Collapse of a fish population after exposure to a synthetic estrogen
Collapse of a fish population after exposure to a synthetic estrogen
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DOI：
10.1073/pnas.0609568104
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发表时间：
2007-05-22
影响因子：
11.1
通讯作者：
Flick, Robert W.
中科院分区：
文献类型：
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作者：
Kidd, Karen A.;Blanchfield, Paul J.;Flick, Robert W.
城市废水是一种复杂的混合物，含有雌激素和雌激素模拟物，已知会影响野生鱼类的生殖健康。一些废水排放下游的雄性鱼类会在其睾丸中产生卵黄蛋白原 (VTG)（一种通常由雌性在卵母细胞成熟过程中合成的蛋白质）和早期卵子，这种女性化归因于雌激素物质的存在，例如天然雌激素 [雌酮或 17 β-雌二醇 (E2)]（用于节育的合成雌激素） 药丸 [17 α-乙炔雌二醇 (EE2)] 或较弱的雌激素模拟物，例如水中的壬基酚。尽管有广泛的证据表明雄性鱼类正在雌性化，但尚不清楚这些低水平的长期暴露是否会对野生种群的可持续性产生不利影响。我们在加拿大安大略省西北部的实验湖区 (ELA) 进行了一项为期 7 年的全湖实验，结果表明，黑头鲦鱼 (Pimephalespromelas) 长期接触低浓度 (5-6 ng-L-1) 强效 17 α-乙炔雌二醇，会通过产生卵黄蛋白原 mRNA 和蛋白质而导致雄性雌性化，影响 雄性的双性和雌性的卵子发生改变证明了性腺的发育，最终导致该物种在湖中几乎灭绝。我们的观察表明，在淡水中观察到的雌激素及其模拟物的浓度会影响野生鱼类种群的可持续性。
Municipal wastewaters are a complex mixture containing estrogens and estrogen mimics that are known to affect the reproductive health of wild fishes. Male fishes downstream of some wastewater out falls produce vitellogenin (VTG) (a protein normally synthesized by females during oocyte maturation) and early-stage eggs in their testes, and this feminization has been attributed to the presence of estrogenic substances such as natural estrogens [estrone or 17 beta-estradiol (E2)], the synthetic estrogen used in birth-control pills [17 alpha-ethynylestradiol (EE2)], or weaker estrogen mimics such as nonylphenol in the water. Despite widespread evidence that male fishes are being feminized, it is not known whether these low-level, chronic exposures adversely impact the sustainability of wild populations. We conducted a 7-year, wholelake experiment at the Experimental Lakes Area (ELA) in northwestern Ontario, Canada, and showed that chronic exposure of fathead minnow (Pimephalespromelas) to low concentrations (5-6 ng-L-1) of the potent 17 alpha-ethynylestradiol led to feminization of males through the production of vitellogenin mRNA and protein, impacts on gonadal development as evidenced by intersex in males and altered oogenesis in females, and, ultimately, a near extinction of this species from the lake. Our observations demonstrate that the concentrations of estrogens and their mimics observed in freshwaters can impact the sustainability of wild fish populations.