ROLE OF BILE IN LIPID ABSORPTION 75 



in positions 3 and 12 was established as a. 436 Pythoeholic acid could be 

 converted to ordinary desoxycholic acid (3a,12a-dihydroxycholanic acid). 

 It was suggested that the presence of pythoeholic acid in the bile of the 

 Boidae may be the result of a genetic mutation in snakes producing cholic 

 acid, or that the Boidae may have retained the ability to produce it from 

 the limbed reptiles. The only other lactone-forming bile acid has been 

 isolated from the chelonian reptiles, Amyda japonica (fresh- water alli- 

 gator turtle) and Emys orbicularis (European pond-tortoise). 435 



Although the bile acids most frequently encountered are all members of 

 the C 2 4 series, several examples of bile acids have been found which contain 

 26 to 30 carbons. It is possible that these acids, containing more than 24 

 carbon atoms, represent intermediates between the parent sterol and the 

 C 2 4-bile acids. Thus, Tukamoto and Kataoka 437 suggested that the tetra- 

 hydroxynorsterocholanic acid found in the bile of several fishes is to be 

 regarded as an intermediate between 7-dehydrocholesterol and the C 2 4-bile 

 acids. Wieland and Kishi 417 isolated an acid from cattle bile having the 

 empirical formula, C28H46O4. Because of its possible relation to the sterols, 

 it Avas given the name, slerocholic acid. 



Several interesting acids have been obtained from the bile of the toad. 

 The first of these is trihydroxybufosterocholenic acid (Formula VI), 

 which was first isolated by Shimizu and Oda. 438 It has the empirical for- 

 mula, C28H46O5, and appears to be closely related to sterocholic acid. On 

 the basis of its degradation on ozonization to bisnorcholic acid, Shimizu 

 and Kazuno 439 proved that the hydroxyl groups are on carbons 3, 7, and 12. 

 The second acid isolated from toad bile is trihydroxyisobufosterocholenic 

 acid. 440 This acid is isomeric with trihydroxybufosterocholenic acid; 

 the isomerism has been ascribed to the position of the carboxyl group, 

 which is believed to be on the next to the last or second from the last carbon 



OH ('II, CH 3 



CH 3 



H 3 C 



,C\h 



Ha 



Ys/ /r- / \ch 3 



N 'OOH 

 CH 3 COOH 



HO H OH 



(VI) Postulated Structure of Trihydroxybufosterocholenic Acid 



437 M. Tukamoto and Y. Kataoka, J. Biochem. (Japan), 32, 473-475 (1940). 

 » 8 T. Shimizu and T. Oda, Z. physiol. Chem., 227, 74-83 (1934). 



439 T. Shimizu and T. Kazuno, Z. physiol. Chem., 2U, 167-172 (1936). 



440 T. Shimizu, T. Oda, and T. Kazuno )# Z. physiol. Chem., 239, 67-75 (1936). 



