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PH01 Endocrine Disruption
(PH003) Persistent Bioaccumulative Contaminants and Biomarker Response in Columbia River White Sturgeon.
Paar, J1, Gundersen, D1, Kushner, L1, Fink, A1, Watterson, S1, Penn Boris, L1, Schreck, C2, Feist, G2, Webb, M2, Foster, E3, 1 Environmental Science Program, Pacific University, Forest Grove, OR, USA2 Department of Fisheries & Wildlife, Oregon State University, Corvallis, OR, USA3 Department of Environmental Quality, Portland, OR, USA
ABSTRACT- Chronic exposure to persistent bioaccumulative contaminants has been shown to contribute to endocrine disruption in many organisms. It is hypothesized that these contaminants may be contributing to poor reproductive success of Columbia River white sturgeon. Specifically, sturgeon livers and gonads were examined histologically and chlorinated pesticide levels were determined via GC-ECD from fish collected from the Columbia River estuary and pools above Bonneville, The Dalles, and John Day dams. Pesticide analysis detected the organochlorine contaminant, p,p′-DDE, most frequently and at the highest concentration. While p.p′-DDE levels were higher in fish from the Bonneville site, plasma vitellogenin levels (Vtg), measured using ELISA, were significantly higher in John Day and The Dalles males compared to other sites. Testosterone (T) and 11-ketotestosterone (KT) were measured using RIA, and the gonadosomatic index (GSI) was determined. Male plasma T and KT levels and GSI were negatively correlated with liver p,p′-DDE. In males, hepatic cytochrome P450 3A (CYP3A) levels, as determined by Western blot analysis, were positively correlated with p,p′DDE and negatively correlated with plasma androgens. Injection with 10 mg/kg p,p′-DDE in farm-raised juvenile sturgeon induced CYP3A levels within 1 week, indicating the potential use of this isozyme as a biomarker for p,p′-DDE exposure. Muscle, liver, gonad mercury concentrations, measured with CVAA, revealed measurable mercury levels in all muscle samples, with over 13% of these samples exceeding 0.5 ppm. Western blot analysis of liver metallothionein demonstrated that this enzyme was also positively correlated with liver mercury concentration. Results of these studies will be discussed with respect to their role in endocrine disruption and biomarker response in white sturgeon.
Key words: Biomarker, Endocrine disruption, Mercury, DDE
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