Over the last decade, increasing concern has been raised towards the potential of a diversity of environmental compounds to interfere with the endocrine system of humans and wildlife. Given the ubiquitous presence of these ‘endocrine disrupting chemicals’ (EDCs) in the aquatic environment – often at high concentrations – fish are inevitably exposed, resulting in a variety of adverse biochemical, physiological and reproductive effects, as demonstrated by researchers worldwide.
Nevertheless, and a result of the increasing awareness of the environmental risk of EDCs, there is a growing need for effective screening tools for the identification and assessment of endocrine disruptive effects in aquatic organisms. The diversity of potential target pathways of EDCs and the complex interplay with various endocrine-associated systems, added to an incomplete substantial knowledge of these intricate signaling pathways and networks in aquatic organisms, largely complicate a targeted detection of endocrine disruptive effects.
The principal goal of this study is to develop and evaluate a targeted gene expression assay for the identification and assessment of endocrine disruption in common carp (Cyprinus carpio). Within this framework, we aim to investigate the potential of various toxicogenomic techniques – in particular SSH-PCR and cDNA microarrays – to detect exposure to EDCs, and to identify toxic mechanisms of action of these compounds in a teleost species.
The following research questions are addressed: (1) is a toxicogenomics approach applicable to gain insight into the molecular basis of gender differences in fish, as a starting point to further explore mechanisms of action of EDCs?; (2) can gene expression signatures be applied to identify common estrogen-like activity, as well as unique compound-associated effects of estrogenic chemicals in fish?; (3) to what extent can different classes of EDCs encompassing various hormonal pathways, be distinguished based on their transcriptional profiles?; and (4) how does a genomic approach integrate into an ecologically relevant, complex test situation?
Through this approach we want to illustrate the value of the application of genomic tools in the context of environmental toxicology, in particular the endocrine disruption issue. This will lead to a better understanding of the ecotoxicological risk of EDCs, and will aid in the identification and classification of these compounds.
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