Combined effect of endocrine disruptors on reproductive success of aquatic organisms

生活在接受农业、工业和生活废水的沿海地区的鱼类暴露于各种亚致死水平的环境内分泌干扰物（EEDs），如三丁基锡（TBT）、多氯联苯（PCB）或17β-雌二醇（E2）。据报告，从受污染地区收集的鱼类的繁殖成功率下降，并观察到接触EEDs的鱼类产卵减少。然而，很少有研究考虑EEDs对鱼类性行为的综合影响。本研究以日本青鳉（Oryziaslatipes）为材料，研究了EEDs对青鳉生殖成功率和性行为的综合影响，以TBT和PCBs（TBT+PCBs：1μg/g体重/d）和E2（3.30μg/g体重/d）为阳性对照，连续饲养3周。繁殖成功率通过产卵数量和受精成功率来衡量。雄性的性行为通过p 关于我们 让雌性青鳉与注射了前列腺素的雌性青鳉交配，前列腺素可以刺激雄性青鳉的性行为。结果表明，与阴性对照组相比，TBT+PCBs和E2处理组的产卵量和受精成功率均显著降低。此外，与对照鱼相比，处理过的雄性的性行为受到抑制，尽管在处理过的雄性的正常游泳速度中没有观察到变化。这些数据表明，性行为受损是由内分泌紊乱引起的，这种紊乱是用三丁基锡化合物+多氯联苯处理的青鳉产卵减少的原因之一。因此，包括青鳉性行为在内的生殖试验可能非常有助于检测内分泌功能障碍，特别是由EEDs组合引起的内分泌功能障碍。注射后，收集组织（中肠腺、性腺、肌肉等），进行三丁基锡化合物测定。结果表明，在中肠腺和性腺中观察到高浓度。因此，TBT可能在贝壳中积累，影响贝壳的繁殖。少

Fish inhabiting coastal areas receiving agricultural, industrial, and domestic wastewaters have been exposed to various sublethal levels of environmental endocrine disruptors (EEDs) such as tributyltin (TBT), polychlorinated biphenyls (PCBs), or 17β-estradiol (E2). A decrease in reproductive success in fish collected from contaminated areas has been reported, and a reduction in spawning in fish exposed to EEDs has been observed. However, few studies have considered the combined effects of EEDs on the sexual behavior of fish. Therefore, we investigated the combined effects of EEDs on reproductive success and sexual behavior in Japanese medaka, Oryzias latipes.Pairs of Japanese medaka were fed daily on diets containing TBT and PCBs (TBT+PCBs) : 1μg g-1 body weight per day) and E2 (3.30μg g-1 body weight per day), as a positive control, for 3 weeks. Reproductive success was measured by the number of eggs spawned and fertilization success. The sexual behavior of the males was assessed by p … More airing them with a female injected with prostaglandin, which is known to stimulate sexual behavior in male medaka. The behavior of the fish was recorded by video camera for one hour and analyzed for frequencies of typical sexual behaviors (following, courting dance, and crossing) performed toward the female.A significant reduction in the number of eggs spawned and fertilization success was observed in those treated with TBT+PCBs and with E2, when compared with negative controls. Furthermore, the sexual behavior of treated males was suppressed compared to that of the control fish, although no change was observed in the normal swimming speed of the treated males. These data show that impairment of sexual behavior is caused by endocrine disruption, and that this disruption is one of the causes of reduced spawning in medaka treated with TBT+PCBs. Accordingly, a reproductive assay that includes sexual behavior of medaka might be highly useful for detecting endocrine dysfunction, especially as induced by a combination of EEDs.In another experiment, TBT (2μg/shell) was injected to pearl oyster shell. After injection, tissues (mid-gut gland, gonad, muscle, etc) were collected and subjected to the determination of TBT. As a results, high concentration were observed in mid-gut gland and gonad. Thus, TBT might be accumulated in shell and affected its reproduction. Less