734 XI. VITAMINS E (TOCOPlIEHOLf^) 



away by attrition. Vitamin E therapy restores the pigmentation of the 

 teeth, not by forming more pigment, but ])y correcting the fmiction of the 

 enamel organ so that pigment can be properly deposited. 



Granados and co-workers^^^-^^ reported that, when manganese was in- 

 corporated in the salt mixture, depigmentation of the enamel of vitamin 

 E-deficient rats was inhibited. A possible explanation for this result 

 might be that the manganese acts upon the alkaline phosphatase in the 

 enamel organ of the depigmented incisors of rats on vitamin E-deficient 

 diets. However, Glavind et al.^^^ found that the alkaline phosphatase 

 activity in the enamel organ of the depigmented incisors of vitamin E- 

 deficient rats was not significantly different from that in the controls 

 which were fed vitamin E-rich diets. These results are difficult to corre- 

 late with those of Dam, Granados and Maltesen,^^'' Avho noted that man- 

 ganese was greatly increased in both the enamel and the dentine of ^'ita- 

 min E-deficient rats, as compared with that present in these tissues when 

 vitamin E was supplied. On the other hand, iron was found to be greatly 

 diminished in both the dentine and the enamel of the vitamin E-deficient 

 animals. Hamsters also exhibited depigmentation of the maxillary 

 incisors when subjected to a vitamin E-deficient diet.^^'^ 



m. The Role of Tocopherol as a Component of Various Enzyme Systems. 

 There are a number of reports on investigations of the action of tocopherol, 

 particularly as its phosphate ester, and of its effect on different enzyme 

 systems. D-a-Tocopheryl phosphate was employed in these tests, because 

 of its greater solubility in water as compared with the free vitamin, and 

 because of the implied behavior of the phosphate group. The phosphate 

 ester was found to inhibit practically every in vitro enzjmie system on which 

 it was tested. Houchin^^^ was the first to observe the inhibition of the 

 succinoxidase by a-tocopherol phosphate; this result has been confirmed 

 by a mmiber of investigators. ^'^^"''^ Jacol)i et al.^^^ reported that, when 

 calcium and aluminum were omitted from the medium, an extremely low 



»»< H. Granados, E. Aaes-J0rgensen, and H. Dam, Brit. J. Nutrition, 3, 320-334 (1949). 



^^ H. Granados, E. Aaes-J0rgensen, and H. Dam, Acta palhol. et microbiol. Scand., 27, 

 304-312(1950). 



^^ J. Glavind, E. Aaes-j0rgensen, H. Granados, and H. Dam, J. Dental Research, 29, 

 689(1950). 



3«' H. Dam, H. Granados, and L. Maltesen, Ada Physiol. Scand., 21, 124-130 (1950). 



^ W. M. Govier, V. Bergmann, and K. H. Beyer, /. Pharmacol. Exptl. Therap., 85, 

 143-149(1945). 



^^ H. P. Jacobi, S. Rosenblatt, J. W. Chappell, and S. Morgulis, Arch. Biochem., 27, 

 9-18(1950). 



390 p. D. Boyer, M. Rabinovitz, and E. Liebe, Ann. New York Acad. Sci., 62, 188-194 

 (1949). 



3" S. R. Ames, J. Biol. Chem., 169, 503-512 (1947). 



J 

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