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Cytokine‐mediated production of nitric oxide in isolated rat hepatocytes is dependent on cytochrome P‐450III activity
Author(s) -
Kuo Paul C.,
Abe Keith Y.
Publication year - 1995
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(95)00067-j
Subject(s) - cimetidine , clotrimazole , cytochrome p450 , nitric oxide , chemistry , cytochrome , hepatocyte , enzyme , non competitive inhibition , cytokine , messenger rna , biochemistry , microbiology and biotechnology , biology , pharmacology , immunology , in vitro , gene , antifungal , organic chemistry
To investigate the role of the cytochrome P‐450 system in NO synthesis, cytochrome P‐450IIIA, IIE and IA activities were specifically inhibited by cimetidine (IIIA), clotrimazole (IIIA), benzoflavone (IA) and disulfiram (IIE) in a model of cultured rat hepatocytes. Cytokine‐induced NO synthesis was significantly decreased in the presence of cimetidine and clotrimazole. Kinetic analysis revealed a non‐competitive mode of inhibition ( K i = 21 mM, cimetidine; K i = 13 μ M, clotrimazole). Reverse transcriptase‐PCR and immunoblot analysis revealed no significant change in steady state levels of iNOS mRNA and protein expression with P‐450IIIA inhibition. Purified iNOS enzyme activity was not altered. These data suggest that cytokinemediated hepatocyte synthesis of NO is dependent upon P‐450IIIA activity, which functions in a post‐translational capacity.