Combined effect of endocrine disruptors on reproductive success of aquatic organisms

生活在接受农业、工业和生活污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，如三丁基锡、多氯联苯或17β-雌二醇(E2)。据报告，从受污染地区采集的鱼类繁殖成功率下降，暴露于乙二醇胺的鱼类产卵减少。然而，很少有研究考虑EED对鱼类性行为的综合影响。因此，我们研究了EDE对日本青竹繁殖成功和性行为的综合影响。以含三氯二苯和多氯联苯(TBT PCB)的饲料(1μg g-1体重/d)和E_2(3.30μg g-1体重/d)为阳性对照，每天饲养青竹3周。繁殖成功通过产卵量和受精成功率来衡量。用p-…评价雄性动物的性行为。更多的是让一名女性注射前列腺素，这是众所周知的刺激男性青竹的性行为。用摄像机记录了1小时的行为，并分析了与雌性发生典型性行为(追随、求偶舞蹈和交配)的频率。与阴性对照相比，TBT多氯联苯和E2处理组的产卵量和受精成功率显著减少。此外，与对照鱼相比，处理雄鱼的性行为受到抑制，尽管处理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，这种干扰是用TBT多氯联苯处理的青竹产卵减少的原因之一。因此，一种包含青牡蛎性行为的生殖测试可能对检测内分泌功能障碍非常有用，特别是在EED组合诱导的情况下。在另一项实验中，将TBT(2μg/壳)注射到珍珠牡蛎壳中。注射后，取中肠腺、性腺、肌肉等组织进行TBT测定。结果表明，在中肠腺和性腺中浓度较高。因此，TBT可能会在壳中积累并影响其繁殖。较少

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