A Study of the Reported Occurrence of Mesobilirubin in Human Bile. ∗

Abstract

Summary and conclusions

1. Paper and column chromatographic methods of separating bilirubin and mesobilirubin are described. 2. Use of these methods permits detection of mesobilirubin at the 0.5 mg % level in the presence of much larger amounts of bilirubin. 3. The spectroscopic distinction of biliverdin and mesobiliverdin (glaucobilin), and of their respective zinc complexes, is discussed. 4. Glaucobilin is readily formed from d- or i-urobilin, in addition to mesobilirubin: glaucobilin formation on FeCl₃ oxidation is thus not specific for mesobilirubin as suggested by others. 5. Mesobilirubin has not been detected in human bile but was definitely identified in a urine sample containing larger amounts of bilirubin. Its occurrence in the urine is believed to relate to an enterohepatic circulation.