title: Dose-dependent compensation responses of the hypothalamic-pituitary-gonadal-liver axis of zebrafish exposed to the fungicide prochloraz.
abstract: Compensation responses and adaptability of hypothalamic-pituitary-gonadal (HPG) axis have been reported in fish exposed to model chemicals, however due to its importance in predictive toxicology further study was needed to elucidate details of the integrated responses to model chemicals. Transcriptional profiles of the hypothalamic-pituitary-gonadal (HPG) axis and concentrations of 17β-estradiol (E2) in plasma were measured in male and female zebrafish that had been exposed to one of seven concentrations of the fungicide, prochloraz: low (1, 3 or 10μg/L), medium (30 or 100μg/L) or high concentrations (300 or 1000μg/L) for 4 days. In zebrafish exposed to the low and medium concentrations of prochloraz, compensation responses of the HPG axis through transcription, occurred in brain (up-regulation of gnrh, gnrhr and lhβ) and both brain and gonad (up-regulation of steroidogenic genes), respectively. Concentrations of E2 in plasma and expression of estrogen receptor 1 (er1) and vitellogenins (vtgs) in liver did not change. This result suggested that compensatory responses were successful in maintaining homeostasis. In zebrafish exposed to the two greatest concentrations, compensatory responses occurred in brain, gonad and liver through up-regulation of er2β, but it failed to maintain concentration of E2 in blood plasma and expression of er1 and vtgs in liver. Collectedly, the results observed in this study allowed characterization of dose-dependent compensatory responses along the HPG axis and liver and identified key linkages between compensatory responses occurring in brain, gonad and liver after exposure to prochloraz.
authors.affiliation: College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Dang
authors.affiliation: Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong, China; School of Biological Sciences, University of Hong Kong, SAR, Hong Kong, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China.
authors.forename: John P
authors.initials: JP
authors.lastname: Giesy
authors.affiliation: College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: whtjwjh@163.com.
authors.forename: Jianghua
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: liuchunshengidid@126.com.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Liu
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects; D004703:Endocrine System / Q000187:drug effects*; D004781:Environmental Exposure; D004958:Estradiol / Q000097:blood; D047628:Estrogen Receptor alpha / Q000235:genetics; D005260:Female; D005659:Fungicides, Industrial / Q000633:toxicity; D005786:Gene Expression Regulation / Q000187:drug effects*; D006066:Gonads / Q000187:drug effects; D007031:Hypothalamus / Q000187:drug effects; D007093:Imidazoles / Q000633:toxicity*; D008099:Liver / Q000187:drug effects; D008297:Male; D010902:Pituitary Gland / Q000187:drug effects; D014819:Vitellogenins / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000633:toxicity; D015027:Zebrafish / Q000502:physiology*
chemical_list: D047628:Estrogen Receptor alpha; D005659:Fungicides, Industrial; D007093:Imidazoles; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; D004958:Estradiol; C045362:prochloraz
keywords: Aromatase inhibitor; Compensation responses; HPG axis; Prochloraz; Zebrafish