VITAMINS 



217 



by failure to recover even when the animal is fed large amounts of the 

 vitamin. The females, on the other hand, continue to ovulate normally, 

 mating occurs, and the foetuses grow until about the twelfth or thirteenth 

 day of gestation, at which time they die and are resorbed by the mother's 

 body. Injury to the female is less severe than to the male, for normal 

 young may be born in the next gestation period if an abundance of 

 vitamin E is supplied. However, repeated resorptions may lead to 

 paralysis and other serious injury. Similar experiments with mice indi- 

 cate that females respond to vitamin E deficiencies as do rats, but the 

 males do not show testicular damage after prolonged lack of the vitamin. 



Deficiency of vitamin E produces muscle dystrophy in several species. 

 This is a condition of impaired nutrition of the cell that results in 

 degenerative changes in the muscle fibers. Eventually the fibers atrophy 

 and are replaced by connective tissue and fat. Such changes necessarily 

 result in paralysis, although the two do not always correspond in degree. 

 The chemical composition of the involved muscles is altered in that lipide 

 phosphorus and cholesterol increase greatly, whereas there is a marked 

 decrease in glycogen and creatine. Abnormally large amounts of creatine 

 are excreted in the urine. Muscle dystrophy has been observed in dogs, 

 rabbits, guinea pigs, and rats, and cures have been effected through ad- 

 ministration of vitamin E. Muscle dystrophy is also a disease of man, 

 but unfortunately human patients are not cured by vitamin E. The 

 vitamin E content of eggs coincides closely with their hatchability and 

 with the vitality of the young chicks. Because of the function of hor- 

 mones in reproduction, it has been suspected that a relationship exists 

 between tissue concerned with their production, for instance, the pituitary 

 gland, and vitamin E supply. Experimental data to support such a 

 view, however, are still lacking. Ability to store vitamin E is pronounced. 



Evidence is accumulating which indicates that the chief physiological 

 function of vitamin E may be associated with its pronounced antioxidant 

 properties. The muscles of vitamin E deficient animals show a greatly 

 increased respiration (oxygen uptake) as compared with normal muscles, 

 and the respiration is dramatically reduced by administration of vitamin 

 E to such animals. It has recently been found, also, that feeding ade- 

 quate amounts of vitamin E greatly reduces the oxidation of carotene 

 and vitamin A in the intestinal tracts and body tissues of animals so 

 that they are able to remain in good condition on much less vitamin A 

 than would otherwise be required. 



Chemical nature 



Vitamin E activity in foodstuffs has been traced to four phenols 

 (hydroxy derivatives of benzene), which are known as alpha-, beta-, 

 gamma-, and delta-tocopherol, respectively. The alpha form has much 



