Pawlowski S, van Aerle R, Tyler C R, Braunbeck T
Department of Zoology, University of Heidelberg, Im Neuenheimer Feld 230, D-69120 Heidelberg, Germany.
Ecotoxicol Environ Saf. 2004 Mar;57(3):330-45. doi: 10.1016/j.ecoenv.2003.07.019.
To contribute to the development and evaluation of a practical and cost-effective in vivo testing system for endocrine disruption (specifically environmental estrogens), the effects of 17alpha-ethinylestradiol (EE2) were assessed in a gonadal recrudescence assay with the fathead minnow (Pimephales promelas). Mature male and female fathead minnows were kept first at 15 degrees C on a 8 h light/16 h dark regime and then transferred to 25 degrees C and a 16 h light/8 h dark regime to induce gonadal recrudescence. They were then exposed to various nominal concentrations of the synthetic estrogen EE2 (0, 0.1, 1, 3, 10, 100 ng/L). After 3 weeks of chemical exposure, effects on plasma vitellogenin (VTG), secondary sex characteristics, gonad growth (gonadosomatic index; GSI), and condition factor were assessed. Additionally, the effects on liver and gonad tissue morphology were investigated by means of light (LM) and electron microscopy (EM). Reproductive output (egg production) and fertilization rate were measured during a subsequent 3-week period in breeding adults maintained in clean water. Exposure to EE2 resulted in a significant decrease in GSI, condition factor, and number of batches of eggs and their fertilization rate at EE2 exposure concentrations between 10 and 100 ng/L. A reduction in the extent of parenchymatic areas in ovaries and ultrastructural changes in the livers of females could be detected at EE2 concentrations > or =3 ng/L. The lowest observed effective concentration (LOEC) of EE2 for plasma VTG induction in both sexes and for ultrastructural changes in the testes and livers was 1 ng/L. A significant increase in the mean number of eggs spawned per pair occurred at EE2 exposure doses of 0.1 and 1 ng/L. However, at higher EE2 concentrations, a dose-dependent decrease in the mean number of eggs per pair was apparent. Therefore, the LOEC for a biological effect of EE2 in the fathead minnow using the selected endpoints in the recrudescence assay was 1 ng/L for biomarkers such as plasma VTG and number of tubercles, and 0.1 ng/L for an increased number of eggs spawned per pair.
为推动实用且具成本效益的内分泌干扰物（特别是环境雌激素）体内测试系统的开发与评估，在黑头呆鱼（Pimephales promelas）的性腺再发育试验中评估了17α-乙炔雌二醇（EE2）的影响。成熟的雄性和雌性黑头呆鱼首先饲养在15摄氏度、8小时光照/16小时黑暗的条件下，然后转移到25摄氏度、16小时光照/8小时黑暗的条件下以诱导性腺再发育。之后，它们被暴露于不同标称浓度的合成雌激素EE2（0、0.1、1、3、10、100纳克/升）。化学暴露3周后，评估对血浆卵黄蛋白原（VTG）、第二性征、性腺生长（性腺体指数；GSI）和条件因子的影响。此外，通过光学显微镜（LM）和电子显微镜（EM）研究对肝脏和性腺组织形态的影响。在随后3周内，对饲养在清洁水中的成年繁殖鱼测量生殖产量（产卵量）和受精率。暴露于EE2导致在EE2暴露浓度为10至100纳克/升时，GSI、条件因子以及卵批次数量及其受精率显著下降。在EE2浓度≥3纳克/升时，可检测到雌性卵巢实质区域范围缩小以及肝脏超微结构变化。EE2对两性血浆VTG诱导以及睾丸和肝脏超微结构变化的最低观察到的有效浓度（LOEC）为1纳克/升。在EE2暴露剂量为0.1和1纳克/升时，每对产卵的平均数量显著增加。然而，在较高的EE2浓度下，每对卵的平均数量明显呈剂量依赖性下降。因此，在性腺再发育试验中，使用选定终点时，EE2对黑头呆鱼产生生物学效应的LOEC，对于血浆VTG和瘤数量等生物标志物为1纳克/升，对于每对产卵数量增加为0.1纳克/升。
