• Journal of Environmental Health Sciences
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• v.29 no.2
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• pp.7-15
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• 2003

Di-2-ethylhexyl phthalate (DEHP), is a widely used plasticizer known to be a suspected endocrine disrupter, but its exact effects on aquatic organisms are not yet known. When Japanese medaka (Oryzias latipes) were exposed from the time of hatching to 3 months of age to an aqueous DEHP solution at nominal concentrations of 1, 10, and 50 $\mu\textrm{g}$/l, DEHP treated female fish showed distinct reproductive effect. And the midge (Chironomus riparius.). an aquatic invertebrate, was exposed to DEHP to evaluate the effects on reproductive processes via sediment toxicity. The test endpoints included emergence, sex ratio, fecundity, and the viability of F1 offspring egg ropes. The result implied that the normal developmental and/or reproductive processes in C. riparius had been disrupted when exposed to DEHP, the effect also being displayed in the next generation. In summary, DEHP hinders the development of reproductive organs in the female Japanese medaka and C. riparius.

• Journal of Microbiology and Biotechnology
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• v.33 no.10
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• pp.1351-1360
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• 2023

Endocrine-disrupting chemicals (EDCs) are compounds that disturb hormonal homeostasis by binding to receptors. EDCs are metabolized through hepatic enzymes, causing altered transcriptional activities of hormone receptors, and thus necessitating the exploration of the potential endocrine-disrupting activities of EDC-derived metabolites. Accordingly, we have developed an integrative workflow for evaluating the post-metabolic activity of potential hazardous compounds. The system facilitates the identification of metabolites that exert hormonal disruption through the integrative application of an MS/MS similarity network and predictive biotransformation based on known hepatic enzymatic reactions. As proof-of-concept, the transcriptional activities of 13 chemicals were evaluated by applying the in vitro metabolic module (S9 fraction). Identified among the tested chemicals were three thyroid hormone receptor (THR) agonistic compounds that showed increased transcriptional activities after phase I+II reactions (T3, 309.1 ± 17.3%; DITPA, 30.7 ± 1.8%; GC-1, 160.6 ± 8.6% to the corresponding parents). The metabolic profiles of these three compounds showed common biotransformation patterns, particularly in the phase II reactions (glucuronide conjugation, sulfation, GSH conjugation, and amino acid conjugation). Data-dependent exploration based on molecular network analysis of T3 profiles revealed that lipids and lipid-like molecules were the most enriched biotransformants. The subsequent subnetwork analysis proposed 14 additional features, including T4 in addition to 9 metabolized compounds that were annotated by prediction system based on possible hepatic enzymatic reaction. The other 10 THR agonistic negative compounds showed unique biotransformation patterns according to structural commonality, which corresponded to previous in vivo studies. Our evaluation system demonstrated highly predictive and accurate performance in determining the potential thyroid-disrupting activity of EDC-derived metabolites and for proposing novel biotransformants.

• Development and Reproduction
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• v.27 no.4
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• pp.185-193
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• 2023

Although increasing evidence of cause-and-effect relationship between BPA exposure and female reproductive disorders have been suggested through many studies, the precise biochemical and molecular mechanism(s) by which BPA interferes with steroidogenesis in the ovarian cells still remain unclear. Therefore, the purpose of this study was to discover the steroidogenic biomarker(s) associated with BPA treatment in human granulosa cell line, KGN. In this study, our results obtained via the analysis of steroidogenesis-related protein expression in KGN cells using quantitative polymerase chain reaction (qPCR) and western blot analyses revealed that the expression levels of steroidogenic acute regulatory (StAR) and aromatase decreased considerably and gradually after BPA treatment in a dose-dependent manner under BPA treatment. Further, remarkable decreases in their expression levels at the cellular levels were also confirmed via immunocytochemistry, and subsequent StAR and aromatase mRNA expression levels showed profiles similar to those observed for their proteins, i.e., both StAR and aromatase mRNA expression levels were significantly decreased under BPA treatment at concentrations ≥0.1 μM. We observed that follicle stimulating hormone upregulated StAR and aromatase protein expression levels; however, this effect was suppressed in the presence of BPA. Regarding the steroidogenic effects of BPA on KGN cells, controversies remain regarding the ultimate outcomes. Nevertheless, we believe that the results here presented imply that KGN cells have a good cellular and steroidogenic machinery for evaluating endocrine disruption. Therefore, StAR and aromatase could be stable and sensitive biomarkers in KGN cells for the cellular screening of the potential risk posed by exogenous and environmental chemicals to female reproductive (endocrine) function.

• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.96-101
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• 2004

The effects of the ecdysteroid agonist tebufenozide on the larvae of Chironomus flaviplumus and Chironomus riparius were tested in the laboratory. Employing a static exposure setup, chironomids were subjected to various tebufenozide concentrations. In the most treatments it reach-ed a statistically significant difference from the control condition. As the concentration of tebufenozide was increased, a relatively larger proportion of the observed mortality was associated with the metamorphosis and molting process. The larval mortality of C. riparius was high in C. flaviplumus during over 30 ${\mu}g\;L^{-1}$ treatments. In terms of development, the effects of tebufenozide were delayed growth stage in relatively lower concentration such as 10 ${\mu}g\;L^{-1}$ tebufenozide treatments. The rates of succeed adult through the molting process were various in treated concentrations or/and the species.

• Journal of Environmental Science International
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• v.21 no.7
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• pp.845-853
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• 2012

Diethyl phthalate (DEP) is widely spread in the natural environment as an endocrine disruption chemicals (EDs). Therefore, in this study, ultrasound (US) and ultraviolet (UVC), including various applied power density (10-40 W/L), UV wavelengths (365 nm, 254 nm and 185 nm) and frequencies (283 kHz, 935 kHz) were applied to a DEP contaminated solution. The pseudo-first order degradation rate constants were in the order of $10^{-1}$ to $10^{-4}\;min^{-1}$ depending on the processes. Photolytic and sonophotolytic DEP degradation rate also were high at shortest UV wavelength (VUV) due to the higher energy of photons, higher molar absorption coefficient of DEP and increased hydroxyl radical generation from homolysis of water. Sonolytic DEP degradation rate increased with increase of applied input power and the dominant reaction mechanism of DEP in sonolysis was estimated as hydroxyl radical reaction by the addition of t-BuOH, which is a common hydroxyl radical scavenger. Moreover, synergistic effect of were also observed for sonophotolytic degradation with various UV irradiation.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.561-570
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• 2004

This study was carried out to survey the pollution of nonylphenol (NP) in surface sediments around Gwangyang bay and Yeosu sound. NP was suspected chemicals as endocrine disruption. Gwangyang bay is located on the mid south coast of Korea. It is a semi-closed bay which Yeosu petrochemical industrial complex, POSCO (Pohang Steel Company) and Gwangyang container harbor are there. The surface sediments were collected at 15 stations with gravity corer at October, 1999, February, May and August, 2000. Also, the stream and intertidal sediment were collected at 5 sites at August, 2000. Concentrations of NP in surface sediments were in the range of 6.89 to 202.70 ng/g dry wt.. Seasonal range (mean value) of NP is 13.98 to 30.48 (23.46) ng/g dry wt. at October, 10.35 to 54.91 (28.10) ng/g dry wt. at February, 29.05 to 202.70 (82.32) ng/g dry wt. at May and 6.98 to 83.40 (25.37) ng/g dry wt. at August. NP was seasonally fluctuated, and the highest mean value and range was detected at May, 2000. NP was highly distributed in the inner part of Gwangyang bay than Yeosu sound. Concentrations of NP in stream and intertidal sediments showed the highest value in downstream near Yeosu petrochemical industrial complex and Yondung stream. It suggests that the source of NP is industrial wastewater and municipal sewage.

