreciable amounts have also been found in the livers of monkeys and of 

 man.^^ According to Abderhalden,^' cow milk is an exceedingly poor source 

 of vitamin E. The average value reported was 0.061 milligram per cent. 

 When the cow's fodder was supplemented with a-tocopherol,^^ increased 

 amounts of tocopherol were secreted in the milk; on the other hand, when 

 the supplement was made up of 90% of 7- and 5-tocopherol, only slight in- 

 creases in milk tocopherol were noted. In the first case, the milk tocopherol 



•^ M. L. Quaife, W. J. Swaiison, M. Y. Dju, and P. L. Harris, Ann. New York Acad. 

 Set., 52, 300-305 (1949). 



" G. L. Barnam, J. Xutrition, 9, 621-635 (1935). 



"> P. Karrer, W. Jaeger, and II. Keller, Heir. Chim. Acta, 23, 464-465 (1940). 



" R. Aljderhalden, Biochem. Z., 318, 47-53 (1948). 



