• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.05a
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• pp.98-98
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• 2002

• Toxicological Research
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• v.20 no.3
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• pp.205-211
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• 2004

Concern that some chemicals in our environment may affect human health by disrupt-ing normal endocrine function has prompted a research on interactions of environmental contaminants with steroid hormone receptor. Toxaphene and chlordane are among the 12 persistent organic pollutants identified by the United Nations Environment Programme as requiring urgent attention. We compared the estrogenic activity of two organochlorine pesticides, toxaphene and chlordane, at estrogen receptor a (ER$\alpha$) and estrogen receptor $\beta$ (ER$\beta$). Human hepatoma cells (HepG2) were transiently transfected with rat ER$\alpha$ or ER$\beta$ plus an estrogen-responsive complement C3-luciferase (C3-Luc) reporter gene. After transfection, cells were treated with various concentrations of toxaphene and chlordane to investigate agonism or antagonism of these chemicals. Both toxaphene and chlordane were potent agonists in HepG2 cells for ER$\alpha$. In contrast, these chemicals had a minimal agonist activity with ER$\beta$ and almost abolished 17$\beta$-estradiol-induced ER$\beta$-mediated activity. Therefore, toxaphene and chlordane behaved as an ER$\alpha$ agonist and an ER$\beta$ antagonist with estrogen-responsive reporter plasmid C3-Luc, and exposure to these organochlorine pesticides could have a crictical effect on normal endocrine function.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.581-594
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• 2017

Bisphenol A(BPA), known as a typical endocrine disruptor, has been used commercially and widely for plastics and epoxy resins. BPA-based plastic is used extensively for the production of water bottles, food containers, CDs, DVDs, and panels that can be applied in construction. Epoxy resins containing BPA are used for coatings on the insides of water pipes, food cans, and thermal papers that are used in sales receipts. As its estrogenic effects and other adverse health effects have published, BPA has been regulated in many countries, and there have been efforts made to replace BPA. Other bisphenols substitutes such as bisphenol S(BPS) and bisphenol F(BPF) have been used. Currently, BPS- and BPF-based products labeled BPA-free products have been widely consumed. Because of structural similarities with BPA, however, these alternatives also show endocrine disruption effects like BPA, and many studies on adverse health effects of these alternatives are being reported. In this review, we describe the adverse health effects of bisphenols and the current status of regulation.

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.178-181
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• 2004

Di-n-butyl phthalate (DBP) is used extensively in the plastic industry and has been known as an environmental hormone (endocrine disruptor). Present study was undertaken to examine whether DBP can induce oxidative stress in mice. In this study, oxidative stress was measured in terms of the modification of lipid peroxidation and gamma-glutamyltranspeptidase (${\gamma}-GT$) activity. The activity of ${\gamma}-GT$, the level of lipid peroxidation and serum toxicity index were measured in male ICR mice after treatment with DBP (5 g/kg, po). Administration of DBP was found to significantly increase the level of lipid peroxidation approximately 2 fold in liver. The activity of ${\gamma}-GT$ in the liver of DBP-exposed animals was also increased approximately 2.5 fold. However, DBP did not alter the parameters for hepatotoxicity and nephrotoxicity such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and creatinine. These results indicate that DBP can induce oxidative stress in mice. The ${\gamma}-GT$ activity is considered to be increased as one of the adaptive defense mechanisms to oxidative stress induced by DBP.

• Proceedings of the Korean Society of Toxicology Conference
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• 2005.05a
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• pp.184-184
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• 2005

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.1
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• pp.74-80
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• 2019

Nonylphenol is an endocrine-disrupting chemical that is the degradation product of the nonionic surfactants nonylphenol ethoxylates. To understand the contamination and behavioral characteristics of nonylphenol, we measured the nonylphenol concentrations in surface water in the lower reaches of the Suyeong River, Korea. The results were used to estimate the material balance. The target area was divided into three regions to estimate the material balance of nonylphenol. In region 1, in flux of the dissolved nonylphenol was 282.3 g/day and the nonylphenol influx in particulate suspended solids was 1,582.8 g/day. The dissolved nonylphenol outflow discharged toward region 2 was 192.5 g/day, while the adsorption to particulate suspended solids was 89.8 g/day. Within the particulate suspended solids, the outflow to region 2 was 1,250.0 g/day, while the estimated amount settling in the sediments was 422.7 g/day. The adsorption of dissolved nonylphenol to the particulate suspended solids in regions 1 and 2 was 31.8% and 54.9%, respectively. In region 3, the desorption rate was 8.8%.