• The Korean Journal of Community Living Science
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• v.23 no.4
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• pp.411-418
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• 2012

Phthalates and di-2-ethylhexyladipate are both widely used as industrial chemicals and exposure high levels over long periods of time can cause toxicity, estrogenic responses and endocrine disruption properties in both humans and animals. So far, their global monitoring in environmental matrices has been performed continuously. A developed method, including modified SPEED'98 (Japan Environment Agency) and USEPA was established for simple and rapid determination of phthalates and di-2-ethylhexyladipate in various matrices. This method was applied to explore the distribution levels in domestic environmental media such as water, soil and sediment. Eight phthalates (DEP(di-ethyl), DEHP(di-[2-ethyl-hexyl]), DprP (di-propyl), DBP(di-n-butyl), DPP(di-n-pentyl), DHP(di-n-hexyl), DCHP(di-cyclohexyl), BBP(butyl benzyl) and Adipate (di-2-ethylhexyl adipate) were investigated by seasonal sampling(spring, autumn) at 24 domestic sites. Phthalates and adipate were not detected in water samples and DEP, DBP, and DEHP were mainly detected in soil and sediment samples. The concentrations of DEP and DBP excluding DEHP in spring were higher in soil than those of sediment. Total concentrations of phthalates were significantly decreased in autumn for both soil and sediment.

• Korean Journal of Environmental Biology
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• v.30 no.4
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• pp.287-306
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• 2012

Amphibian population declines globally. Environmental contamination by heavy metals has been suspected to the one of the reason for distinction of amphibian which has obligate aquatic life style during larval period. Amphibians have been widely accepted as animal model for the study of endocrine disruption in aquatic ecosystem at molecular as well as individual levels. There are increasing need for toxicological data in amphibians at multiple endpoints for management of contamination and development of safety guidelines. Here, we reviewed toxicological information about toxicity of heavy metals (arsenic, cadmium, chromium, copper, lead, mercury, nickel, zinc) on various end-point of amphibian.

• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.188-197
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• 2003

Endocrine disrupting chemicals (EDCs) can alter hormone regulation that control reproductive system in animals. The effects of endosulfan, molinate, and alachlor that suspected to have examined disruption EDCs effect on a fish species of interest, Xiphophorus helleri (swordtail fish), were studied using vitellogenin (Vtg) and aromatase as diagnostic biomarkers. Induction of Vtg proteins was detected by RT-PCR in male fish treated with alachlor, and mixture of endosulfan and molinate in dose response manner. Also, induction of aromatase was detected by RT-PCR in male fish treated with alachlor, endosulfan, and mixture of endosulfan and molinate in sinlilar manner. In this study, swordtail fish exposed to endosulfan or molinate individually did not show any adverse effects. However, Vtg and aromatase expressions and apoptosis were detected in swordtail. fish exposed to the mixture of endosulfan and molinate. These results suggested that low concentrations of mixture of molinate and endosulfan individually do not affect swordtail fish, but may influence genital system, and induce apoptosis.

• Development and Reproduction
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• v.17 no.4
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• pp.469-475
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• 2013

In mammals, puberty is a process of acquiring reproductive competence, triggering by activation of hypothalamic kisspeptin (KiSS)-gonadotropin releasing hormone (GnRH) neuronal circuit. During peripubertal period, not only the external genitalia but the internal reproductive organs have to be matured in response to the hormonal signals from hypothalamic-pituitary-gonadal (H-P-G) axis. In the present study, we evaluated the maturation of male rat accessory sex organs during the peripubertal period using tissue weight measurement, histological analysis and RT-PCR assay. Male rats were sacrificed at 25, 30, 35, 40, 45, 50, and 70 postnatal days (PND). The rat accessory sex organs exhibited differential growth patterns compared to those of non-reproductive organs. The growth rate of the accessory sex organs were much higher than the those of non-reproductive organs. Also, the growth spurts occurred differentially even among the accessory sex organs; the order of prepubertal organ growth spurts is testis = epididymis > seminal vesicle = prostate. Histological study revealed that the presence of sperms in seminiferous tubules and epididymal ducts at day 50, indicating the puberty onset. The number of duct and the volume of duct in epididymis and prostate were inversely correlated during the experimental period. Our RT-PCR revealed that the levels of hypothalamic GnRH transcript were increased significantly on PND 40, suggesting the activation of hypothalamic GnRH pulse-generator before puberty onset. Studies on the peripubertal male accessory sex organs will provide useful references on the growth regulation mechanism which is differentially regulated during the period in androgen-sensitive organs. The detailed references will render easier development of endocrine disruption assay.