title: Experimental paradigm for in-laboratory proxy aquatic studies under conditions of static, non-flow-through chemical exposures.
abstract: Endocrine-disrupting chemicals (EDCs) such as 17α-ethynylestradiol, 17β-estradiol, estrone, and para-nonylphenol have been measured in wastewater-treatment plant effluents, surface waters, sediments, and sludge and have been shown to induce liver-specific vitellogenin (vtg) messenger RNA in male fathead minnows (Pimephales promelas). The purpose of the present study was to establish minimal concentrations of select EDCs necessary to induce transcription of vtg in 48-h static renewal exposures, as measured by quantitative real-time thermal cycle amplification. Adult males were exposed to 17α-ethynylestradiol, 17β-estradiol, estrone, and para-nonylphenol. Dose-dependent increases in vtg expression were significant with all chemicals tested. The lowest concentrations of these chemicals to induce measurable vtg expression, with significant difference from respective controls, were 17α-ethynylestradiol, 2.2 ng L(-1); para-nonylphenol, 13.9 μg L(-1); 17β-estradiol, 42.7 ng L(-1); and estrone, 46.7 ng L(-1), measured as 48-h average concentrations. The present experiments were designed to frame a commonly acceptable approach for investigators who conduct static, in-laboratory proxy environmental aquatic exposures. The present study highlights the need for investigators to report in peer-reviewed submissions the observed concentration values for minimal induction levels when measuring molecular responses to chemical exposures by means of real-time polymerase chain reaction, quantitative polymerase chain reaction, or other "omic" technologies.
authors.affiliation: National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio.
authors.forename: Tirumuru V
authors.initials: TV
authors.lastname: Reddy
authors.affiliation: National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio.
authors.forename: Robert
authors.initials: R
authors.lastname: Flick
authors.affiliation: National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio.
authors.forename: James M
authors.initials: JM
authors.lastname: Lazorchak
authors.affiliation: Dynamac, US Environmental Protection Agency, Cincinnati, Ohio.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Smith
authors.affiliation: Dynamac, US Environmental Protection Agency, Cincinnati, Ohio.
authors.forename: Barry
authors.initials: B
authors.lastname: Wiechman
authors.affiliation: National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio.
authors.forename: David L
authors.initials: DL
authors.lastname: Lattier
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000378:metabolism*; D052244:Endocrine Disruptors / Q000032:analysis* / Q000633:toxicity; D004784:Environmental Monitoring / Q000379:methods*; D004958:Estradiol / Q000378:metabolism / Q000633:toxicity; D004970:Estrone / Q000032:analysis / Q000633:toxicity; D004997:Ethinyl Estradiol / Q000032:analysis / Q000633:toxicity; D008297:Male; D010636:Phenols / Q000032:analysis / Q000633:toxicity; D012722:Sewage / Q000737:chemistry; D014819:Vitellogenins / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D052244:Endocrine Disruptors; D010636:Phenols; D012722:Sewage; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; D004970:Estrone; D004997:Ethinyl Estradiol; D004958:Estradiol; C041594:4-nonylphenol
keywords: Contaminant of emerging concern; Ecotoxicogenomic; Endocrine-disrupting compound; Estrogenic compound; Transcriptomics