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Induction of mfo enzymes and production of bile metabolites in rainbow trout ( Oncorhynchus mykiss ) exposed to waste crankcase oil
Author(s) -
Upshall C.,
Payne J.F.,
Hellou J.
Publication year - 1993
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.5620121118
Subject(s) - rainbow trout , chemistry , enzyme inducer , kidney , enzyme assay , enzyme , zoology , biology , medicine , endocrinology , biochemistry , fish <actinopterygii> , fishery
It is difficult to assess the toxicological significance of complex mixtures of contaminants in the environment because of paucity of dose‐response studies. Rainbow trout ( Oncorhynchus mykiss ) were exposed per os to waste crankcase oil and analyzed for hydrocarbon classes, 26 polycyclic aromatic compounds (PACs) and 66 elements. MFO enzyme activity, measured as 7‐ethoxyresorufin O ‐deethylase (EROD) was induced in liver, kidney, and heart. The threshold level for induction in liver was approximately 3 mg of PACs (sum of 26 PACs) per kilogram fish. A dose‐response relationship was obtained for liver and kidney but not for the heart. In a time‐response study, liver, kidney, and heart MFO activity increased (14‐, 5‐, and 3‐fold, respectively), reaching a maximum between days 1 and 4, then decreased to basal levels by day 12. Analysis of bile metabolites, as gluc‐uronide and sulfate conjugates, showed a pattern similar to that displayed by MFO induction, possibly with a slight delay. This study establishes time‐ and dose‐response relationships for MFO enzyme induction and appearance of bile metabolites in fish exposed to an environmentally important source of PACs.