70 II. DIGESTION AND ABSORPTION OF FATS 



atom, respectively, on the side chain, instead of occupying the terminal 

 position. 4 " 



Toad bile acids contain several polyhydroxy derivatives having ;i steroid 

 nucleus which should be included in this category, although they are not 

 strictly bile acids. One of these (formula Yii) is called pentahydroxy- 

 bufostane (C28H50O5), and it appears to be 3,7, 12,24, 25-pentahydroxy- 

 ergostane. 442 It occurs in toad bile as the sulfuric acid ester. The second 

 representative of this group is tetrahydroxynorbufostane (formula VIII), 443 

 (C27H48O4). Since both of these compounds have been isolated from the 

 winter bile of the hibernating Japanese toad (Bufo vulyaris japonica) , it is 

 possible that they are products resulting from the depressed metabolism 

 which would not appear in the bile of a toad under normal metabolic 

 conditions. 



OH CH 3 



CH 3 1 OH CH 3 



" A 1 ch 3 | 



aa 



*sWJ 



HOi 



V 



H3C 



HO^CH 3 /\l/\ 



V 0H HOC— CH, R J 



IK) Vx/ OH 

 CH 3 H 3 C CHoOH 



(VII) Pentahydroxybufostane (?) (VIII) Tetrahydroxynorbufostane (?) 



Several other related compounds which have been found in toad bile 

 include two tetrahydroxycholestanes (or tetrahydroxycholanes), one of 

 which gives 3,7,12-triketo-20,22-epoxycholane on oxidation with chromic 

 acid, while the second one, which occurs as the sulfuric acid ester, is de- 

 hydrated during hydrolysis to trihydroxycholene. 429 



The bile acids of the frog have been shown to resemble those of the toad. 

 Haslewood 444 ' 445 reported that the chief bile acid of the European brown 

 frog, Rana temporaria, is apparently a sulfate ester of an alcohol which 

 they call "ranol," and which has the empirical formula, C27-2sH 4 3-45(OH) 6 . 

 The molecule is believed to contain a primary alcohol group and secondary 

 hydroxyls on carbons 3, 7, and 12. Trihydroxybisnorsterocholanic acid, 

 C26H44O5, has also been reported by Kurauti and Kazuno 446 in the bile of 



441 T. Shimizu and T. Kazuno, /. Biochem. (Japan), 25, 245-247 (1937). 



442 T. Kazuno, Z. physiol. Chem., 266, 11-30 (1940). 



443 H. Makino, Z. physiol. Chem., 220, 49-54 (1933). 



444 G. A. D. Haslewood, Biochem. J., 50, xxxv (1952). 



445 G. A. D. Haslewood, Biochem. J., 51, 139-143 (1952). 



446 Y. Kurauti and T. Kazuno, Z. physiol. (fyem., 262, 53-60 (1930). 



