Legler Juliette, Dennekamp Martine, Vethaak A Dick, Brouwer Abraham, Koeman Jan H, van der Burg Bart, Murk Albertinka J
Division of Toxicology, Wageningen University, The Netherlands.
Sci Total Environ. 2002 Jul 3;293(1-3):69-83. doi: 10.1016/s0048-9697(01)01146-9.
Sediments may be the ultimate sink for persistent (xeno-)estrogenic compounds released into the aquatic environment. Sediment-associated estrogenic potency was measured with an estrogen receptor-mediated luciferase reporter gene (ER-CALUX) assay and compared with a recombinant yeast screen. The ER-CALUX assay was more sensitive to 17beta-estradiol (E2) than the recombinant yeast screen, with an EC50 of 6 pM E2 compared to 100 pM in the yeast screen. Yeast cells were unable to distinguish the anti-estrogens ICI 182,780 and (4-hydroxy)tamoxifen, which were agonistic in the yeast. Acetone-soluble fractions of hexane/acetone extracts of sediments showed higher estrogenic potency than hexane-soluble extracts in the ER-CALUX assay. Sediments obtained from industrialized areas such as the Port of Rotterdam showed the highest estrogenic potency of the 12 marine sediments tested (up to 40 pmol estradiol equivalents per gram sediment). The estrogenic activity of individual chemicals that can be found in sediments including: alkylphenol ethoxylates and carboxylates; phthalates; and pesticides, was tested. Increasing sidechain length of various nonylphenol ethoxylates resulted in decreased estrogenic activity. Of the phthalates tested, butylbenzylphthalate was the most estrogenic, though with a potency approximately 100,000 times less than E2. The organochlorine herbicides atrazine and simazine failed to induce reporter gene activity. As metabolic activation may be required to induce estrogenic activity, a metabolic transformation step was added to the ER-CALUX assay using incubation of compounds with liver microsomes obtained from PCB-treated rats. Results indicate that metabolites of E2, NP and bisphenol A were less active than the parent compounds, while metabolites of methoxychlor were more estrogenic following microsomal incubations.
沉积物可能是释放到水生环境中的持久性（外源性）雌激素化合物的最终归宿。采用雌激素受体介导的荧光素酶报告基因（ER-CALUX）分析法测定沉积物相关的雌激素活性，并与重组酵母筛选法进行比较。ER-CALUX分析法对17β-雌二醇（E2）的敏感性高于重组酵母筛选法，E2的半数有效浓度（EC50）为6 pM，而酵母筛选法中为100 pM。酵母细胞无法区分抗雌激素药物ICI 182,780和（4-羟基）他莫昔芬，而这两种药物在酵母中具有激动作用。在ER-CALUX分析法中，沉积物的己烷/丙酮提取物的丙酮可溶部分显示出比己烷可溶提取物更高的雌激素活性。从鹿特丹港等工业化地区获取的沉积物在所测试的12种海洋沉积物中显示出最高的雌激素活性（高达每克沉积物40 pmol雌二醇当量）。对沉积物中可发现的各种化学物质的雌激素活性进行了测试，这些化学物质包括：烷基酚乙氧基化物和羧酸盐；邻苯二甲酸盐；以及农药。各种壬基酚乙氧基化物侧链长度增加导致雌激素活性降低。在所测试的邻苯二甲酸盐中，丁基苄基邻苯二甲酸酯的雌激素活性最强，但其活性约比E2低100,000倍。有机氯除草剂阿特拉津和西玛津未能诱导报告基因活性。由于可能需要代谢活化来诱导雌激素活性，因此在ER-CALUX分析法中增加了一个代谢转化步骤，即将化合物与从多氯联苯处理的大鼠获得的肝微粒体一起孵育。结果表明，E2、壬基酚和双酚A的代谢产物活性低于母体化合物，而甲氧滴滴涕的代谢产物在微粒体孵育后雌激素活性更强。
