RP7 Ecotoxicogenomics of Emerging Chemical Issues
Thursday, 17 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(BEN-1117-833820) Changes in gene and protein expression in zebrafish (Danio rerio) following exposure to environmentally-relevant endocrine-disrupting compounds (EDCs).

Bencic, D.¹, Miracle, A.^{1, 2}, Lattier, D.¹, Lazorchak, J.¹, Denslow, N.³, Watanabe, K.⁴, Whitehead, T.⁵, Collette, T.⁵, Ankley, G.⁶, ¹ U.S. EPA, ORD, NERL, EERD, Cincinnati, OH, USA² 2Pacific Northwest National Laboratory, Richland, WA, USA³ Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL⁴ Department of Environmental and Biomolecular Systems, Oregon Health & Science University, Beaverton, OR, USA⁵ U.S. EPA, ORD, NERL, ERD, Athens, GA, USA⁶ U.S. EPA, ORD, NHEERL, MED, Duluth, MN, USA

ABSTRACT- Endocrine-disrupting chemicals (EDCs) are increasingly being reported in waterways worldwide and have been shown to affect fish species by disrupting numerous aspects of development, behavior, reproduction, and survival. Furthermore, new data have suggested that the reduced reproductive fitness resulting from EDC exposure may have a significant impact at biological levels beyond the individual, such as the population level. In this study, we examined the effects of the synthetic steroids 17-ethinylestradiol (EE₂) and 17-trenbolone (trenbolone) on gene and protein expression in the liver and gonads of reproductively mature zebrafish (Danio rerio). These compounds are highly specific and potent agonists of estrogen and androgen receptors, respectively, and are used extensively in the U.S. as an active ingredient in many oral contraceptives (EE₂) or a growth promoter in beef cattle (trenbolone). Both have been detected in aquatic environments and are therefore relevant as environmental contaminants. Fish were exposed to two concentrations of EE₂ (30 or 100 ng/L) or trenbolone (0.3 or 3.0 g/L) or control water for up to 96 hours in a flow-through system. Changes in the transcriptome and proteome were measured using microarrays followed by QPCR validation and two-dimensional gel electrophoresis followed by peptide analysis via mass spectroscopy, respectively. The differential expression profiles will provide molecular diagnostic and predictive biomarkers for risk assessment, and along with metabolite profiles and whole organism endpoints from ongoing projects, will further enhance source-to-outcome linkages and support computational modeling. Integration of these zebrafish gene and protein expression data sets with definitive tests in the fathead minnow (Pimephales promelas) will help establish toxicity pathways of environmentally-relevant responses in a systems- and population-modeling context. Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.

Key words: EDCs, genomics, proteomics, zebrafish