Villeneuve Daniel L, Mueller Nathaniel D, Martinović Dalma, Makynen Elizabeth A, Kahl Michael D, Jensen Kathleen M, Durhan Elizabeth J, Cavallin Jenna E, Bencic David, Ankley Gerald T
U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, Minnesota 55804, USA.
Environ Health Perspect. 2009 Apr;117(4):624-31. doi: 10.1289/ehp.11891. Epub 2008 Dec 12.
Several chemicals in the environment have the potential to inhibit aromatase, an enzyme critical to estrogen synthesis.
The objective of this study was to provide a detailed characterization of molecular and biochemical responses of female fathead minnows to a model aromatase inhibitor, fadrozole (FAD).
Fish were exposed via water to 0, 3, or 30 microg FAD/L for 8 days and then held in clean water for 8 days, with samples collected at four time points during each 8-day period. We quantified ex vivo steroid production, plasma steroids, and plasma vitellogenin (Vtg) concentrations and analyzed relative transcript abundance of 10 key regulatory genes in ovaries and 3 in pituitary tissue by real-time polymerase chain reaction.
Ex vivo 17beta-estradiol (E2) production and plasma E2 and Vtg concentrations were significantly reduced after a single day of exposure to 3 microg or 30 microg FAD/L. However, plasma E2 concentrations recovered by the eighth day of exposure in the 3-microg/L group and within 1 day of cessation of exposure in the 30-microg/L group, indicating concentration- and time-dependent physiologic compensation and recovery. Concentration-dependent increases in transcripts coding for aromatase (A isoform), cytochrome P450 side-chain cleavage, steroidogenic acute regulatory protein, and follicle-stimulating hormone receptor all coincided with increased E2 production and recovery of plasma E2 concentrations.
Results of this research highlight the need to consider compensation/adaptation and recovery when developing and interpreting short-term bioassays or biomarkers or when trying to predict the effects of chemical exposures based on mode of action.
环境中的几种化学物质有可能抑制芳香化酶，这是一种对雌激素合成至关重要的酶。
本研究的目的是详细描述雌性黑头呆鱼对模型芳香化酶抑制剂法倔唑（FAD）的分子和生化反应特征。
将鱼通过水暴露于0、3或30微克FAD/升中8天，然后置于清洁水中8天，在每个8天期间的四个时间点采集样本。我们通过实时聚合酶链反应定量了体外类固醇生成、血浆类固醇和血浆卵黄蛋白原（Vtg）浓度，并分析了卵巢中10个关键调节基因和垂体组织中3个关键调节基因的相对转录本丰度。
暴露于3微克或30微克FAD/升一天后，体外17β-雌二醇（E2）生成以及血浆E2和Vtg浓度显著降低。然而，在3微克/升组中，血浆E2浓度在暴露的第八天恢复，在30微克/升组中，在停止暴露后1天内恢复，表明存在浓度和时间依赖性的生理补偿和恢复。编码芳香化酶（A亚型）、细胞色素P450侧链裂解酶、类固醇生成急性调节蛋白和促卵泡激素受体的转录本浓度依赖性增加均与E2生成增加和血浆E2浓度恢复一致。
本研究结果强调，在开发和解释短期生物测定或生物标志物时，或在试图根据作用模式预测化学物质暴露的影响时，需要考虑补偿/适应和恢复情况。
