title: Effect of enzyme inducers on metabolism of 1-nitropyrene in human hepatoma cell line HepG2.
abstract: We measured the response of HepG2 cells to the classic cytochrome (cyt.) P-450 inducers 3-methylcholanthrene (3-MC) and phenobarbital (PB), by evaluating oxidative and/or reductive metabolism of the nitroarenes, 1-NP and 1,6-dinitropyrene (1,6-DNP), in control and induced cells. In HepG2 cells, 3-MC induces ring-hydroxylation of 1-NP, whereas PB stimulates its nitroreduction. PB induces NADPH-cyt. c reductase, but does not affect other cytosolic and microsomal enzymes which contribute to 1-NP nitroreduction in these cells. However, PB-inducible nitroreductase activity seems to be associated primarily with cyt. P-450 isoenzymatic form(s), as indicated by the requirement for NADPH and the response to specific inhibitors such as alpha-naphthoflavone and CO.
authors.affiliation: Dipartimento di Biochimica e Biotecnologie Mediche, Università degli Studi di Napoli, Italy.
authors.forename: M A
authors.initials: MA
authors.lastname: Belisario
authors.forename: A R
authors.initials: AR
authors.lastname: Arena
authors.forename: R
authors.initials: R
authors.lastname: Pecce
authors.forename: R
authors.initials: R
authors.lastname: Borgia
authors.forename: N
authors.initials: N
authors.lastname: Staiano
authors.forename: F
authors.initials: F
authors.lastname: De Lorenzo
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000378:metabolism*; D004790:Enzyme Induction; D006801:Humans; D008113:Liver Neoplasms / Q000201:enzymology / Q000378:metabolism*; D008748:Methylcholanthrene / Q000494:pharmacology*; D009153:Mutagens / Q000378:metabolism; D010634:Phenobarbital / Q000494:pharmacology*; D011721:Pyrenes / Q000378:metabolism*; D013347:Subcellular Fractions / Q000201:enzymology; D014407:Tumor Cells, Cultured
chemical_list: D009153:Mutagens; D011721:Pyrenes; D008748:Methylcholanthrene; C033309:1,6-dinitropyrene; C032668:1-nitropyrene; D010634:Phenobarbital