title: More accuracy to the EROD measurements--the resorufin fluorescence differs between species and individuals.
abstract: Ethoxyresorufin-O-deethylase (EROD) activity is a biomarker of exposure to planar aromatic hydrocarbons, and it is often measured from the S9 fraction. The effect of the liver S9 fraction of seven boreal freshwater fish species on the fluorescence of resorufin was studied. The S9 fractions diminished resorufin fluorescence by 40-80%, and there were large differences between species. Thus, using a resorufin standard curve without the S9 fraction leads to a large underestimation of the EROD activity. Therefore a microwell plate EROD method was developed that takes into account the effect of each sample on resorufin fluorescence. At least two mechanisms were involved in the decrease of the fluorescence: opaqueness of the sample, and enzymes (DT-diaphorase and plausibly NADPH-CYP450 oxidoreductase) that reduce resorufin to a non-fluorescent form.
authors.affiliation: Department of Biological and Environmental Sciences, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Jyväskylä, Finland. eeva-riikka.vehniainen@jyu.fi
authors.forename: Eeva-Riikka
authors.initials: ER
authors.lastname: Vehniäinen
authors.forename: Eija
authors.initials: E
authors.lastname: Schultz
authors.forename: Heli
authors.initials: H
authors.lastname: Lehtivuori
authors.forename: Janne A
authors.initials: JA
authors.lastname: Ihalainen
authors.forename: Aimo O J
authors.initials: AO
authors.lastname: Oikari
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D019363:Cytochrome P-450 CYP1A1 / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D004784:Environmental Monitoring / Q000379:methods*; D004789:Enzyme Activation / Q000187:drug effects; D005399:Fishes; D005453:Fluorescence; D015203:Reproducibility of Results; D013045:Species Specificity; D014874:Water Pollutants, Chemical / Q000494:pharmacology
chemical_list: D015415:Biomarkers; D014874:Water Pollutants, Chemical; D019363:Cytochrome P-450 CYP1A1