title: Cytochrome P450 (CYP1A) induction and DNA adducts in a rat hepatoma cell line (Fao), exposed to environmentally relevant concentrations of organic compounds, singly and in combinations.
abstract: Cytochrome P4501A (CYP1A) induction and DNA adduct formation were evaluated in the rat hepatoma cell line Fao, as biomarkers of exposure to organic compounds. Cells were exposed to environmentally relevant concentrations of benzo[a]pyrene (B[a]P) or 3,3',4,4'-tetrachlorobiphenyl (TCB), and to combinations of B[a]P and TCB. Both B[a]P and TCB induced CYP1A proteins in a concentration-dependent relationship, up to concentrations of 10 and 1 μM, respectively, detected by Western blotting. DNA adducts, analyzed by (32)P-postlabeling, were found at the highest concentrations of B[a]P (1 and 10 μM). No adducts were found in cells exposed to 0.1 μM TCB alone. The cotreatment of TCB and B[a]P indicated an increase in DNA adduct formation, compared with B[a]P, but no further induction of CYP1A protein compared with TCB alone. This study suggests that Western blotting and (32)P-postlabeling might be suitable methods for detecting CYP1A protein induction and DNA adducts, respectively, after exposure to environmentally relevant concentrations of organic compounds.
authors.affiliation: Department of Botany, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
authors.forename: Lene
authors.initials: L
authors.lastname: Ostby
authors.forename: Ase
authors.initials: A
authors.lastname: Krøkje