Levy Gregor, Lutz Ilka, Krüger Angela, Kloas Werner
Department of Inland Fisheries, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, Berlin 12587, Germany.
Environ Res. 2004 Jan;94(1):102-11. doi: 10.1016/s0013-9351(03)00086-0.
To evaluate possible estrogenic effects of bisphenol A (BPA) in an amphibian model, Xenopus laevis tadpoles were exposed to BPA and 17beta-estradiol (E2) during larval development. After metamorphosis, the gonadal phenotype was determined by gross morphology, and testes were further examined histologically to validate the results. BPA treatment altered the normal sex ratio toward females depending on the BPA concentrations added. Chemical analysis showed a time-dependent decline of BPA during semistatic exposure, indicating that BPA is taken up and metabolized to some extent by tadpoles. In addition, tadpoles were exposed to BPA and E2 for 2 weeks during sensitive stages of sexual differentiation. Afterward, the expression of an estrogenic biomarker, estrogen receptor (ER) mRNA, was assessed by semiquantitative RT-PCR. Both BPA and E2 up-regulated ER mRNA significantly. In conclusion, these results show clear evidence that BPA induces feminization in X. laevis tadpoles, revealing an estrogenic potency of BPA that influences sexual development in amphibians.
为了评估双酚A（BPA）在两栖动物模型中的潜在雌激素效应，非洲爪蟾蝌蚪在幼体发育期间被暴露于BPA和17β-雌二醇（E2）。变态后，通过大体形态学确定性腺表型，并对睾丸进行进一步的组织学检查以验证结果。BPA处理根据添加的BPA浓度使正常性别比向雌性倾斜。化学分析表明，在半静态暴露期间BPA呈时间依赖性下降，这表明蝌蚪在一定程度上摄取并代谢了BPA。此外，蝌蚪在性分化的敏感阶段被暴露于BPA和E2两周。之后，通过半定量RT-PCR评估雌激素生物标志物雌激素受体（ER）mRNA的表达。BPA和E2均显著上调ER mRNA。总之，这些结果清楚地表明BPA诱导非洲爪蟾蝌蚪雌性化，揭示了BPA影响两栖动物性别发育的雌激素活性。
