重组基因酵母法研究酞酸酯类化合物的类雌激素作用

为了检测五种酞酸酯类化合物的类雌激素活性,采用重组人雌激受体α、相关效应元件以及β-半乳糖苷酶报告基因酵母分别测定17β-雌二醇(E)2、邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二辛酯(DOP)、邻苯二甲酸丁苄酯(BBP)单独作用时诱导酶活并计算其EC50。通过各化合物与E2的EC50的比以及最大β-半乳糖苷酶活性来比较酞酸酯类化合物的类雌激素活性。五种酞酸酯类化合物的实验浓度范围为1.0×10-3~1.0×10-11 mol/L。结果表明,DEP(1×10-7~1×10-9 mol/L)、DBP(1×10-6~1×10-9 mol/L)、BBP(1×10-3~1×10-6 mol/L)具有明显的类雌激素活性,诱导的最大酶活分别为:1.515、0.832 2、1.669,而DMP和DOP并未检出明显的类雌激素活性。DEP、DBP、BBP与E2的EC50的比分别为8.85×10-2、2.54×10-2、8.82×10-6。说明DEP、DBP在低浓度就表现出类雌激素活性,而BBP在较高浓度才表现出类雌激素活性。

Comparison of Estrogenic Activity of Phthalate Esters in Vitro

A yeast-based assay was used to estimate the estrogenic potential of phthalate esters.The yeast transformants contained human-estrogen receptor α gene along with the estrogenic responsive elements upstream of β-galactosidase reporter gene.Five phthalate esters were added to yeast cultures in doses ranging from 1.0×10-3~1.0×10-11 mol/L and following incubation,the yeasts were then lysed and assayed for β–galactosidase activity.Relative potency ratios were calculated and used to compare the estrogenic activity of five phthalate esters along with β-galactosidase activity.Results showed that diethyl phthalate(DEP,1×10-7~1×10-9mol/L),dibutyl phthalate(DBP,1×10-6~1×10-9mol/L and BBP,1×10-3~1×10-6 mol/L show obviously estrogenic activity while dimethyl phthalate(DMP) and di-sec-octyl phthalate(DOP) do not.Relative potency ratios of DEP,DBP and BBP were 8.85×10-2,2.54×10-2 and 8.82×10-6 respectively,suggesting that DEP and DBP showed higher estrogenic activity than BBP.However,the maximum β-galactosidase activity induced by BBP was the same as DEP,but higher than DBP.Although the classical nuclear estrogen receptors pathway hypothesis was accepted for decades,other rapid signal transductional pathways have been found recently.The yeast-based assay was only used for primary screening,it is strongly recommended to use other ways to explore estrogenic activity for chemicals.