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Gastroenterology. 1993 Jan;104(1):203-16.

Cytochromes P-450 in human hepatocyte plasma membrane: recognition by several autoantibodies.

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Institut National de la Santé et de la Recherche Médicale: Unit 24, Clichy, France.



Anti-cytochrome P-450 autoantibodies are present in several forms of autoimmune hepatitis. The possibility that cytochromes P-450 are present in the plasma membrane of human hepatocytes was examined.


(1) Plasma membranes with microsomal contamination < 1%, as judged from the activities of glucose-6-phosphatase and NADH-cytochrome c reductase, were prepared. (2) After exposure of uncut, fixed hepatocytes to antibodies, immunofluorescence and immunoperoxidase studies were performed.


(1) The specific content of cytochrome P-450 in plasma membrane was 9% of that in microsomes. Plasma membranes showed NADPH-cytochrome c reductase and mono-oxygenase activities; immunoblots showed the presence of cytochromes P-450 1A2, 2C, 2D6, 2E1, and 3A4; cytochromes P-450 1A2, 2D6, and 2C were also recognized by anti-liver microsome and anti-liver/kidney microsome type 1 and type 2 autoantibodies, respectively. (2) Immunofluorescence and immunoperoxidase labeling of the plasma membrane was observed with the three auto-antibodies and with anti-cytochrome P-450 1A2, 2C, 2E1, or 3A4.


It is concluded that cytochromes P-450 are present and functional in the plasma membrane of human hepatocytes and that anti-cytochrome P-450 autoantibodies recognize epitopes expressed on the outer surface.

[Indexed for MEDLINE]

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