Androgens and estrogens often co-exist in aquatic environments and pose potential risks to fish populations. However, little is known about the endocrine disrupting effects of the mixture of androgens and estrogens in fish. In this study, transcriptional level of target genes related to the hypothalamic-pituitary-gonadal-liver (HPGL) axis, sex hormone level, VTG protein concentration, histology and secondary sex characteristic were assessed in the ovaries and livers of adult female western mosquitofish (Gambusia affinis) exposed to 17β-estradiol (E2), testosterone (T), and mixtures of E2 and T for 91 days. The results showed that the transcriptional expression of cytochrome P450, family 19, subfamily A, polypeptide 1a (Cyp19a1a) was suppressed in the 200 ng/L T treatment and the 50 ng/L E2 + 200 ng/L T treatment in the ovaries. Steroidogenic acute regulatory protein (Star) and Cyp11a1 showed a similar expression pattern in the T treatment to its corresponding T + E2 mixtures. In the ovaries, the concentrations of 17β-estradiol and testosterone were decreased in most treatments compared with the solvent control. VTG protein was induced in all steroid treatment. However, exposure to T or E2 + T mixture did not cause the abnormal cells of the ovaries and livers and an extension of the anal fins in female G. affinis. This study demonstrates that chronic exposure to E2, T and their mixtures affects the transcripts of genes in the HPGL axis, steroid hormone level and VTG protein concentration in the ovaries and livers, but fails to cause the histopathological effect of the ovaries and livers and alter the morphology of the anal fins in G. affinis.

雄激素和雌激素通常在水生环境中共存，对鱼类种群构成潜在风险。然而，关于鱼类中雄激素和雌激素混合物的内分泌干扰作用知之甚少。在这项研究中，评估了成年雌性西方蚊鱼卵巢和肝脏中与下丘脑-垂体-性腺-肝（HPGL）轴，性激素水平，VTG蛋白浓度，组织学和第二性征相关的靶基因的转录水平（Gambusia affinis）暴露于17β-雌二醇（E2），睾丸激素（T）以及E2和T的混合物中91天。结果表明，细胞色素P450家族19亚家族A多肽1a（Cyp19a1a）的转录表达）在200 ng / LT处理和50 ng / L E2 + 200 ng / LT处理中在卵巢中被抑制。类固醇激素急性调节蛋白（Star）和Cyp11a1在T处理中与其相应的T + E2混合物表现出相似的表达模式。在卵巢中，与溶剂对照组相比，大多数治疗中17β-雌二醇和睾丸激素的浓度均降低。VTG蛋白在所有类固醇治疗中均被诱导。但是，暴露于T或E2 + T混合物中并不会引起卵巢和肝脏的异常细胞以及雌性G. affinis的肛门鳍延伸。。这项研究表明，长期暴露于E2，T及其混合物会影响卵巢和肝脏中HPGL轴基因的转录本，类固醇激素水平和VTG蛋白浓度，但不会引起卵巢和肝脏的组织病理学效应并改变柏（G. affinis）肛门鳍的形态。