Xenobiotic and steroid biotransformation enzymes in Atlantic salmon ( Salmo salar) liver treated with an estrogenic compound, 4‐nonylphenol

• Published in: Environmental Toxicology and Chemistry
• Main Authors: Arukwe, Augustine, Förlin, Lars, Goksøyr, Anders
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1997
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1002/etc.5620161220; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fetc.5620161220; https://setac.onlinelibrary.wiley.com/doi/pdf/10.1002/etc.5620161220

Abstract 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.