Metabolic activation of bisphenol A by rat liver S9 fraction
Metabolic activation of bisphenol A by rat liver S9 fraction
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DOI：
10.1093/toxsci/62.2.221
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发表时间：
2001-08-01
影响因子：
3.8
通讯作者：
Ohta, S
中科院分区：
文献类型：
--
作者：
Yoshihara, S;Makishima, M;Ohta, S
双酚A（BPA）是一种在环境中发现的众所周知的内分泌干扰化学品。为了评估摄入后BPA的雌激素活性的代谢调节，我们使用表达人雌激素受体的重组酵母和MCF-7转染的萤火虫荧光素酶质粒进行报告基因测定，研究BPA与大鼠肝脏S9组分的孵育是否导致雌激素活性的代谢活化或失活。当0.1 mM BPA与大鼠肝S9孵育1 h时，与孵育前灭活S9的对照相比，雌激素活性增加约2 - 5倍。这种代谢活化可被细胞色素P450抑制剂SKF 525-A抑制。随着孵育时间的延长，雌激素活性呈时间依赖性增加。然而，有趣的是，微粒体或胞质溶胶均未进行代谢活化。单独使用，并通过两种级分的重组恢复。活性代谢物在HPLC反相柱上的保留时间比BPA晚洗脱。双酚B和甲氧滴滴涕也通过与大鼠肝脏S9孵育而被激活，而4-叔辛基苯酚和4-壬基苯酚以及17 β-雌二醇则被代谢失活。目前的结果清楚地表明，双酚A是代谢活化的条件下，存在的条件下，只有结合大鼠肝微粒体和细胞质的雌激素活性。
Bisphenol A (BPA) is a well-known endocrine-disrupting chemical found in the environment. To assess the metabolic modulation of estrogenic activity of BPA after ingestion, we investigated whether the incubation of BPA with rat liver S9 fraction results in metabolic activation or inactivation of estrogenic activity using a recombinant yeast expressing human estrogen receptor and MCF-7 transfected firefly luciferase plasmid for a reporter assay. When 0.1 mM BPA was incubated with rat liver S9 for 1 h, the estrogenic activity was increased about two to five times compared with that of the control, in which the S9 was inactivated prior to incubation. This metabolic activation was inhibited by SKF 525-A, an inhibitor of cytochrome P450. With increasing incubation time, the estrogenic activity increased time-dependently. Interestingly, however, the metabolic activation did not proceed with either microsomes or cytosol. alone and was restored by a recombination of both fractions. The active metabolite was eluted at later retention time than that of BPA on HPLC with a reversed-phase column. Bisphenol B and methoxychlor were also activated by incubation with rat liver S9, whereas 4-tert-octylphenol and 4-non-ylphenol, as well as 17 beta -estradiol, were metabolically inactivated. The present results clearly indicate that BPA is metabolically activated in terms of estrogenicity under the conditions existing only with combined rat liver microsomes and cytosol.