PARENT SESSION
18 - Endocrine Disruption
8:00 AM to 6:30 PM, Monday, 13 May 2002
Exhibition Area

(18-57) Induction of vitellogenesis in rainbow trout exposed to 17-ethinylestradiol: a method comparison.

Verslycke, Tim^*,1, Vandenbergh, Gert¹, Versonnen, Bram¹, Arijs, Katrien¹, Janssen, Colin¹, ¹ Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent, -

ABSTRACT- Juvenile rainbow trout (Oncorhynchus mykiss), were exposed to the synthetic estrogen 17-ethinylestradiol (EE2) through injection (1-10-25-50 g EE2/g wet weight/week) and water exposure (1-10-100 ng EE2/l). After 7 (injection and water exposure) and 14 days (only for water exposure), blood and plasma vitellogenin concentrations were quantified using indirect endpoints, i.e. plasma alkaline-labile phosphorus (ALP), plasma protein and plasma calcium. In addition the relative gonad (GSI) and liver weight (HSI) were recorded. Only fish injected with 50 g EE2/g fish exhibited a significantly higher gonad weight. No concentration-dependent changes in the HSI were detected in fish exposed via the water, but a significant dose-dependent increase of the HSI was observed in fish injected with EE2. Exposure of rainbow trout to EE2 had a significant effect on all three plasma parameters. The plasma protein, plasma phosphoprotein and plasma calcium concentrations were significantly higher after two weeks exposure to 100 ng EE2/l. Fish injected with 10, 25 and 50 g EE2/g ww exhibited an increased plasma protein concentration after 1 week. Compared to the control, plasma ALP and calcium levels were significantly higher in all EE2-injected fish. A significant and positive correlation was observed between all three plasma parameters. These findings indicate that both the plasma ALP and the plasma calcium assay have a similar sensitivity as that of available antibody-based assays (ELISA), at least in EE2 exposure studies and thus provide a rapid, simple and cost-effective

Key words: endocrine disruption, rainbow trout, vitellogenin, ethinylestradiol