Multiplicity and functional diversity of rat hepatic microsomal cytochrome P450 isozymes

  • W. Levin
  • P. E. Thomas
  • L. M. Reik
  • A. W. Wood
  • D. E. Ryan


Three potential fates await lipophilic foreign chemicals that enter a living organism: the compounds remain unchanged, undergo spontaneous breakdown, or enzymatic metabolism. The biotransformation products are, in general, more water soluble and are more easily eliminated from the organism than the parent compounds. Hence, both the duration and intensity of action of many biologically active xenobiotics, including drugs, are determined largely by their rate of conversion to more polar products. Although the biotransformation of xenobiotics occurs in many tissues and organs of higher animals, the highest metabolic activity resides in the liver. The foundations for modern research in xenobiotic metabolism were established through the pioneering efforts of several investigators (Mueller & Miller, 1953; Axelrod, 1955; Brodie et al., 1955; Williams, 1959) during the 1950s.


Liver Microsome Microsomal Cytochrome Cytochrome P450C Cytochrome P450 Isozyme Steroid Sulfate 
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Copyright information

© Macmillan Publishers Limited 1984

Authors and Affiliations

  • W. Levin
    • 1
  • P. E. Thomas
    • 1
  • L. M. Reik
    • 1
  • A. W. Wood
    • 1
  • D. E. Ryan
    • 1
  1. 1.Department of Experimental Carcinogenesis and MetabolismHoffmann-La Roche Inc.NutleyUSA

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