Abstract
The 6a hydroxylation of taurolithocholic acid was already proven in human liver microsomes; mass spectrometry, thin layer and gas chromatography were used to identify the reaction product, hyodesoxycholic acid. The present study aimed to prove that this reaction depends on cytochrome P 450. Microsomal fractions from human liver biopsies were submitted to carbon monoxide inhibition of the reaction and its reversibility with monochromatic light (450 nm). Increasing carbon monoxide concentrations (2 to 48%) in Warburg apparatus led to pronounced inhibitions of this reaction; Warburg's distribution constant K was 1.8 with 50% inhibition of hydroxylation. Highest reactivation of carbon monoxide inhibition was obtained with monochromatic light. This cytochrome P 450 dependent hydroxylation may be very important in the pathogenesis of intrahepatic cholestasis. Some drugs used clinically do cause intrahepatic cholestasis as they interfere with hydroxylation of hepatotoxic taurolithocholic acid. The causal or potentiating role of reduced hydroxylation in intrahepatic cholestasis remains an open question.
Translated title of the contribution | Cytochrome P 450 dependent 6a hydroxylation of taurolithocholic acid in man |
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Original language | German |
Pages (from-to) | 445-447 |
Number of pages | 3 |
Journal | Verhandlungen der Deutschen Gesellschaft für Innere Medizin |
Volume | No. 80 |
DOIs | |
State | Published - 1974 |
Externally published | Yes |