Research on mechanisms of CYP1A-induced toxicity suggests that EROD activity may not only indicate chemical exposure, but also may also precede effects at various levels of biological organization. EROD activity has proven value as a biomarker in a number of field investigations of bleached kraft mill and industrial effluents, contaminated sediments, and chemical spills.
Good candidate species for biomonitoring should have a wide range between basal and induced EROD activity (e.g., common carp, channel catfish, and mummichog). EROD induction in fish is well characterized, the most important modifying factors being fish species, reproductive status and age, all of which can be controlled through proper study design.
The various methods of EROD analysis currently in use yield comparable results, particularly when data are expressed as relative rates of EROD activity. Although certain chemicals may inhibit EROD induction/ activity, this interference is generally not a drawback to the use of EROD induction as a biomarker. A multitude of chemicals induce EROD activity in a variety of fish species, the most potent inducers being structural analogs of 2,3,7,8-tetracholordibenzo-p-dioxin. This review compiles and evaluates existing scientific information on the use, limitations, and procedural considerations for EROD activity (a catalytic measurement of cytochrome P4501A induction) as a biomarker in fish. We recommend the use of these two biochemical and cytological changes in intestines as specific biomarkers to indicate current and recent exposure of fish to BaP via oral intake.Įthoxyresorufin- O-deethylase ( EROD) activity in fish as a biomarker of chemical exposure These results further corroborate our earlier findings that induction of EROD activities in fish do not merely indicate exposure to BaP but also are correlated to harmful biological effects.
Importantly, intestinal EROD activity was significantly correlated to 2 degrees/3 degrees lysosome accumulation in enterocytes (r = 0.571, p < 0.001). Significant increase of 2 degrees/3 degrees lysosomes, as measured by Vv(lysosome, mucosa), was detected in young enterocytes of fish in the high-dosing group (12.5 microg/g fish/d) at exposure day 3 and persisted until recovery week 2. Conversely, hepatic EROD induction was weak and subsided rapidly in the exposed fish, signifying that hepatic EROD activity is not a good indicator of oral intake of BaP. A dose-response relationship was demonstrated between intestinal EROD activities and the levels of foodborne BaP. Intestinal EROD induction was rapid (within 3 d) and sustained in the BaP-exposed fish, while a fast recovery (within one week) was observed on withdrawal of BaP intake. Temporal changes of intestinal and hepatic ethoxyresorufin- O-deethylase ( EROD) activities and quantitative changes of secondary and tertiary (e.g., 2 degrees/3 degrees) lysosomes in enterocytes were compared for the juvenile grouper (Epinephelus coioides) on chronic exposure to foodborne benzopyrene (BaP) at two environmentally realistic levels (0.25 and 12.5 microg/g fish/d) over a four-week exposure and four-week depuration period. Temporal changes of ethoxyresorufin- o-deethylase ( EROD) activities and lysosome accumulation in intestine of fish on chronic exposure to dietary benzopyrene: linking erod induction to cytological effects. TEMPORAL TRENDS IN ETHOXYRESORUFIN- O-DEETHYLASE ACTIVITY OF BROOK TROUT (SALVELINUS FONTINALIS) FED 2,3,7,8-TETRACHLORODIBENZO-P-DIOXINĬhanges in ethoxyresorufin- O-deethylase ( EROD) activity were monitored through an extended 6-month dietary exposure to determine the relationship between EROD activity and uptake of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in brook trout, Salvelinus fontinalis.
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