Estrogenic response of bisphenol A in rainbow trout (Oncorhynchus mykiss)

Bisphenol A (BPA) previously shows to possess xenoestrogenic activities was administered to rainbow trout (Oncorhynchus mykiss) through a continuos fl ow system. The estrogenic response expressed as the induction of vitellogen in (VTG) synthesis was measured during 12 days of exposure, using a direct sandwich ELISA. Quantification of internal liver and muscle concentrations of non-metabolised BPA was performed by LC-MS at the end of the exposure pe riod. A significant induction of the VTG synthesis was obtained at 500 mu g BPA/l exposure, although an increase in the ratio of responding animals wa s observed already between 40 and 70 mu g BPA/l. An increase in VTG levels was observed for the 500 mu g BPA/l group over the study period, whereas co nstant or decreasing levels could be detected in the low exposure groups be tween days 6 and 12. Average internal liver concentrations of BPA increased from 0.22 to 4.36 mu g/g for the 10-500 mu g BPA/l groups. However, BPA co uld not be detected in muscle tissue below an exposure level of 70 mu g BPA /l. A dose response relationship was established between the interval liver concentrations of BPA and the corresponding VTG responses, with a P < 0.00 1 and a correlation coefficient of 0.66. (C) 2000 Elsevier Science B.V. All rights reserved.