TOCOPHEROLS IN VARIOUS METABOLIC PROCESSES 733 



voiced the opinion that the factor important for the prevention of the 

 lesions "may be either an amino acid labile to commonly employed methods 

 of purifying easehi, or an unkno^^^l factor associated with crude casein." 



Some data indicate that \'itamin E may be at least one essential factor in 

 preventing ulcer formation. Jensen""* reported that the administration of 

 a-tocopherol decreased the incidence of ulcer formation in rats previously 

 deficient in vitamin A, and therefore predisposed to ulcer. Harris and co- 

 workers'^^ proved that the beneficial action of a-tocopherol was not due 

 to its sparing action on vitamin A (thus making more of the latter available 

 to the tissues) ; even with high intakes of \'itamin A, tocopherol was still 

 necessary to improve the ulcer condition. In a later study by Hove and 

 Harris,"^ indisputable evidence was presented that a-tocopherol increased 

 the rate of cure of stomach lesions produced in rats by total starvation for 

 eight days when repletion was carried on with 40 Calories daily of a vitamin 

 E-free diet. a-Tocopherol had beneficial effects upon the incidence and 

 severity of rumen lesions produced by semistarvation (20 Calories daily 

 for forty days) when lard was in the diet, but it did not improve the condi- 

 tion when the ulcers were produced by hydrogenated coconut oil. The 

 latter results only partially confirm an earlier report of Miller et al.^'^' 

 It is suggested that both a-tocopherol and the essential fatty acids (which 

 are absent from hydrogenated coconut oil) are necessary to produce the 

 beneficial action. 



1. The Role of Vitamin E in Depigmentation of the Teeth. Moore*~^"^ 

 and Davies and Aloore^^" pointed out the relationship of vitamin E de- 

 ficiency to depigmentation of the maxillary incisors of the rat. When the 

 dietary protein was an additional hmiting factor, the pigmentation of the 

 mandibular incisors was also less than normal. The depigmentation re- 

 sulted as a secondary effect of atrophic changes in the enamel organs. '^^~'*' 



Under ordinary conditions, the pigment is being continuously formed 

 and deposited in the ena.mel organ of the incisor, to replace that worn 



"U. L. Jensen, Science, 103, 586-587 (1946). 



'" P. L. Harris, E. L. Hove, M. Mellott, and K. Hickman, Proc. Soc. Expll. Biol. Med., 

 64,273-277(1947). 



"6 E. L. Hove and P. L. Harris, /. Nutritimt, 40, 177-191 (1950). 



'"J. A. Miller, B. E. Kline, H. P. Riisch, and C. A. Baumann, Cancer Research, 4, 

 153-158, 756-761 (1944). 



3'8T. Moore, Biochem. ./., 37, 112-115 (1943). 



'"T. Moore, Ann. New York Acad. Sci., 52, 206-216 (1949). 



^ A. W. Davies and T. Moore, Nature, 147, 794-796 (1941 ). 



3«i J. T. Irving, Nature, 150, 122-123 (1942). 



382 H. Granados, K. E. Mason, and H. Dam, ./. Dental Research, 24, 197 (1945). 



38' H. Granados, K. E. Mason, and H. Dam, J. Dental Research, 25, 179 (1946). 



