|
(18-64) Estrogenic effects of ethinylestradiol and dichlorobenzene on zebrafish (Danio rerio). Versonnen, Bram*,1, Arijs, Katrien1, Verslycke, Tim1, Janssen, Colin1, 1 Ghent University, Laboratory of Environmental Toxicology and Aquatic Ecology, Jozef Plateaustraat 22, Ghent, Belgium ABSTRACT- The estrogenicity of ethinylestradiol (EE) and o-, m- and p-dichlorobenzene (DCB) was evaluated with a yeast estrogenic screen (YES) and zebrafish vitellogenin assays. With the YES, p-DCB and m-DCB were found to be estrogenic, with p-DCB exhibiting the highest endocrine disruptive activity. Adult zebrafish were exposed to EE and the dichlorobenzenes for 2 weeks after which their blood vitellogenin (VTG) content was measured to examine the in vivo estrogenic activity of the these chemicals. Relative VTG concentrations in the blood samples were determined using protein electrophoresis. Gonadosomatic indices (GSI) and condition factors were also calculated. No effects on condition factors were observed, but elevated VTG levels and decreased female GSIs were found in fish exposed to ≥ 5 ng EE/l and in fish exposed to ≥ 10 mg p-DCB/l. O- and m-DCB did not significantly affect VTG levels and GSIs. In genereal, low GSIs coincided with high levels of VTG in the blood of female zebrafish, not only in EE and p-DCB exposed fish, but also in control fish. Further, the place of chlorine substitution appears to affect the estrogenic capacity of DCB. Key words: endocrine disruption, dichlorobenzene, vitellogenin, zebrafish |
