ROLE OF BILE IN LIPID ABSORPTION 03 



ever, when stearic and oleic acids were mixed in a 1:1 ratio, 15% of the 

 mixture (7.5% of each acid) could be brought into solution in bile.'' 01 The 

 solubility could be doubled by adding an equivalent amount of sodium 

 carbonate. The solvent action of bile acids was found to be much less in 

 the case of the neutral fats. 605 



The unique ability of certain bile acids to form stable coordination com- 

 pounds must, in large part, be responsible for their solvent action which 

 allows them to transport the fatty acids into the mucosa cells. Cholic 

 acid possesses the property of crystallization. The solvent is retained most 

 tenaciously, and can be removed from the crystals only by prolonged heat- 

 ing under reduced pressure. This unusual property of cholic acid is magni- 

 fied many times in desoxycholic acid. 



(a) Discovery. The explanation for the behavior of cholic and desoxy- 

 cholic acid in bringing about a solution of fatty acids and other lipids is 

 largely based upon the brilliant research of Wieland and Sorge 506 on the 

 substance known as "choleic acid." This term had been coined in 1838 

 by Demargay 507 ; for several years it had been applied to a number of 

 acidic substances of biliary origin. However, in 1885, Latschinoff 508 

 applied this name to a nitrogen-free acid which occurred with cholic acid in 

 varying proportions, and which appeared to resemble the recently dis- 

 covered desoxycholic acid. 509 The designations "choleic" and "desoxy- 

 choleic" were used more or less synonymously by a number of workers 51 "' 51 ' 

 until the studies of Wieland and Sorge. 506 



The circumstances which led to the discovery of the nature of choleic 

 acid are of considerable interest. In investigating its composition, the 

 acid was subjected to dehydration by vacuum distillation by a method 

 analogous to that previously applied to desoxycholic acid. Instead of 

 obtaining a choladienic acid which was isomeric with that obtained from the 

 desoxycholic acid, it was found that the two unsaturated acids were identi- 

 cal. However, it was observed that a small amount of palmitic or stearic 

 acid was formed as well; it was proved that the aliphatic fatty acids did 



504 E. Pfliiger, Arch. ges. Physiol. (Pfliiger's), 88, 299-338 (1902). 

 606 \V. Marcet, Proc. Roy. Soc. London, 9, 306-308 (18.58); Arch. palh. A not. Physiol. 

 (Virchow's), 17, 204 (1859). 



506 H. Wieland and H. Sorge, Z. physiol. Chem., 97, 1-27 (1910). 



507 H. Demargay, Ann., 27, 270-291 (1838): Ann. chim. phys., [2], 67, 177-203 (1838); 

 Compt. rend., 6, 199-201 (1838). 



508 P. Latschinoff, Ber., 18, 3039-3047 (1885). 



509 F. Mylius, Ber., 19, 369-379; 2000-2009 (1886). 



510 V. Wahlgren, Z. physiol. Chem., S6, 556-567 (1902). 

 &11 A. Gullbring, Z. physiol. Chem., /,5, 448-458 (1905). 



