676 VI. OCCURRENCE OF LIPIDS IN THE ANIMAL 



lipids, and Woolley 819 prepared an inositol-containing phospholipid from 

 soybean oil which contained as much as 16% of inositol. The great im- 

 portance of this compound in the animal body has been recognized only 

 since the discovery by Folch 820 alone and with Woolley 821 that the inositol 

 phosphatides belong in one of the three classes of components which make 

 up the lipids formerly referred to as cephalins. Since this inositol phos- 

 pholipid comprises an important part of such an essential organ as the 

 brain, it is not unexpected to find it classified as an essential dietary com- 

 ponent. 



Gavin and McHenry 802 were the first to indicate that inositol has a lipo- 

 tropic action in rats. When this substance was added to the diet of rats 

 with fatty livers induced by the administration of biotin in conjunction with 

 thiamine, riboflavin, pantothenic acid, and pyridoxine, the increase of fatty 

 acids and of cholesterol was prevented. Thus, this lipotropic action re- 

 sembles that of lipocaic, although the authors do not state that the active 

 agent in lipocaic is necessarily inositol. Engel 822 obtained a lipotropic ac- 

 tion by as small an amount as 3 mg. of inositol, in the case of livers refrac- 

 tory to choline. However, he did not carry out tests with biotin fatty 

 livers. In a later study by Gavin et al., 823 it was found that, whereas cho- 

 line is effective in reducing the fat in the case of thiamine fatty livers, and is 

 partially effective against cholesterol fatty livers, it is almost completely 

 inactive toward biotin fatty livers. On the other hand, inositol and lipo- 

 caic are both lipotropic toward the biotin fatty liver. Lipocaic differs from 

 inositol in the fact that it is ineffective against fatty livers produced by feed- 

 ing cholesterol with a high-fat diet. Inositol is entirely inactive as a lipo- 

 tropic agent in the case of the thiamine fatty liver. The addition of other 

 B vitamins is thus required before inositol exhibits its lipotropic action. 



Beveridge 824 reported that the feeding of corn oil actually obliterated the 

 lipotropic action of inositol. This result was confirmed by Beveridge and 

 Lucas. 825 Engel 822 had previously noted that some augmentation of the 

 action of inositol could be produced by feeding corn oil. On the other hand, 

 Blewett and associates 826 noted that the injection of inositol together with 



819 D..W. Woolley, J. Biol. Chem., 147, 581-591 (1943). 



820 J. Folch, J. Biol. Chem.., 146, 35-44 (1942). 



821 J. Folch and D. W. Woolley, J. Biol. Chem., 142, 963-964 (1942). 



822 R. W. Engel, J". Nutrition, 24, 175-185 (1942). 



823 G. Gavin, J. M. Patterson, and E. W. McHenry, J. Biol. Chem., 148, 275-279 

 (1943). 



824 J. M. R. Beveridge, Science, 99, 539-540 (1944). 



825 J. M. R. Beveridge and C. C. Lucas, J. Biol. Chem., 157, 311-321 (1945). 



826 M. Blewett, I. G. Campbell, and J. Olley, Nature, 164, 621-622(1949). 



