CYTOCHROME P-4502E1-DEPENDENT FORMATION OF TRIFLUOROACETYL ADDUCTS FROM HALOTHANE BY TRANSDUCED HEPG2 CELLS

E-9 cells, a HepG2 cell line that has the alcohol-inducible human cyto chrome P-4502E1 (CYP2E1) cloned into its genome, was tested for its ab ility to produce trifluoroacetyl (TFA) adducts from the metabolism of halothane. The metabolism of halothane results in the production of TF A halide that can readily react with cellular proteins to form TFA add ucts, which can be detected by antibodies directed against them. E-9 c ells formed TFA adducts when incubated with halothane. The major consi stent bands that were detected were of molecular weights of similar to 50, 78, and 100 kDa. The formation of these adducts was dependent on halothane concentration and time of incubation with halothane, MV-5 ce lls, the control cell line that has the viral vector without the P-450 , did not produce any adducts. Inhibitors of CYP2E1 function, such as 4-methylpyrazole, inhibited adduct formation, Furthermore, phorbol est ers, Which have been shown to increase the CYP2E1 level in this cell l ine, increased TFA adduct formation, This HepG2 cell line may be of va lue in studying the metabolism and toxicity of halothane in a human ce ll culture model.