C H A PTER XII 



CHOLINE 



I. INTRODUCTION 



Choline has been known since 1862, when it was discovered by 

 A. Strecker ^ in bile. Its inclusion in the vitamin B complex requires 

 even more justification than the inclusion of inositol, for it differs 

 markedly from the other members of the complex. 



In 1924, N. F. Fisher ^ and Allan et al.^ independently discovered 

 that depancreatised dogs maintained on insulin developed large fatty 

 livers, the formation of which was prevented by feeding fresh beef 

 pancreas ; a few yeai;s later, J. M. Hershey * found that egg yolk 

 lecithin also prevented fatty liver formation. In 1932, C. H. Best 

 and M. E. Huntsman ^ showed that the accumulation of fatty acids 

 in the livers of rats maintained on a diet containing 40 % of beef fat 

 was prevented by the inclusion of choline or betaine in the diet and, 

 in the following year, C. H. Best and J. H. Ridout ^ showed that 

 choline or betaine likewise prevented the deposition of fat in the liver 

 resulting from the feeding of cholesterol. Best et al.'^ concluded that, 

 since fatty liver formation caused by feeding fat was due to an increase 

 in the neutral fat fraction and that caused by cholesterol was due to 

 the formation of cholesteryl esters, choline and betaine were concerned 

 with the metabolism of both fat and cholesterol. Choline was also 

 found to prevent the formation of fatty livers due to the feeding of 

 sucrose. 8 Thus, choline accelerated the removal of fat from rat's 

 liver under a variety of dietetic conditions, whilst the amount of 

 choline in the diet was an important factor in determining the level 

 of fat in the liver. 



Thus, superficially at all events, choline appeared to possess the 

 essential characteristics of a vitamin in being necessary for the well- 

 being of an experimental animal and having to be supplied pre-formed 

 in the diet. In its absence, characteristic deficiency symptoms appeared 

 and these were cured by administration of choline. 



The suggestion that choline should be regarded as a member of the 

 vitamin B complex was made independently by B. Sure ® and 

 P. Gyorgy and H. Goldblatt ^^ in 1940. The former showed that it 



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