Combined effect of endocrine disruptors on reproductive success of aquatic organisms

生活在接收农业、工业和家庭废水的沿海地区的鱼类已经暴露于各种亚致死水平的环境内分泌干扰物（ed），如三丁基锡（TBT）、多氯联苯（pcb）或17β-雌二醇（E2）。据报道，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ed的鱼类产卵减少。然而，很少有研究考虑到eed对鱼类性行为的综合影响。因此，我们研究了eed对日本稻（Oryzias latipes）繁殖成功率和性行为的综合影响。试验对日本尾田鼠每天饲喂含TBT和多氯联苯（TBT+多氯联苯）：1μg -1体重/天，E2 （3.30μg -1体重/天）为阳性对照的饲粮，连续3周。繁殖成功是通过产卵数量和受精成功来衡量的。研究人员用注射前列腺素的雌性蚊子来评估雄性蚊子的性行为，前列腺素可以刺激雄性蚊子的性行为。用摄像机记录鱼的行为一小时，并分析对雌性进行的典型性行为（跟随，求爱舞蹈和交配）的频率。与阴性对照相比，经TBT+多氯联苯和E2处理的受精卵数量和受精成功率显著降低。此外，与对照鱼相比，治疗后雄鱼的性行为受到抑制，尽管治疗后雄鱼的正常游泳速度没有变化。这些数据表明，性行为的损害是由内分泌干扰引起的，而这种干扰是经TBT+多氯联苯处理的鳉鱼产卵减少的原因之一。因此，包括medaka的性行为的生殖试验可能对检测内分泌功能障碍非常有用，特别是由eed组合引起的内分泌功能障碍。在另一个实验中，将TBT （2μg/壳）注射到珍珠牡蛎壳中。注射后收集组织（中肠腺、性腺、肌肉等），测定TBT。结果表明，在中肠腺和性腺中可见高浓度。因此，TBT可能在壳中积累，影响其繁殖。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