SYNTHESIS AND DETERMINATION OF THE LIPOTROPIC ACTIVITY OF THE BETAINE HYDROCHLORIDES OF dl-SERINE, GTHREONINE, AND dl-ALLOTHREONINE*

This paper reports the synthesis of the betaine hydrochlorides of serine, threonine, and allothreonine and a study of the action of these substances on the lipid content of the livers of rats fed a high fat, low protein diet. This work was undertaken for two purposes. Best and Huntsman (1) found that choline prevented the development of fatty livers in rats fed a high fat diet and that betaine possessed a similar lipotropic effect,. Since choline contains a hydroxyl group, it was of interest to determine the lipotropic activity of some hydroxybetaines which are closely related to choline in structure. It also seemed possible that these studies might throw some light on the origin of choline in the animal body. The discovery of Channon and Wilkinson (2) and of Best and Huntsman (3) that casein has a lipotropic effect has been interpreted as indicating the possible synthesis of choline from one of the constituent amino acids of casein. Of the amino acids of casein, serine, containing the hydroxyethylamine grouping, is most closely related structurally to choline. Hence the physiological behavior of serinc betaine is of particular interest, although it represents only one of