2 CHOLINE 



1. Stainable Fat 108 



2. Ceroid 113 



3. Portal versus Non-Portal Cirrhosis 114 



XI. Pharmacology 123 



XII. Requirements 128 



A. Requirements of Animals 128 



B. Requirements of Human Beings 129 



I. Nomenclature and Formula 



ROBERT S. HARRIS 



Accepted name: Choline 



Obsolete name: Bilineurine 



Empirical formula: C5H1BO2N 



Chemical name: /3-Hydroxyethyltrimethylammonium hydroxide 



Structure : 



(CH3)3N— CH2— CH2OH 



I 

 OH 



II. Chemistry 



WENDELL H. GRIFFITH and JOSEPH F. NYC 



A. ISOLATION 



Choline is widely distributed in biological materials as free choline, as 

 acetylcholine, and as more complex phospholipids and their metabolic in- 

 termediates. It is an integral part of the lecithins, which accounts for its 

 occurrence, in combination at least, in all plant and animal cells. It is also 

 one of the bases of the sphingomyelins of animal tissues. Phosphorylcholine, 

 glycerylphosphorylcholine, and the ester of phosphorylcholine with sphingo- 

 sine have been reported to occur, but it is uncertain to what extent these 

 components of phospholipids normally exist free in tissues. Choline is char- 

 acterized by a trimethyl quaternary nitrogen. Substances related to choline 

 in this respect, include glycine betaine, carnitine, and ergothionine. From 

 the viewpoint of lability of methyl groups, related compounds are methio- 

 nine, dimethyl -/3-propiothetin, and dimethylthetin. The latter is of con- 

 siderable importance in laboratory studies but is not known to occur 

 naturally. 



