Pickford Daniel B, Hetheridge Malcolm J, Caunter John E, Hall A Tilghman, Hutchinson Thomas H
AstraZeneca Global Safety, Health and Environment, Brixham Environmental Laboratory, Freshwater Quarry, Brixham, Devon TQ5 8BA, UK.
Chemosphere. 2003 Oct;53(3):223-35. doi: 10.1016/s0045-6535(03)00308-4.
A number of currently used industrial chemicals are estrogenic, and therefore have potential to disrupt sexual differentiation in vertebrate wildlife during critical developmental windows. We assessed the effect of larval exposure to bisphenol A (BPA) on growth, development and sexual differentiation of the gonad in the African Clawed frog, Xenopus laevis. Larvae were maintained in flow-through conditions at 22 +/- 1 degrees C and exposed to BPA at mean measured concentrations of 0.83, 2.1, 9.5, 23.8, 100, and 497 microg/l, from developmental stages 43/45-66 (completion of metamorphosis). Each test concentration, plus dilution water control (DWC) and positive control (17beta-estradiol (E2), 2.7 microg/l) employed four replicate test vessels with 40 larvae per tank. Individual froglets were removed from test vessels upon reaching stage 66, and the study was terminated at 90 days. Froglets were dissected and sex was determined by inspection of gross gonadal morphology. Test concentrations of BPA had no effect on survival, growth, developmental stage distributions at exposure days 32 and 62, or mean time to completion of metamorphosis, compared to DWC. Analysis of post-metamorphic sex ratio, determined by gross gonadal morphology, indicated no significant deviations from expected (50:50) sex ratio, in DWC or any BPA test concentration. In contrast, exposure of larvae to (E2) resulted in feminisation, with sex ratio deviating significantly (31% male, replicates pooled). Exposure to BPA in the concentration range 0.83-497 microg/l in flow-through conditions had no observable effect on larval growth, development or sexual differentiation (as determined by gross gonadal morphology) in this study.
目前使用的一些工业化学品具有雌激素活性，因此有可能在关键发育窗口期扰乱脊椎动物野生动物的性别分化。我们评估了非洲爪蟾（非洲爪蟾）幼体暴露于双酚A（BPA）对性腺生长、发育和性别分化的影响。幼体在22±1℃的流水条件下饲养，从发育阶段43/45至66（变态完成）暴露于平均测量浓度为0.83、2.1、9.5、23.8、100和497μg/L的BPA中。每个测试浓度，加上稀释水对照（DWC）和阳性对照（17β-雌二醇（E2），2.7μg/L），使用四个重复的测试容器，每个水箱中有40只幼体。幼蛙在达到66阶段时从测试容器中取出，研究在90天时终止。解剖幼蛙并通过检查性腺大体形态确定性别。与DWC相比，BPA的测试浓度对暴露第32天和62天的存活率、生长、发育阶段分布或变态完成的平均时间没有影响。通过性腺大体形态确定的变态后性别比例分析表明，DWC或任何BPA测试浓度与预期（50:50）性别比例均无显著偏差。相比之下，幼体暴露于（E2）导致雌性化，性别比例有显著偏差（雄性占31%，合并重复样本）。在本研究中，在流水条件下暴露于0.83-497μg/L浓度范围内的BPA对幼体生长、发育或性别分化（通过性腺大体形态确定）没有可观察到的影响。
