title: Prochloraz causes irreversible masculinization of zebrafish (Danio rerio).
abstract: The aim of the present study was to investigate the persistence of endocrine effects by prochloraz, a fungicide known to have multiple effects on the endocrine system of vertebrates. Since discontinuous exposure is particularly relevant in aquatic ecosystems, an exposure scenario with an exposure phase and a subsequent recovery period was chosen to assess the potential for reversibility of effects by prochloraz on the sexual development of zebrafish (Danio rerio). Zebrafish were exposed to different concentrations of prochloraz (10-300 μg/L) until 60 days post hatch (dph), which includes the period of sexual differentiation. For the subsequent 40 days, fish were either held in clean water for depuration or under further continuous exposure. Histological investigations of the gonads revealed persistent effects on sexual differentiation. The sex ratio was skewed towards males and significantly more intersex individuals were found after exposure to prochloraz at 60 dph. No intersex fish, but masculinized sex ratios were still present after the depuration period, documenting that prochloraz irreversibly affects the sexual development of zebrafish.
authors.affiliation: Centre for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, PO Box 8466, CH-3001, Bern, Switzerland. lisa.baumann@vetsuisse.unibe.ch.|Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany. lisa.baumann@vetsuisse.unibe.ch.
authors.forename: Lisa
authors.initials: L
authors.lastname: Baumann
authors.affiliation: Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany. susanne.knoerr@gmx.de.
authors.forename: Susanne
authors.initials: S
authors.lastname: Knörr
authors.affiliation: Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany. susanne.keiter@cos.uni-heidelberg.de.
authors.forename: Susanne
authors.initials: S
authors.lastname: Keiter
authors.affiliation: Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany. tina.nagel@stud.uni-heidelberg.de.
authors.forename: Tina
authors.initials: T
authors.lastname: Nagel
authors.affiliation: Centre for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, PO Box 8466, CH-3001, Bern, Switzerland. helmut.segner@vetsuisse.unibe.ch.
authors.forename: Helmut
authors.initials: H
authors.lastname: Segner
authors.affiliation: Aquatic Ecology and Toxicology Section, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 504, 69120, Heidelberg, Germany. braunbeck@uni-hd.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Braunbeck
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D052244:Endocrine Disruptors / Q000633:toxicity*; D005260:Female; D007093:Imidazoles / Q000633:toxicity*; D008297:Male; D012733:Sex Differentiation / Q000187:drug effects; D012744:Sex Ratio; D046468:Sexual Development / Q000187:drug effects*; D014819:Vitellogenins / Q000378:metabolism; D015027:Zebrafish / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology
chemical_list: D052244:Endocrine Disruptors; D007093:Imidazoles; D014819:Vitellogenins; C045362:prochloraz
keywords: Aromatase inhibitor; Endocrine disruptor; Fungicide; Gonad histology; Sexual differentiation; Zebrafish