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(P540) Vitellogenin Gene Expression in Fathead Minnows Exposed to EE2 in a Whole Lake Dosing Experiment.
Lazorchak, James1, Flick, Robert*,1, Kidd, Karen2, Palace, Vince2, Hodge, Trevor2, 1 U.S. EPA, Cincinnati, OH2 Freshwater Institute, Winnipeg, Manitoba, Canada
ABSTRACT- A whole-lake endocrine disruption experiment was conducted by Fisheries and Oceans Canada at the Experimental Lakes Area (ELA), northwestern Ontario in 2001. This experiment examined population, organism and biochemical-level effects in lake trout, white sucker, fathead minnow, and pearl dace exposed to environmentally-relevant, (6 + 2.9 ng/L) concentrations of the synthetic estrogen, 17 Ethynylestradiol. The USEPA collaborated in this study by evaluating Vitellogenin gene expression (Vtg) in male fathead minnow livers: 1) from indigenous fish collected from the dosed and control lakes after 7, 9 and 12 weeks of dosing; 2) from indigenous minnows collected from the control lake and deployed for 1, 3, 7 and 13 days in the dosed and control lakes; and 3) from Cincinnati cultured minnows exposed to water collected from the both ELA lakes and shipped to Cincinnati. RT-PCR methods were used for measuring Vtg expression. In addition to water exposures, fry were exposed to sediment elutriates for 5 days. Gene expression in indigenous male fatheads collected at all time intervals from the dosed lake showed a constant level of gene expression. Gene expression was detected within 24-hrs after deployment of control fish into the treated lake and stayed elevated for the entire 13-day study. Highly variable gene expression was found in fry exposed to dosed lake sediments but no significant gene expression was found in fry exposed to control lake sediments. Results indicate that RT-PCR analyses of total RNA can be used to provide a rapid and timely estimate of exposure to estrogenic substances.
Key words: Estrogenic Substances, Gene Expression, Fathead Minnows, Experimental Lake Area Fish.
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