• Toxicological Research
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• v.16 no.2
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• pp.141-146
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• 2000

Phthalate esters are used extensively as a plasticizer in the manufacture of plastic products such as PVC bags and medical devices. Recently, phthalate esters have been shown to induce endocrine system mediated responses. However. only a Jew studies have been conducted for estrogenic activity of phthalate esters. In this study estrogenic activities of seven phthalate esters. butyl benzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), di-n-butylphthalate (DBP), diethylphthalate (DEP), di-n-pentylphthalate (DPP), di-n-propylphthalate (DPrP) and dicyclohexylphthalate (DCHP), were examined in vitro using E-screen assay and competitive binding assay. From the E-screen assay, BBP. DEHP. DBP and DEP showed weak estrogenic activity at the concentration of 5 $\mu\textrm{M}$. The relative proliferative effect (RPE) and the relative proliferative potency (RPP) were 50~70% and 0.01%. respectively, when compared with 500 pM of 17$\beta$-estradiol (E2). In competitive binding assay with the rat uterine estrogen receptor (ER), BBP and DEP showed weak binding potency ［(l/$10^4$~1/$10^5$ of E2］ while DEHP and DBP scarcely bound to ER. These results suggest that some phthalate esters have weak estrogenic activities in vitro.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.591-597
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• 2004

In this study, sixty chemicals including 47 pesticides were screened for estrogenic activity using E-screen assay. MCF-7 cell, used in E-screen assay, is known to be proliferated by addition of estrogenic chemicals. Eight of the measured pesticides showed estrogenic activity at the concentration range of 100-10,000nM. Their relative proliferative effect (RPE) and the relative proliferative potency (RPP) were 20-65% and 0.01-1.0%, respectively, when compared with 1.0nM of $\beta-Estradiol-17-acetate(E_{2}).$ DDVP and diazinone showed most strong estrogenic potency(RPP; 1.0%) and effect(RPE; 65%) of the eight pesticides. These results are in agreement with estrogenic activity of bisphenol A is known as a positive endocrine disrupter. Also, in this study, paraquat, DDVP, 4-chloro-3-methylphenol, 2,4,6-trichlorophenol and diazinon of the measured pesticides are estimated to estrogenic chemical.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.964-969
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• 2000

Di-(2-ethylhexyl) adipate(DEHA) has been used extensively as a plasticizer in the manufacture of plastic products such as PVC films. Though, phthalate esters plasticizers have been known to induce endocrine system-mediated responses, few studies have been conducted for the screening of estrogenic activity of DEHA, an adipate plasticizer. This study was initiated to evaluate the estrogenic activity of DEHA by in vitro E-screen assay and in vivo uterotrophic assay. MCF-7 human breast cancer cells were treated with $DEHA(5{\times}10^{-9}{\sim}5{\times}10^{-4}\;M)$, for 144 hr, and cell proliferation was determined by sulforhodamine B(SRB) assay. DEHA dissolved in corn oil was administered subcutaneously to ovariectomized(OVX) female Sprague-Dawley rats at dosage levels of 0, 2, 20 and 200 mg/kg/day for three consecutive days. Rats were sacrificed 24 hr after final treatment and vagina and uterus(wet and blotted) weights were obtained. E-screen assayed DEHA did not generate cell proliferation at treated concentrations$(5{\times}10^{-9}{\sim}5{\times}10^{-4}\;M)$, whereas 17 ${\beta}-estradiol$(E2), the positive control, induced cell proliferation at low concentrations$(5{\times}10^{-14}{\sim}5{\times}10^{-9}\;M)$. In the uterotrophic assay, DEHA did not change vagina and uterus(wet and blotted) weights at dosage levels up to 200 mg/kg/day treatment. These results demonstrated that DEHA did not exhibit the estrogenic activity as determined by in vitro E-screen assay and in vivo uterotrophic assay.

