The Study Of The Endocrine Disruptor Activity To The Seven Environmental Estrogens By Yeast Estrogens Screen

This paper use yeast estrogen screen to study the estrogenic effect of individual andcombination on 17β-estradiol (E2), 17α-ethynylestradiol (EE2), 4-n-Nonylphenol (4-NP),Bisphenol A (BPA), Pentachlorophenol (PCP), o,p'-Dichlorodiphenyltrichloroethane(o,p'-DDT), and p,p'-Dichlorodiphenyl- trichloroethane (p,p'-DDT). The results showedthat these seven chemicals had the estrogenic activities in the definite range ofconcentration with an evident "S" dose-response relationship curve. With the concentrationof chemicals increasing, the β-galactosidase activity also increased, which showed theconcentration that causes 50% efficiency (EC50) as following: E2: at the concentration of 0.05~100nmol/L, it can lead to the increasing of theβ-galactosidase activity, the minimum β-gal. activity was 0.08, the maximum β-gal. activitywas 0.88, EC50 value was 1.06nM, and correlation coefficient was 0.9985. EE2: at the concentration of 0.02~100nmol/L, it can lead to the increasing of theβ-galactosidase activity, the minimum β-gal. activity was 0.03, the maximum β-gal. activitywas 0.35, EC50 value was 1.07nM, and correlation coefficient was 0.999. 4-NP: at the concentration of 0.02~10μmol/L, it can lead to the increasing of theβ-galactosidase activity, the minimum β-gal. activity was -0.23, the maximum β-gal.activity was 0.25, EC50 value was 0.42μM, and correlation coefficient was 0.9973. BPA: at the concentration of 0.25~50μmol/L, it can lead to the increasing of theβ-galactosidase activity, the minimum β-gal. activity was -0.01, the maximum β-gal.activity was 0.24, EC50 value was 2.04μM, and correlation coefficient was 0.9964. PCP: at the concentration of 0.01~5μmol/L mmol/L, it can lead to the increasing ofthe β-galactosidase activity, the minimum β-gal. activity was 0.02, the maximum β-gal.activity was 0.33, EC50 value was 0.48μM, and correlation coefficient was 0.9985. o,p'-DDT: at the concentration of 0.05~20μmol/L, it can lead to the increasing of theβ-galactosidase activity, the minimum β-gal. activity was -0.06, the maximum β-gal.activity was 0.53, EC50 value was 1.48μM, and correlation coefficient was 0.9983. p,p'-DDT: at the concentration of 0.1~1000μmol/L, it can lead to the increasing of theβ-galactosidase activity, the minimum β-gal. activity was 0.001, the maximum β-gal.activity was 0.42, EC50 value was 8.01μM, and correlation coefficient was 0.9976. The binary combinations of 4-NP, BPA, PCP, o,p'-DDT and p,p'-DDT were mixed atthe toxic unit ratio of 1:1, 1:4 and 4:1. The chemicals of 4-NP, BPA, PCP and o,p'-DDTwere mixed of three sorts at the toxic unit ratio of 1:1:1. Toxic unit and additive index wereadopted to evaluate combination toxicity. The results revealed that the combination toxicityof NP+BPA and BPA+o,p'-DDT was synergistic effect at all the toxic unit ratio;NP+o,p'-DDT was synergistic effect at the ratio of 1:1 and 1:4, but antagonistic effect wasobserved at the ratio of 4:1; other binary combinations all showed antagonistic effect.NP+BPA+o,p'-DDT exhibited synergistic effect at the ratio of 1:1:1, and antagonistic effectwere found in the mixtures of NP+BPA+PCP, NP+PCP+o,p'-DDT and BPA+PCP+o,p'-DDT.