NUTRITIONAL FACTORS OF DOUBTFUL STATUS 709 



C2H5 

 5 — N— CH 2 — CH 2 — OH 



ci- 



C 2 H 6 



triethylcholine chloride 



the action of acetylcholine is unaffected. These data indicate that the 

 choline analogue may interfere with the synthesis of acetylcholine from 

 choline. 



L-Penicillamine (/3,,5-Dimethylcysteine). Wilson and du Vigneaud 51 

 found that the growth of young albino rats was inhibited when L-penicil- 



CH 3 NH 2 

 HS C CH COOH 



CH 3 



L-penicillamine 



lamine hydrochloride hydrate was added to the diet, and that normal 

 growth was restored by feeding choline chloride. However, this inhibitor 

 appears not to be competitive with choline, for aminoethanol was found 

 to be even more effective than choline in overcoming the growth inhibi- 

 tion. Dimethylaminoethanol and monomethylaminoethanol were also 

 effective in restoring the normal rate of growth, but methionine, cysteine, 

 cystine, homocysteine and homocystine were without activity. These in- 

 vestigators suggested that "penicillamine may exert its toxic action by 

 blocking either the synthesis or the utilization of aminoethanol." 



Coramine (N,N-Diethylnicotinamide). A type of inhibition involving 

 choline was observed by Wilson and Leduc. 52 Weanling mice were fed on 

 a low protein, choline-deficient diet to which coramine was added in 

 varying amounts. The compound at a concentration of 0.25 per cent per- 



-C— N(C 2 H 6 ) 2 



coramine 



mitted very slight growth; 0.5 per cent allowed maintenance without 

 growth; and 1.0 per cent caused a loss in weight. The inhibitory effects of 

 coramine are reversed by the addition of choline to the diet. Even though 

 coramine is structurally unrelated to choline, its detoxication apparently 

 takes place by transmethylation and its presence in the diet increases 

 the requirement for a methyl donor. Choline must function here only as 



