RMIT University, Bundoora West Campus, School of Applied Sciences, Bundoora, Victoria 3083, Australia.
Comp Biochem Physiol C Toxicol Pharmacol. 2013 Mar;157(2):162-71. doi: 10.1016/j.cbpc.2012.11.004. Epub 2012 Nov 22.
This study investigated the influence of two endocrine disrupting chemicals (EDCs)-an exogenous oestrogen 17β-estradiol (E2) and the oestrogen mimic 4-n-nonylphenol (NP) on the expression of aromatase transcripts in both sexes of adult Murray river rainbowfish. Reproductively active mature fish were exposed to 1, 3, and 5 μg/L E2 or 100 and 500μg/L NP for 24, 48, 72 and 96 h. The results show a significant reduction in the expression of cyp19a1a isoform in ovarian tissues with complete inhibition at the higher concentrations (3 and 5 μg/L E2; 500μg/L NP between 24 and 72 h) and at all concentrations after 96 h. There was no expression of the cyp19a1a isoform in female brain, male brain or testes in any treatment. E2 significantly increased expression of cyp19a1b in female brain except at 5 μg/L after 24h exposure. In male brain tissue E2 exposure decreased cyp19a1b expression except at 1 and 5 μg/L at 24h. NP significantly upregulated cyp19a1b in the female brain (except with 500 μg/L at 72 h) and in testes tissues. NP downregulated expression of cyp19a1b in the male brain tissue. Collectively, these observations support the hypothesis that the expression of cyp19a1b is regulated via both positive and negative feedback mechanisms, with differential modulation based on the type and concentration of the exposed oestrogens, duration of exposure, fish tissue and gender of the fish. The results also imply that exogenous oestrogens can have a disruptive effect on the steroidogenic pathway and may lead to effects on sex differentiation, sexual behaviour and reproductive cycles in this fish.
本研究调查了两种内分泌干扰化学物质（EDCs）——外源性雌激素 17β-雌二醇（E2）和雌激素类似物 4-壬基酚（NP）对成年墨累河彩虹鱼雌雄两性芳香酶转录本表达的影响。生殖活跃的成熟鱼类暴露于 1、3 和 5μg/L E2 或 100 和 500μg/L NP 24、48、72 和 96 小时。结果表明，cyp19a1a 同工型在卵巢组织中的表达显著降低，在较高浓度（3 和 5μg/L E2；500μg/L NP 在 24 至 72 小时之间）和 96 小时后所有浓度下完全抑制。在任何处理中，雌性脑、雄性脑或睾丸均未表达 cyp19a1a 同工型。E2 显著增加了雌性脑中 cyp19a1b 的表达，除了在 24 小时暴露于 5μg/L 时。在雄性脑组织中，E2 暴露除了在 24 小时时的 1 和 5μg/L 外，降低了 cyp19a1b 的表达。NP 显著上调了雌性脑（72 小时时除外 500μg/L）和睾丸组织中 cyp19a1b 的表达。NP 下调了雄性脑组织中 cyp19a1b 的表达。总的来说，这些观察结果支持这样的假设，即 cyp19a1b 的表达是通过正反馈和负反馈机制调节的，基于暴露的雌激素的类型和浓度、暴露时间、鱼类组织和鱼类的性别，有不同的调节方式。结果还表明，外源性雌激素可能对类固醇生成途径产生干扰作用，并可能导致这种鱼类的性别分化、性行为和生殖周期产生影响。
