FACTORS ALTERING CONCENTRATION OF CAROTENOIDS 511 



mg. of a-tocopherol daily. On the other hand, Quaife and Harris 958 re- 

 ported serum tocopherol values of 1.72 milligram per cent and 1.68 milli- 

 gram per cent for rats whose ration was supplemented with vitamin E 

 at a level of 12 mg./week, and which were subjected to stress or were free 

 from stress, respectively. On the other hand, rats which were vitamin E- 

 deficient and were subjected to similar experimental conditions showed a 

 zero value for plasma tocopherol. 



b. General Physiologic Factors Related to the Level of Plasma To- 

 copherols, (a) Relation to Ingested Tocopherol. There can be no doubt 

 that the administration of tocopherol to animals and to man in sufficiently 

 large doses results in augmented levels of this component in the blood 

 plasma. Quaife et a 7 . 136 studied the effect of 500 mg. doses of d-a- and d-y- 

 tocopherols on the levels of serum tocopherols of normal human adults. 

 It was shown that the peak values were not reached until a period of six 

 hours had elapsed; the tocopherol levels in the blood were still elevated 

 twenty-four hours after the supplements were given. These results are 

 charted in Figure 11. 



Meunier and co-workers 957 found a significant decrease in plasma to- 

 copherol when cod-liver oil was administered to sheep. Ferrando and as- 

 sociates 959 also observed that the administration of cod-liver oil to lactating 

 cows results in a reduction of blood tocopherol, as well as in a decrease 

 of the fat in the milk. It is suggested that this phenomenon is not the re- 

 sult of an antagonistic action between the unsaturated iatty acids of cod- 

 liver oil and tocopherol, but rather that a critical ratio of tocopherol: un- 

 saturated fatty acids exists. In later studies, Brion, Ferrando, and col- 

 laborators 960 observed that cod-liver oil in normal doses did not affect the 

 plasma tocopherol level of the pig. 



(6) Maternal-Fetal Transfer of Tocopherols. Mason and Bryan 961 re- 

 ported, in 1938, that the placental transfer of vitamin E was negligible in 

 the rat, and that the mammary transfer was likewise decidedly limited. 

 In later studies by these workers, 962 it was shown that the maximum transfer 

 of vitamin E to newborn female rats attributable to supplementation of the 

 maternal diet during pregnancy and during lactation is insufficient to in- 

 sure fertility of these young on reaching maturity. Moreover, the store 



968 M. L. Quaife and P. L. Harris, Proc. Soc. Exptl. Biol. Med., 78, 188-191 (1951). 



969 R. Ferrando, P. Chenavier, and M. Cormier, Bull. soc. chim. biol., 31, 810-816 

 (1949). 



960 A. Brion, R. Ferrando, P. Chenavier, and J. Portal, Bull. soc. chim. biol., 38, 151- 

 154 (1951). 



961 K. E. Mason and W. L. Bryan, Biochem. J., 82, 1785-1791 (1938). 



962 K. E. Mason and W. L. Bryan, /. Nutrition, 20, 501-517 (1940). 



