LIPID STORAGE UNDER ABNORMAL CONDITIONS 665 



The lipotropic action of choline is associated with the intact molecule rather 

 than with its methyl groups. In the absence of this essential building 

 stone, phospholipids such as the lecithins cannot be formed. Neutral fats 

 then accumulate in the liver as a result of inadequate means for transport- 

 ing them to the fat depots. 



(&') The Effect of Choline and Related Compounds on Growth: Al- 

 though choline exerts no pronounced effect on growth under ordinary con- 

 ditions, a definite correlation between increased growth and choline intake 

 can be demonstrated in animals receiving diets deficient in labile methyl 

 groups. In fact, the original discovery of du Vigneaud et al. e56 that homo- 

 cystine can support the growth of the rat in the absence of methionine when 

 choline is present is a demonstration of the growth-promoting action of 

 choline. However, this effect is obviously an indirect one which results 

 from the synthesis of an essential amino acid through the mediation of the 

 methyl groups of choline. Chandler and du Vigneaud 739 have shown that 

 the choline analogue, betaine, is likewise able to support the growth of rats 

 receiving homocystine diets, although it is not as effective as choline itself. 

 On the other hand, ethionine has a toxic effect on the growth of rats, 649,740 as 

 does also the ethyl analogue of choline, namely triethylcholine. 741,742 The 

 failure of weanling rats receiving triethylcholine to grow ma}^ possibly ex- 

 plain the apparent lipotropic action of this compound. 



Although du Vigneaud reported that dimethylaminoethanol, (CH 3 ) 2 - 

 NCH 2 CH 2 OH, could not substitute for choline in effecting growth when 

 homocystine was fed, Jukes and Oleson 743 found that this compound ex- 

 hibited a choline-like effect in promoting growth and in preventing perosis 

 in the chick, on a diet deficient in choline. Moreover, deuterium-containing 

 methyl groups appeared in choline from rats fed deuteriodimethylamino- 

 ethanol which had the isotope in the methyl group. 652 



(c') The Effect of Choline on the Kidney: Griffith and Wade 744 were the 

 first to present evidence of the important effect of choline in preventing 

 hemorrhagic degeneration of the kidneys. Young rats, placed on a cho- 

 line-low diet, developed this deficiency within ten days; in addition to the 

 renal enlargement and the fatty livers, hypertrophy of the spleen and a re- 

 gression of the thymus were likewise noted. Only 2 mg. of choline per day 



739 J. P. Chandler and V. du Vigneaud, J. Biol. Chem., 185, 223-229 (1940). 



740 H. M. Dyer, J. Biol Chem., 124, 519-524 (1938). 



741 J. A. Stekol and K. Weiss, J. Biol. Chem., 185, 585-587 (1950). 



742 C. S. McArthur and C. C. Lucas, Biochem. J., 46, 226-231 (1950). 



743 T. H. Jukes and J. J. Oleson, /. Biol. Chem., 157, 419-420 (1945). 



744 W. H. Griffith and N. J. Wade, Proc. Soc. Exptl. Biol. Med., 41, 188-190, 333-334 

 (1939). 