• YAKHAK HOEJI
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• v.44 no.5
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• pp.416-423
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• 2000

There is a growing concern that a wide variety of chemicals released into the environment can disrupt the endocrine system of fish, wildlife and humans. Endocrine disrupting chemicals (EDCs) include pesticides such as DDT lindane and atrazine, the food packaging chemicals, phthalates and bisphenol A, alkylphenol ethoxylate detergents and the chemical industry by-products, dioxins. Xenoestrogens in the environment have been argued about health risk, because of estrogen mimetic chemicals are exposed only small amounts to human. A number of in vivo and in vitro assays are now in use to assess the activity of xenoestrogens in the environment. A human breast cancer cell line (MCF-7) was used to develop in vitro screening assay for the detection of xenoestrogenic environmental pollutants. The E-SCREEN (MCF7-BUS) assay is proposed as a reliable, easy and rapid-to-perform method. To optimize and validate this method before it can be used routinely, several phenol compounds and pesticides suspected to be estrogenic were tested using I-SCREEN assay. The results showed that this method is a valuable tool for screening potential estrogen-mimicking environmental pollutants and quantitative determination of estrogeniciy.

• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.293-299
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• 2000

Many methods have been developed for screening chemicals with hormonal activity. Using recombinant yeasts expressing either human estrogen receptor [Saccharomyces cerevisiae ER + LYS 8127 (YER)] or androgen receptor [S. cerevisiae AR + 8320 (YAR)], we evaluated the hormonal activities of several chemicals by induction of ${\beta}-galactosidase$ activity. The chemicals were $17{\beta}-estradiol$ (E2), testosterone (T), ${\rho}-nonylphenol$ (NP), bisphenol A (BPA), genistein (GEN), 2-bromopropane (2-BP), dibutyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and butylparaben (BP). To assess the estrogenicity of NP, the result of the in vitro recombinant yeast assay was compared with an E-screen assay using MCF-7 human breast cancer cells and an uterotrophid assay using ovariectomized mice. In the YER yeast cells, E2, NP, BPA, GEN, and BP exhibited estrogenicity in a doseresponse manner, while TCDD did not. All the chemicals tested, except T, did not show androgenicity in the YAR yeast cell. The sensitivity of the yeast (YER) assay system to the estrogenic effect of NP was similar to that of the E-screen assay. NP was also estrogenic in the uterotrophic assay. However, in terms of convenience and costs, the yeast assay was superior to the E-screen assay or uterotrophic assay. These results suggest that the recombinant yeast assay can be used as a rapid tool for detecting chemicals with hormonal activities.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.697-703
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• 2006

Endocrine disruptors were measured with GC/MS in effluents discharged from sewage treatment processes in pilot scale for the purpose of water reuse. From that analysis, we compared the removal rate of them by treatment processes. Nonylphenol was mainly detected in effluents and high concentration from 0.36 to 0.94 ${\mu}g/L$. $17{\beta}$-estradiol(E2) and $17{\alpha}$-ethynylestradiol(EE2) were detected as below the limit of detection in effluent. Endocrine disruptors were removed effectively in the range from 50 to 100% by treatment process. EC50 value($9.0{\times}10^{-3}$ M) of $17{\beta}$-estradiol(E2) by dose response curve of E-screen assay has higher than that of bisphenol A($2.736{\times}10^{-5}M$) and p-octylphenol($9.760{\times}10^{-6}$ M). These results showed that alkylphenols have lower relative estrogen potency than other estrogens such as $17{\beta}$-estradiol(E2). Calculated estrogenic activity(ng-EEQ/L) was 2 times higher than measured total estrogenic activity which estimated by E-screen assay. Moreover estrogenic activity of effluent by treatment process showed very low as below 1 ng-EEQ/L.