• Toxicological Research
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• v.18 no.4
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• pp.331-339
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• 2002

Phenoxy compounds, 2,4-Dichlorophenol acetoxy acid (2,4-D) and 2,4-dichlorophenol (DCP), are widely used as a hormonal herbicide and intermediate for pesticide manufacturing, respectively. In order to assess the potential of these compounds as endocrine disruptors, we studied the androgenicity of them wing in vivo and in vitro androgenicity assay system. Administration of 2,4-D (50 mg/kg/day, p.o.) or DCP (100 mg/kg/day, p.o.) to rats caused an increase in the tissue weight of ventral prostate, Cowpers gland and glands penis. These increase of androgen-dependent tissues were additively potentiated when rats were simultaneously treated with low dose of testosterone (1 g/kg, s.c.). 2,4-D increased about 350% of the luciferase activity in the PC cells transiently cotransfected phAR and pMMTV-Luc at concentration of $10^{-9}$ M. In 2,4-D or DCP-treated castrated rats, testosterone 6$\beta$-hydroxylase activity was not significantly modulated even when rats were co-treated with testosterone. In vitro incubation of 2,4-D and DCP with microsomes at 50 $\mu$M inhibited testosterone 6$\beta$-hydroxylase activity about 27% and 66% in rat liver microsomes, about 44% and 54% in human liver microsomes and about 50% and 45% in recombinant CYP3A4 system, respectively. The amounts of total testosterone metabolites were reduced about 33% and 75% in rat liver microsomes, 69% and 73% in human liver microsomes and 54% and 64% in recombinant CYP3A4 by 2,4-D or DCP, respectively. Therefore, the additive androgenic effect of 2,4-D or DCP by the co-administration of the low dose of testosterone may be due to the increased plasma level of testosterone by inhibiting the cytochrome P450-mediated metabolism of testosterone. These results collectively suggested that 2,4-D and DCP may act as androgenic endocrine disrupter by binding to the androgen receptor as well as by inhibiting the metabolism of testosterone.

• Toxicological Research
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• v.21 no.4
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• pp.333-338
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• 2005

Many of thyroid hormones disrupting chemicals induce effects via interaction with thyroid hormone and retinoic acid receptors and responsive elements intrinsic in target cells. We studied thyroid hormones disrupting effects of food additives and contaminants including BHA, BHT, ethoxyquin, propionic acid, sorbic acid, benzoic acid, CPM, aflatoxin B1, cadmium chloride, genistein, TCDD, PCBs and TDBE in recombinant HeLa cells containing plasmid construct for thyroxin responsive elements. The limit of response of the recombinant cells to T3 and T4 was $1\times10^{-12}\;M$. BHA. genistein, cadmium and TBDE were interacted with thyroid receptors with dose-responsive pattern. In addition, BHA, BHT, ethoxyquin, propionic acid, benzoic acid, sorbic acid, and TBDE showed synergism while cadmium chloride antagonism for T3-induced activity. This study elucidates that recombinant HeLa cell is sensitive and high-throughput system for the detection of chemicals that induce thyroid hormonal disruption via thyroid hormone receptors and responsive elements. Also this study raised suspect of BHA. BHT, ethoxyquin, propionic acid, benzoic acid, sorbic acid, TBDE, genisteine and cadmium chloride as thyroid hormonal system disruptors.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.11b
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• pp.186-186
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• 2002

Di-n-butyl phthalate(DBP) is one of the most commonly used phthalic acid esters(PAEs) as a plasticizer, a solvent or a component in cosmetic formulations. MBP(monobutyl phthalate) is a major metabolite of DBP. Although DBP has been identified as a reproductive toxicant in several animal species and also known as a endocrine disruptor, the direct or indirect immunomodulatory effect of DBP has been little reported.(omitted)

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.160-168
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• 2021

Doublesex and mab-3 related transcription factor(dmrt) play crucial roles in sex determination and sex differentiation in vertebrates and invertebrates. Although dmrt genes have been identified in vertebrates, little is known about aquatic invertebrates. In this study, two dmrt genes, namely, Dc_dmrt93B and Dc_dmrt99B, were identified from brackish water flea, Diaphanosoma celebensis. Transcriptional changes were observed in the dmrt genes when the flea was exposed to bisphenol(BP), an endocrine disruptor. Sequence and phylogenetic analyses showed that both dmrt genes contained two conserved domains, namely, DM and DMA, closely clustered with those of Daphnia spp. Additionally, a significant increase in the Dc_dmrt99B mRNA expression level was observed upon exposure to intermediate concentrations of BP (bisphenol A>bisphenol S=bisphenol F, p<0.05), while the expression of Dc_dmrt93B mRNA was slightly modulated. These findings imply that the two dmrt genes may be involved in sex differentiation of D. celebensis. Furthermore, it was found that the ability of BP to modulate dmrt genes could affect development and reproduction. This study provides a basis for understanding the function of the dmrt genes and the molecular mode of action of BP in small crustaceans.