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Ethanol-Inducible Liver Cytochrome P-450 in the Rat: Relative Specificity for Ethanol Oxidation Activity in Vitro

  • A. M. Mungikar
  • C. Hetu
  • J.-G. Joly

Abstract

Ethanol induces in rat liver microsomes a form of cytochrome P-450 differing in substrate specificity from cytochrome P-450 species present in controls or in rats treated with phenobarbital or 3-methylcholanthrene. Its relative capacity to oxidize ethanol remained to be determined and was studied using highly purfied cytochrome P-450 preparations and comparing their activity in a reconstituted microsomal ethanol oxidizing system (MEOS). On a molar basis, reconstituted MEOS activity was found to be highest when assayed with ethanol-inducible cytochrome P-450, intermediate with cytochrome P-450 from phenobarbital-treated rats, and lowest with cytochrome P-450 from controls or 3-methylcholanthrene-treated rats. A decrease in apparent Km for ethanol was also found to be associated with higher MEOS activity of ethanol-inducible cytochrome P-450. The induction by ethanol of a catalytically distinct from of cytochrome P-450, and the comparatively high ethanol oxidizing activity of this cytochrome P-450 species, are in accordance with the MEOS hypothesis.

Keywords

Chronic Ethanol Ethanol Oxidation Molar Activity Microsomal Ethanol Oxidize System Biospecific Affinity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1980

Authors and Affiliations

  • A. M. Mungikar
    • 1
  • C. Hetu
    • 1
  • J.-G. Joly
    • 1
  1. 1.Clinical Research Center and Department of MedicineHopital Saint-Luc and Universite de MontrealQuebecCanada

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