Centre for Fish and Wildlife Health, University of Bern, Bern, Switzerland.
Gen Comp Endocrinol. 2013 Sep 15;191:190-201. doi: 10.1016/j.ygcen.2013.05.015. Epub 2013 Jun 11.
Research on endocrine disruption in fish has been dominated by studies on estrogen-active compounds which act as mimics of the natural estrogen, 17β-estradiol (E2), and generally exert their biological actions by binding to and activation of estrogen receptors (ERs). Estrogens play central roles in reproductive physiology and regulate (female) sexual differentiation. In line with this, most adverse effects reported for fish exposed to environmental estrogens relate to sexual differentiation and reproduction. E2, however, utilizes a variety of signaling mechanisms, has multifaceted functions and targets, and therefore the toxicological and ecological effects of environmental estrogens in fish will extend beyond those associated with the reproduction. This review first describes the diversity of estrogen receptor signaling in fish, including both genomic and non-genomic mechanisms, and receptor crosstalk. It then considers the range of non-reproductive physiological processes in fish that are known to be responsive to estrogens, including sensory systems, the brain, the immune system, growth, specifically through the growth hormone/insulin-like growth factor system, and osmoregulation. The diversity in estrogen responses between fish species is then addressed, framed within evolutionary and ecological contexts, and we make assessments on their relevance for toxicological sensitivity as well as ecological vulnerability. The diversity of estrogen actions raises questions whether current risk assessment strategies, which focus on reproductive endpoints, and a few model fish species only, are protective of the wider potential health effects of estrogens. Available - although limited - evidence nevertheless suggests that quantitative environmental threshold concentrations for environmental protection derived from reproductive tests with model fish species are protective for non-reproductive effects as well. The diversity of actions of estrogens across divergent physiological systems, however, may lead to and underestimation of impacts on fish populations as their effects are generally considered on one functional process only and this may underrepresent the impact on the different physiological processes collectively.
鱼类内分泌干扰的研究主要集中在雌激素活性化合物上，这些化合物作为天然雌激素 17β-雌二醇（E2）的模拟物，通常通过与雌激素受体（ER）结合并激活来发挥其生物学作用。雌激素在生殖生理学中起着核心作用，并调节（雌性）性分化。与此一致的是，大多数报道的鱼类暴露于环境雌激素的不良反应与性分化和生殖有关。然而，E2 利用多种信号机制，具有多方面的功能和靶点，因此环境雌激素对鱼类的毒理学和生态学影响将超出与生殖相关的影响。本综述首先描述了鱼类雌激素受体信号的多样性，包括基因组和非基因组机制以及受体串扰。然后，它考虑了鱼类中已知对雌激素有反应的一系列非生殖生理过程，包括感觉系统、大脑、免疫系统、生长，特别是通过生长激素/胰岛素样生长因子系统和渗透压调节。然后，在进化和生态背景下，探讨了鱼类物种之间雌激素反应的多样性，并对其在毒理学敏感性和生态脆弱性方面的相关性进行了评估。雌激素作用的多样性提出了这样一个问题，即当前的风险评估策略是否具有保护作用，这些策略侧重于生殖终点和少数几种模式鱼类，是否能保护更广泛的潜在雌激素健康影响。尽管可用的证据有限，但仍表明，从具有代表性的鱼类生殖测试中得出的定量环境保护阈值浓度对于非生殖效应也是具有保护作用的。然而，雌激素在不同生理系统中的作用的多样性可能会导致对鱼类种群的影响被低估，因为它们的作用通常仅考虑一个功能过程，这可能会低估对不同生理过程的综合影响。
