Steroid hormones, including estrone (E1), androstadienedione (ADD), and androstenedione (AED), are prevalent in aquatic ecosystems and pose ecological risks due to their disruptive influence on fish populations. However, little consideration has been given to the endocrine disrupting effects of fish exposed to complex mixtures of hormones in the real world. In this study, adult female western mosquitofish (Gambusia affinis) were exposed to two concentrations of E1 (100 ng/L for E1L and 5,000 ng/L for E1H), ADD (100 ng/L for ADDL and 10,000 ng/L for ADDH), and AED (100 ng/L for AEDL and 10,000 ng/L for AEDH) as well as four binary mixture treatments (ADDL+E1L, ADDH+E1H, AEDL+E1L, and AEDH+E1H). After 42 d, their basic physiological parameters, secondary sex characteristics, gonadal health, embryo numbers, and HPG axis-related gene expression were evaluated. Results showed that the P/D ratio of hemal spines in AEDH+E1H exhibited a pronounced reduction, approximately half that of E1H. Moreover, the number of embryos in ADDH+E1H and AEDH+E1H was reduced by approximately 3-fold compared to E1H. Correspondingly, G. affinis exposure to ADDH+E1H and AEDH+E1H increased the proportion of degenerated oocytes. Exposure to combined treatments led to significant changes in the transcription of HPG axis-related genes in fish and displayed a certain degree of interaction. Furthermore, cluster heatmap analysis of target genes demonstrated that ADD+E1 and AED+E1 (both high and low concentrations) were far apart from ADD, AED and E1. Collectively, these observations imply the presence of antagonistic interactions in combined treatments, and the negative impact on the growth, maturation, and endocrine system of G. affinis varies accordingly.

中文翻译：

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类固醇激素及其混合物对西部蚊鱼 （Gambusia affinis） 的影响


类固醇激素，包括雌酮 （E1）、雄二烯二酮 （ADD） 和雄烯二酮 （AED），在水生生态系统中普遍存在，由于它们对鱼类种群的破坏性影响而构成生态风险。然而，在现实世界中，很少考虑暴露于复杂激素混合物的鱼的内分泌干扰作用。在这项研究中，成年雌性西部蚊鱼 （Gambusia affinis） 暴露于两种浓度的 E1 （E1L 为 100 ng/L，E1H 为 5,000 ng/L）、ADD（ADDL 为 100 ng/L，ADDH 为 10,000 ng/L）和 AED（AEDL 为 100 ng/L，AEDH 为 10,000 ng/L）以及四种二元混合物处理（ADDL+E1L、 ADDH+E1H、AEDL+E1L 和 AEDH+E1H）。42 d 后，评估其基本生理参数、第二性征、性腺健康状况、胚胎数量和 HPG 轴相关基因表达。结果显示，AEDH+E1H 中半棘的 P/D 比值明显降低，约为 E1H 的一半。此外，与 E1H 相比，ADDH+E1H 和 AEDH+E1H 中的胚胎数量减少了约 3 倍。相应地，G. affinis 暴露于 ADDH+E1H 和 AEDH+E1H 增加了退化卵母细胞的比例。暴露于联合处理导致鱼类 HPG 轴相关基因转录发生显着变化，并表现出一定程度的相互作用。此外，靶基因的聚类热图分析表明，ADD+E1 和 AED+E1 （高浓度和低浓度） 与 ADD、AED 和 E1 相差甚远。总的来说，这些观察结果表明联合治疗中存在拮抗相互作用，并且对 G. affinis 的生长、成熟和内分泌系统的负面影响也相应地不同。