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An alternate pathway for bilirubin catabolism
Author(s) -
Kaul Ravi,
Kaul Hari K.,
Krishna Murti C.R.
Publication year - 1980
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(80)80802-7
Subject(s) - citation , medicine , library science , history , computer science
Parturition associated hyperbaric oxygen toxicity is manifest in newborn humans as increased heme catabolism leading to hyperbilirubinaemia. Functionally mature hepatocytes are not available to deal with the extra load of bilirubin and physiological jaundice ensues with increased levels of circulatory unco]lJugated bilirubin. The mature hepatocyte in contrast is equipped with UDP-glucuronyl transferase and can render the bile pigment hydrophilic by conjugation with glucuronic acid [ 11. Pathways for bilirubin degradation involving photooxygenation are mediated by singlet oxygen 121. The first-order rate constant for bilirubin degradation in an in vitro system can be stimulated by an order of 10 by incorporation of a superoxide generating system such as xanthine-xanthine oxidase. The stimulation caused by superoxide is neutralized by the inclusion of superoxide dismutase in the assay mixture [3,4]. Does the superoxide radical function as a mediator of bilirubin degradation in vivo? Here we show that superoxide-mediated bilirubin degradation is an alternate catabolic pathway for bilirubin metabolism.