C. H. BEST 



Physiological Significance. It remains to be decided whether 

 a supplement of choHne is necessary in a diet which contains an ade- 

 quate amount of choHne precursor, methionine. A small part of the 

 lipotropic action of protein may be due to the tyrosine it contains. 

 The lipotropic action of inositol is inhibited in young animals by some 

 component of corn oil, perhaps the essential fatty acids. Work which 

 is in progress should determine the relative importance of these various 

 agents under physiological conditions. The addition of choline to the 

 diets of puppies given an alipotropic ration, prevents failure of liver 

 function and death in this species. Presumably, methionine would 

 have the same effect. Choline or methionine prevents the develop- 

 ment of haemorrhagic kidneys which may lead to the death of young 

 rats through failure of kidney function. The extension of this work 

 may throw some light on the etiology of developmental defects in 

 kidneys in man. 



Hepatic necrosis in rats is prevented by cystine and hepatic 

 cirrhosis by choline. Methionine, by providing a source of cystine or 

 of organic sulfur, prevents necrosis and, by enabling the body to make 

 choline from ethanolamine, prevents cirrhosis. 



Clinical Significance. The provision of diets high in protein 

 may exert a favorable effect on hepatic cirrhosis in man. It is reason- 

 able, in the light of the experimental evidence, to consider that this 

 effect may be due to the methionine contained in protein which acts 

 as a source of choline. A little evidence has been provided that choline 

 is effective in human hepatic cirrhosis. 



Evidence has been obtained that the high incidence of human 

 hepatic cirrhosis in certain districts of South Africa may be due to the 

 low "protein" content of the diet. This diet produces hepatic cirrhosis 

 in rats. We can no longer merely speak oi protein as a dietary con- 

 stituent without remembering that some of the amino acids, the 

 amounts of which vary in different proteins, have specific physiological 

 functions. At the moment, we are particularly interested in the 

 methionine contained in protein which, as stated above, provides a 

 source of choline. 



Various claims have been made for the beneficial effect of 

 choline in preventing liver injuries due to a variety of infectious 

 processes. Methionine is now being studied extensively by clinicians 

 in the hope that its well-established physiological action can be utilized 



