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Molecular Endpoints and Mixtures of EDCs in Fish
Citation:
DENSLOW, N. D., N. GARCIA-REYERO, K. J. KROLL, E. F. ORLANDO, K. H. WATANABE, M. S. SEPULVEDA, DAN VILLENEUVE, E. J. PEKINS, AND G. T. ANKLEY. Molecular Endpoints and Mixtures of EDCs in Fish. Presented at SOT 50th Annual Meeting, Washington, DC, March 06 - 10, 2011.
Impact/Purpose:
To document research results.
Description:
Microarray technology is a relatively novel tool in ecotoxicology and is beginning to be used for exposure and/or hazard characterization for ecological risk assessment. To develop a basis for this type of analysis, fathead minnows (Pimephales promelas) were treated with two binary mixtures: 17?-ethinylestradiol and the estrogen antagonist, ZM 189,154; and 17?-trenbolone (androgen) and the androgen antagonist, flutamide. Concentrations chosen were anchored to levels which affect cumulative egg production in 21-day fathead minnow reproduction assays. Unique gene expression fingerprints were identified in endocrine active tissues including brain, gonad and liver, which point to adverse outcome pathways. In the presence of excess antagonist, gene expression was reversed, but only for some genes, suggesting that the model compounds have additional activities beyond binding to soluble sex hormone receptors. Using the validated microarrays effluents from water treatment plants and animal agricultural areas were tested. Expression profiles were unique at each of the locations, suggesting that they each vary in their composition and complexity. Expression changes in key genes such as steroidogenic acute regulatory protein (StAR), estrogen receptors, among others illustrate the presence of endocrine disrupting chemicals. Pathway analysis illustrates toxicity pathways that may be of importance for complex effluents.