Estrogenic endocrine-disrupting chemicals are an increasing social concern, as they can reduce the reproductive activity of wildlife. The present study aimed to clarify the long-term effects of estradiol-17β (E2) on male reproductive activity in goldfish. Sexually mature male goldfish were implanted with a silicone capsule containing E2, and kept for 14 weeks or 15 weeks. The reproductive activity of these fish was individually traced. The percentage of fish with tubercles on opercula and pectoral fins and expressible milt started to decrease at 5 weeks after capsule implantation and remained at low levels. Inhibition of spawning activity by E2 occurred later than inhibition of the development of tubercles and milt production. Thirty percent of E2-treated fish showed no spawning at 15 weeks, whereas 70% of fish showed active spawning. The relationship between milt production and spawning activity revealed that some E2-treated fish performed active spawning behavior with no expressible milt because of the time lag of suppression between milt production and spawning activity. Therefore, environmental estrogen does not simply cause non-spawning males, but can also cause behaviorally active infertile males, which leads to failure of egg fertilization, resulting in a substantial decrease in population size in wild fish.

中文翻译：

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金鱼雌二醇对雄性生殖活动的抑制：表现出活跃产卵行为的不育雄性的出现

雌激素内分泌干扰化学物质越来越受到社会关注，因为它们会降低野生动物的繁殖活动。本研究旨在阐明雌二醇-17β (E2) 对金鱼雄性生殖活动的长期影响。性成熟的雄性金鱼被植入含有 E2 的硅胶胶囊，并保持 14 周或 15 周。这些鱼的繁殖活动被单独追踪。在囊植入后 5 周，鳃盖和胸鳍上有结节的鱼和可表达的鱼白的百分比开始下降，并保持在低水平。E2 对产卵活动的抑制晚于对块茎发育和白粉生产的抑制。30% 的 E2 处理鱼在 15 周时没有产卵，而 70% 的鱼显示产卵活跃。产卵量与产卵活动的关系表明，由于产卵量和产卵活动之间的抑制时间滞后，一些经 E2 处理的鱼表现出活跃的产卵行为，没有明显的产卵量。因此，环境雌激素不仅会导致雄性不产卵，还会导致行为活跃的雄性不育，从而导致卵子受精失败，导致野生鱼类种群数量大幅减少。