• Molecular & Cellular Toxicology
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• v.2 no.2
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• pp.106-113
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• 2006

Phthalate analogues are a plasticizer and solvent used in industry. Phthalates were classified in the category of "suspected" endocrine disruptors. The purpose of our study was to screen and elucidate the endocrine disrupting activity of seven phthalate analogues. E-screen assay was performed in MCF-7 human breast cancer cells with seven phthalate analogues. In this cell proliferation assay, benzyl butyl phthalate (BBP) and dibutyl phthalate (DBP) showed high estrogenic activity. Their relative proliferation efficiencies (RPE) were 109 and 106%, respectively. In vitro estrogen receptor (ER) binding assay, BBP, di-n-octyl phthalate (DOP) and dinonyl phthalate (DNP) showed weak relative binding affinity (RBA: 0.02%) compared to $17{\beta}-estradiol\;(E2)$ (RBA: 100%). In uterotrophic assay, E2 produced a significant increase, whereas four tested phthalate analogues had potential estrogenic effects in vitro did not increased in uterus weight in immature rats. From these results, we demonstrated that phthalate analogues exhibit weak estrogenic activity in vitro assays at high concentrations. Although phthalates induced an increase in MCF-7 cell proliferation by an estrogenic effect, they could not induce a uterus weight increase in vivo. From these, we may suggest that these phthalate analogues are easily metabolized to inactive forms in vivo. Further investigation in other in vitro and in vivo experimental systems might be required.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2000.12a
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• pp.55-55
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• 2000

• Toxicological Research
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• v.16 no.4
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• pp.285-291
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• 2000

So far, investigation of environmental pollution has been achieved in field study. This remains the most exhaustive approach, current dimensions of environmental researches and their inherent complexity require that relatively inexpensive and simple laboratory procedures are developed to make possible the screening of large numbers of sites and samples. At this point. microbioassay has been high-lighted. The purpose of this study is to evaluate the water pollution using microbioassay. Two microbioassay methods were optimized and validated for the sensitive and quantitative determination of total toxic effects in the water. EROD(Ethoxyresorufin-O-deethylase) microbioassay was focused to detect PARs, PCBs and dioxinlike components in the water and E-screen assay to xenoestrogens. The EROD microbioassay was executed in rat hepatoma cell line, H4IIE and E-screen assay in MCF7-BUS cell line. Kumho river was selected for this study. 5ι of river water was extracted using combined solid-phase extraction in static adsorption mode with soxhlet extraction. Pollutants adsorbed to the XAD-4 resin were recovered by elution with ethyl acetate and methylene chloride (1 : 9). Toxic effects of extracts were determined by EROD-microbioassay and E-screen assay. EROD activities of water samples were 7.24-72.24 ng/ι MEQ. The estrogenic effect of various water samples is quantitatively evaluated by EEQ. The EEQ of samples range from 0.05 to 6.07 ng-EEQ/ι. These results suggested that Kumho river was highly polluted with organic toxic chemicals.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.2
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• pp.86-92
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• 2007

In this study, we tried to quantitatively study the distribution of estrogenic activity in sediment from Gwangyang Bay by E-screen assay. Besides, we compared the estrogenic activity and the concentration of chemical pollutants. The highest estrogenic activity was recorded at the stations(GY6 and GY8) close to industrial complex and the river mouth of Seomjin. These results obtained from the E-screen assay similar to those of simultaneous analytical detection of 310 chemicals. In particular, GY6 and GY8 sites are confirmed as the full agonist sites because of their RPE values were over 90% having strong estrogenic effect. Also, their EEQ(Estradiol Equivalency Quantity) values are 35.6 ng/g and 14.6 ng/g, low than that of other sites, and these results suggests that have relatively high estrogenic efficiency in Gwangyang Bay. From these results, we can estimate that the stations close to industrial complex and the river mouth of Seomjin are major sources of endocrine disrupter in Gwangyang Bay. On the other hand, when we tried to compare the endocrine disrupter activity and $COD_{Mn}$ value, that is not correlated.