PM15 Biomarkers
Exhibit Hall
8:00 AM - Monday
(PM235) Induction of pollutant metabolizing enzymes in Lepomis species following PCB and PAH exposure.
Brammell, B1, Harmel, E1, Hitron, J1, Arzuaga, X1, Price, D1, Birge, W1, Elskus, A1, 1 University of Kentucky, Lexington, KY, U.S.A.
ABSTRACT- Although Lepomis species are abundant in a wide variety of habitats throughout North America and could be potentially valuable biomonitoring tools, few studies have examined the induction of pollutant biomarker enzymes in this genus. We hypothesized that induction of cytochrome P-450 1A, CYP1A (Phase I) and possibly glutathione S-transferase, GST and uridine diphosphate glucuronyltransferase, UDP-GT (Phase II) would serve as effective biomarkers of pollutant exposure in Lepomis. Three Lepomis species were exposed to model inducers in the laboratory representing the two major classes of CYP1A inducers, polychlorinated aromatic hydrocarbons and polycyclic aromatic hydrocarbons, at two doses in order to characterize the biochemical response of Lepomis species following pollutant exposure. Our results demonstrate species differences and differential sensitivity to the different classes of inducers in Lepomis. Longear sunfish and bluegill showed relatively low induction of CYP1A activity following exposure to 3,4,3',4'-tetrachlorobiphenyl, PCB77 (two to three fold induction over controls respectively) while green sunfish showed no induction relative to controls. In sharp contrast, CYP1A activity was highly induced in longear sunfish and bluegill (15 to 37 fold induction over controls respectively) following exposure to the model polyaromatic hydrocarbon inducer benzo-a-pyrene (BaP). Preliminary data indicates GST activity in bluegill remained unchanged following treatment with either compound while UDPGT activity was unaffected by BaP treatment in longear sunfish. Our results indicate differential sensitivity to the two main classes of CYP1A inducers in Lepomis species. These results suggest pollutant metabolizing enzymes may be poor bioindicators of PCB exposure in Lepomis species. However Lepomis may provide a vertebrate model for examining the regulation and consequences of differential pollutant sensitivity.
Key words: Lepomis, Biomarker, CYP1A