Toft Gunnar, Edwards Thea M, Baatrup Erik, Guillette Louis J
Institute of Biological Sciences, University of Aarhus, Aarhus, Denmark.
Environ Health Perspect. 2003 May;111(5):695-701. doi: 10.1289/ehp.6022.
Previous laboratory studies have demonstrated that estrogenic and antiandrogenic chemicals can alter several sexual characteristics in male poeciliid fishes. Whether similar disturbances occur under field conditions remains to be confirmed. Lake Apopka, Florida, is contaminated with numerous chemicals, some of which possess endocrine-disrupting activity. Male mosquitofish (Gambusia holbrooki) were collected monthly from December 2000 through May 2001 from Lake Apopka and two nearby reference lakes, Orange Lake and Lake Woodruff National Wildlife Refuge. Selected sexual characteristics were compared temporally and among lakes during the collection period. Male fish from Lake Apopka had slightly shorter gonopodia and on average 32 and 47% fewer sperm cells per milligram testis, when compared with the fish collected from Orange Lake and Lake Woodruff, respectively. The testes weights increased markedly during spring, with significantly smaller testes in fish from Lake Apopka than from Orange Lake, but surprisingly, the smallest testes occurred in males obtained from the Lake Woodruff population. The highest liver weights were found in the Lake Apopka population. Whole-body concentrations of testosterone and estradiol varied among months; the peak testosterone concentration occurred in January and was significantly lower in male fish from Lake Apopka compared with Orange Lake. The intensity of male courtship behavior was highly correlated to body testosterone concentration, but no statistically significant differences in sexual behavior among the lakes were found. We conclude that sexual characteristics of relevance to male reproductive capacity are altered in the Lake Apopka mosquitofish population, and we discuss the presence of chemicals with antiandrogenic effects in Lake Apopka as a possible cause of the observed alterations.
以往的实验室研究表明，具有雌激素活性和抗雄激素活性的化学物质可改变雄性食蚊鱼的若干性特征。在野外条件下是否会发生类似干扰仍有待证实。佛罗里达州的阿波普卡湖受到多种化学物质污染，其中一些具有内分泌干扰活性。从2000年12月至2001年5月，每月从阿波普卡湖以及附近的两个参照湖——橙湖和伍德拉夫湖国家野生动物保护区采集雄性食蚊鱼（霍氏食蚊鱼）。在采集期间，对选定的性特征进行了时间上的比较以及不同湖泊之间的比较。与分别从橙湖和伍德拉夫湖采集的食蚊鱼相比，阿波普卡湖的雄性食蚊鱼生殖足略短，每毫克睾丸的精子细胞平均少32%和47%。睾丸重量在春季显著增加，阿波普卡湖的食蚊鱼睾丸明显小于橙湖的，但令人惊讶的是，睾丸最小的是来自伍德拉夫湖种群的雄性食蚊鱼。阿波普卡湖种群的肝脏重量最高。睾酮和雌二醇的全身浓度随月份变化；睾酮浓度峰值出现在1月，阿波普卡湖雄性食蚊鱼的睾酮浓度显著低于橙湖。雄性求偶行为的强度与体内睾酮浓度高度相关，但未发现不同湖泊之间性行为存在统计学上的显著差异。我们得出结论，阿波普卡湖食蚊鱼种群中与雄性生殖能力相关的性特征发生了改变，并且我们讨论了阿波普卡湖中存在具有抗雄激素作用的化学物质可能是观察到的这些改变的原因。
