X. J]FFECTS OF DEFICIENCY 63 



l)y its addition to an i)i vitro system followed by the isolation of methyl- 

 containing products and estimation of the isotopic carbon and hydrogen. 

 More general procedures include measurements of effectiveness in the 

 pre^'ention of fatty livers and of renal lesions in rats, of growth of rats on 

 homocystine-containing, methionine-poor diets, of stimulation of growth 

 and prevention of perosis in chicks or turkey poults, and of extent of con- 

 version of homocysteine and of guanidoacetic acid to methionine and 

 creatine, respectively, in in vitro tissue systems. Choline, with at least one 

 labile methyl group after oxidation to betaine and with one or more carl)ons 

 that may participate in formate-to-methyl synthesis under the proper 

 conditions, reacts positi^'ely in each of these procedures. It is particularly 

 effective in reactions in which it ser\'es directly, presumably as a constitu- 

 ent of phospholipids or of acetylcholine, rather than as a source of methyl. 

 This appears to be the case in so far as its lipotropic activity is concerned 

 and, possibly, its antihemorrhagic and antiperotic activities also. Obvi- 

 ously, it is not always possible to distinguish with certainty between evi- 

 dences of a deficiency of methyl and of choline in experiments on animals. 

 It is important, nevertheless, that deficiency symptoms, prex'ented by 

 choline, may be produced without difficulty in se\'eral animal species. 



B. RAT 



WENDELL H. GRIFFITH and JOSEPH F. NYC 

 1. Renal Lesion 



The rat has been the principal test animal in investigations of choline. 

 The recognition of the lipotropic action of choline in adult rats by Best 

 has been described earlier (Section IV C 2). The importance of this sub- 

 stance in the rmtrition of the young rat was demonstrated by ( Iriffith (t al., 

 who showed that choline was essential in weanling rats not only for the 

 prevention of the fatty liver but also for the maintenance of tissue structure 

 and even for survival. ^"^ 



The feeding of low choline diets to male rats, 20 to 26 daiys of age, results 

 in a spectacular series of effects which reach a crisis within 6 to 8 days. 

 This critical period may terminate fatally, or it may be followed by a 

 rapid, partial recovery. Recovery on the same diet that produces severe 

 degenei'ation of tissues is highly interesting and as yet an unexplained 

 phenomenon. A marked increase in liver fat occurs within 48 hours and is 

 maximal after 4 to (i days. Renal lesions, named hemorrhagic degeneration, 

 develop between the sixth and eighth days; the animals become noticeably 



1 W. H. Griffith and N. J. Wade, Froc. Sue. Exptl. Biol. .Med. 41, ISS (1939). 



2 W. H. Griffith and N. J. Wade, J. Biol. Chem. 131, 567 (1939). 



3 W. H. Griffith, ./. Xutrition 19, 437 (1940). 



^ W. H. Griffith, Biol. Sijmpo.Hia 5, 193 (1941). 



