Folmar Leroy C, Hemmer Michael J, Denslow Nancy D, Kroll Kevin, Chen Jian, Cheek Ann, Richman Harold, Meredith Hillary, Grau E Gordon
US Environmental Protection Agency, 1 Sabine Island Drive, Gulf Breeze, FL 32561, USA.
Aquat Toxicol. 2002 Oct 2;60(1-2):101-10. doi: 10.1016/s0166-445x(01)00276-4.
Five natural, pharmaceutical, or xenobiotic chemicals [17beta-estradiol (E2), ethynylestradiol (EE2), diethystilbestrol (DES), methoxychlor (MXC), nonylphenol (NP)] were tested in two in vitro assays [yeast estrogen screen (YES), MCF-7 breast tumor cell proliferation (E-Screen)], and compared with previously reported results from two in vivo male sheepshead minnow vitellogenin (VTG) production studies. The purpose of this investigation was to determine how accurately the two in vitro assays predicted responses observed in live animals. EC50 values for all five chemicals were approximately one order of magnitude less sensitive in the YES assay than in the MCF-7 assay. Based on the EC50 values, DES was 1.1 (YES) to 2.5 (MCF-7) times more potent in these receptor binding assays than was E2, while EE2 was slightly less potent than E2 in the YES assay (0.7) and nearly twice as potent (1.9) as E2 in the MCF-7 assay. EE2 and DES were of approximately equal potency in the 13-day sheepshead minnow VTG production bioassay. Both MXC and NP were 10(7) times less potent than E2 in the YES assay, MXC was 10(5) times less estrogenic than E2 in the MCF-7 assay, while both were approximately 100 times less potent than E2 in the live animal bioassay. The in vitro tests were substantially less sensitive (at least 1000 times) than the sheepshead minnow VTG assay for estimating estrogenic potency of the two xenobiotic chemicals, which suggests that in vitro-based, large-scale screening programs could potentially result in many false negative evaluations.
在两项体外试验[酵母雌激素筛选试验（YES）、MCF-7乳腺癌细胞增殖试验（E-Screen）]中对五种天然、药物或外源性化学物质[17β-雌二醇（E2）、乙炔雌二醇（EE2）、己烯雌酚（DES）、甲氧滴滴涕（MXC）、壬基酚（NP）]进行了测试，并与之前两项关于雄性红鼓鱼卵黄蛋白原（VTG）生成的体内研究报告结果进行了比较。本研究的目的是确定这两项体外试验对活体动物中观察到的反应的预测准确性。在YES试验中，所有五种化学物质的半数有效浓度（EC50）值的敏感性比在MCF-7试验中低约一个数量级。基于EC50值，在这些受体结合试验中，DES的效力比E2高1.1倍（YES试验）至2.5倍（MCF-7试验），而EE2在YES试验中的效力略低于E2（0.7），在MCF-7试验中的效力几乎是E2的两倍（1.9）。在为期13天的红鼓鱼VTG生成生物试验中，EE2和DES的效力大致相当。在YES试验中，MXC和NP的效力均比E2低10^7倍，在MCF-7试验中，MXC的雌激素活性比E2低10^5倍，而在活体动物生物试验中，二者的效力均比E2低约100倍。在估计两种外源性化学物质的雌激素效力方面，体外试验的敏感性比红鼓鱼VTG试验低得多（至少1000倍），这表明基于体外试验的大规模筛选计划可能会导致许多假阴性评估。
