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Xenobiotic and steroid biotransformation enzymes in Atlantic salmon ( Salmo salar ) liver treated with an estrogenic compound, 4‐nonylphenol
Author(s) -
Arukwe Augustine,
Förlin Lars,
Goksøyr Anders
Publication year - 1997
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 - 10.1002/etc.5620161220
Subject(s) - salmo , xenobiotic , cyp3a , cytochrome p450 , biotransformation , microsome , steroid , enzyme , nonylphenol , medicine , isozyme , chemistry , endocrinology , juvenile , biology , metabolism , estrogen , microsoma , biochemistry , hormone , fish <actinopterygii> , environmental chemistry , fishery , ecology
Hepatic microsomal biotransformation reactions with xenobiotic and steroid substrates have been investigated in 4‐non‐ylphenol (NP; 1, 5, 25, and 125 mg/kg body weight)‐treated juvenile Atlantic salmon ( Salmo salar ), in addition to control and estradiol‐17β (5 mg/kg, positive control)‐treated fish. Treatment of juvenile salmon with NP caused an initial increase and an apparent dose‐dependent decrease in progesterone 6β‐, 16α, and 17α‐hydroxylase activities in liver microsomes. 7‐Ethoxyresorufin O ‐deethylase and UDP‐glucuronosyltransferase activities were also reduced. Plasma levels of estradiol‐17β (E 2 ) were lowered 24–43% as a result of NP treatment. Immunochemical analysis of CYP1A, CYP2K‐like, and CYP3A‐like proteins showed 18%, 47%, and 30% reductions in enzyme‐linked immunosorbent assay absorbance levels, respectively, in the groups treated with 125 mg NP/kg fish. The group treated with E 2 also showed similar reductions. In summary, the present study has demonstrated variations in steroid hydroxylases, cytochrome P450 isozymes, and conjugating enzyme levels in NP‐treated juvenile salmon. These results represent a novel aspect of NP effects not previously demonstrated with an environmental estrogen in any fish species or lower vertebrate.