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Cell‐specific CYP1A expression and benzo[ a ]pyrene adduct formation in gills of rainbow trout ( Oncorhynchus mykiss ) following CYP1A induction in the laboratory and in the field
Author(s) -
Jönsson Maria E.,
Brunström Björn,
Ingebrigtsen Kristian,
Brandt Ingvar
Publication year - 2004
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/03-211
Subject(s) - rainbow trout , pyrene , benzo(a)pyrene , gill , chemistry , salmo , microbiology and biotechnology , salmonidae , trout , biology , environmental chemistry , fish <actinopterygii> , fishery , organic chemistry
The effect of cytochrome P4501A (CYP1A)induction on cell‐specific benzo[ a ]pyrene (B a P) adduct formation was studied in rainbow trout ( Oncorhynchus mykiss ) gills. Fish preexposed to β‐naphthoflavone (βNF) or caged in a polluted river were exposed to waterborne 3 H‐benzo[ a ]pyrene ( 3 H‐B a P). The 3 H‐benzo[ a ]pyrene adducts in the gill filaments were localized by autoradiography and CYP1A protein by immunohistochemistry. Ethoxyresorufin O ‐deethylase (EROD) activity was measured using a gill filament‐based ex vivo assay. Branchial 3 H‐B a P binding and EROD activity were enhanced by exposure to βNF or to the river water, and completely blocked by the CYP1A inhibitor ellipticine. The predominant sites of adduct formation were in epithelium of the secondary lamellae and in epithelium of the efferent edge of the gill filament. In βNF‐exposed fish, the strongest CYP1A immunoreactivity was observed in differentiating cells and in pillar cells. In fish caged in the polluted river, strong CYP1A immunoreactivity was found in most cells in the secondary lamellae, whereas the primary lamellae were almost devoid of immunoreactivity. Our results reveal a discrepancy between the localization of CYP1A protein and B a P adducts in the gill. Consequently, other factors, such as bioavailability of waterborne polycyclic aromatic hydrocarbons (PAHs) to the target cells, are important for the localization of PAH adducts in the gill.