TOCOPHEROLS IX VARIOUS METABOLIC PROCESSES 737 



from a vitamin E-free diet are associated with a lack of this vitamin in the 

 adipose tissue or in other fat-storing organs so pronounced that there is an 

 insufficient content of antioxidants to pre^'ent the development of peroxides 

 in the tissues. This latter condition occurs especially if there are unusually 

 large amounts of highly unsaturated fats in the diet. 



a. The in vivo Action of Vitamin E as an Antioxidant. Barnes, Lundberg, 

 Hanson, and Burr^- Avere the first to note that, although the fats of rats fed 

 for 100 days on a vitamin E-free diet were extremely susceptible to ran- 

 cidity, the administration of a single dose of a-tocopherol in the diet 

 restored the stability of the body fats to their normal level. The maxi- 

 mum deposition of the tocopherol took place in &Q\e\\ to ten daj^s, after 

 which the quantities in the fat gradually' decreased to one-half of the 

 ma.ximum value during the course of two months. ^^ a-Tocopherol was 

 found to be slightl}^ more effective in the subsequent protection of the 

 body fats than was 7-tocopherol ; this effect is exactly opposite to that 

 obtained when the tocopherols are added directl}'' to the fats in vitro. 0- 

 Tocopherol was found to ha\'e a potency intermediate between that of the 

 a- and the 7-types. Since the quantities of a-, /?-, and 7-tocopherol 

 present in the fats varied directly with their ability to stabilize fat, varia- 

 tions in the extent of absorption are belie\'ed to be a partial explanation 

 for the different antioxygenic action of the three types of tocopherols when 

 fed to the animals. Further studies on the in vivo effect of tocopherols on 

 fat stability have been recorded by the Burr-Lmidberg group. ^^'^^-^^^ 



In addition to rats, other animals use tocopherol to stabilize their body 

 fats against peroxidation. Thus, Major and Watts*^^ recorded a similar 

 protective effect in the case of rabbits on a purified diet and fed or injected 

 with tocopherols at relatively high levels. Carpenter and Lmidberg^^^ 

 were able to obtain increased protection of the fat of baby pigs when the 

 tocopherol supplements were continued o\-er a period of twelve weeks 

 before the animals were killed. The storage of turkeys was improved, 

 and the peroxide values of the fat were lower, when increased amounts of 

 tocopherol were fed prior to the killing. ^^ 



The effect of tocopherol feeding upon the stability of milk is still some- 

 what open to question, due to the conflicting reports of different workers. 

 Burr, Lundberg, and Chipault"" obser\-ed that, when a vitamin E-free 

 diet was fed to cows, the effect upon the stabihty of the butterfat was 



*'o G. O. BvuT, \V. O. Lundberg, and J. 11. Chipault, Oil & Soap, 23, 382-384 (1946). 

 ^" R. Major and B. M. Watts, J. Nutrition, 35, 103-116 (1948). 

 ■"2L. E. Carpenter and W. O. Lundberg, Ann. New York Acad. Sci., 52, 269-275 

 (1949). 



