TRANSFORMATION OF BILIRUBIN TO UROBILIN 55'i 



Greenblatt and Greenhlatt {1051) foun<l sulfaguanidine to iiiliihit intes- 

 tinal urobilin formation, while Legge {KKIT) observed an increase of the rela- 

 tive concentration of mesobilane in rats which were fed sulfanilamide, i.e., 

 evidence for less complete reduction of bilirubin. The experiments of Watson 

 and co-workers {Jf)'.)S) who came to conclusions different from those of 

 Baumgartel are discu-ssed in the next subsection. 



9.1.3. Extraintestinal Formation of Urobilin. An extraintestinal for- 

 mation of urobilin has been claimed by many workers {lSJJtJ(iJ7,l'.t-U, 

 899-901 ,1017 ,2UGJJtl7 ,J<SSSJOAV> JorjJt) . The evidence was ba.sed on the 

 observation of urobilin in bile fistula animals or under conditions in which 

 no urobilin was found in intestine or urine or in which none would be exj)ected 

 — as, for example, after the ligature of the bile duct — or on the failure of 

 laxatives to decrease urobilinuria in some liver diseases, or on the observation 

 of urobilin in pleural and ascitic fluid in concentrations about ten times 

 higher than that in the blood — the bilirubin in the fluid decreasing on stand- 

 ing {2417). No evidence for formation of urobilin outside the intestine was 

 found, however, by McMaster and Elman {(>73,1S27) who ascribed the 

 positive results of others either to bilirubin having found its way into the 

 intestine and having been reabsorbed after intestinal transformation into 

 urobilin, or to infection of the bile passages by intestinal bacteria (rf. also 

 2377M19,29U). 



d-Urohilin. In infected bile duct and gall bladder infection, 

 urobilin formation has also been found by Elinan and AfcMaster 

 {073,67 Jt,lH29). Royer {2SH('); cf. also 19J2) u.sed the ratio of urobilin 

 to bilirubin in duodenal bile a.s evidence for infection of the gall 

 bladder in cholecystitis. Schwartz, Watson, and Sborov {2dl3,2.')15, 

 299S) found the urobilin formed from bilirubin by incubation in 

 infected bile or in the infected biliary tract of bile fistula iiatients to 

 be dextrarotatory, in contrast to the optically inactive mesobilene 

 and the strongly levorotatory tetrahydromesobilene ("stercobilin"). 

 The chemical nature of the compound has not yet been elucidated 

 (c/. Chapter IV, Section 6.4.). 



Watson and co-w^orkers suggest the following scheme: 



Biliruljin 



bacterial 



mesobilane 



l.ilo factor I I I |.'i'"- "I"' 



4, 4''cce> laclor 



"d-urohiiinogen" | /-tetrahydroiiiesobiiiine 



4' 4' ^ . 



"(/-urohilin" inesoltileiie /-tetraliydroiiu'sohileiie 



It is difficult to judge from the preliminary notes whether this .scheme is 



satisfactorily supported by the experimental evidence; we have not been 



