• Environmental Analysis Health and Toxicology
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• v.14 no.1_2
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• pp.55-63
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• 1999

Endocrine disrupting chemicals probably cause the cytological or/and morphological changes of germinal cells in gonad. Accordingly, this study was aimed to make sure that the effect of hormone-mimicking chemicals on gonad morphology such as decrease of germinal cells, inhibition of cellular maturation and change in the ratio of germinal cells in the different developmental phase can be observed by histopathological procedures and can be a useful bio-indicator for the evaluation of endocrine disruption by environmental chemicals. In this experiment, female Japanese medaka were exposured to quercetin, a phytoestrogen, at the concentration of 100 $\mu\textrm{g}$/L. quercetin showed the significant decrease in the number and rate of vitellogenic follicular oocytes in the treated group for 4 and 6 weeks. The weak development of yolk could be also observed. We could conclude that quercetin has anti-estrogenic or androgen-like potency by exerting the inhibition effect on oogenesis in fish female- gonad. From the result of this study, the applied methods and techniques can be evaluated to be a useful biomonitoring means for water pollution, expecting a good result of the subsequent study on apoptosis.

• 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.

• Environmental Mutagens and Carcinogens
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• v.22 no.4
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• pp.259-265
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• 2002

Phthalate analogues are a plasticizer and solvent used in industry. Phthalates were reported to be a potential carcinogen classified in the category of suspected endocrine disruptors. Most common human exposure to these compounds may occur with contaminated food. They may migrate into food from plastic wrap or may enter food from general environmental contamination. Since these substances are not limited to the original products, and enter the environment, they have become widespread environmental pollutants, thus leading to a variety of phthalates that possibly threaten the public health. Concern about their use has been mounting. To screen and elucidate the endocrine disrupting activity and their mechanism of phthalate analogues, first of all, E-screen assay was performed in MCF7 human breast cancer cells with seven phthalate analogues. In this cell proliferation assay, only dibutyl phthalate (DBP) showed weak estrogenic activity. Also the yeast-based transcription assay to assess the interactions of DBP with the estrogen, androgen, and progesterone receptors was conducted. DBP in the concentration ranges from 10$^{-16}$ to 10$^{-11}$ M was active in the estrogen transcriptional assay, but it did not show the effect on $\beta$-galactosidase activity in the progesterone and androgen transcriptional assays. These data indicate that DBP shows estrogenic potential and can be classified as weak and/or suspected endocrine disrupting chemicals.

• Journal of Nutrition and Health
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• v.36 no.5
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• pp.452-458
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• 2003

Soybean is a rich source of isoflavones such as genistein and daidzein. Soy isoflavones have both weak estrogenic and anti-estrogenic effects and are structurally similar to tamoxifen, an agent that has an effect similar to that of estrogen in terms of reducing postmenopausal bone loss. The purpose of this study was to determine the effects of differences in protein source (casein vs soy) and isoflavone levels (reduced vs higher levels) on selected bone markers and hormones in growing male rats. Thirty weanling Sprague-Dawley young rats were divided into 3 groups: The control group was fed a casein-based diet, the soy concentrate group was fed soy protein with totally reduced isoflavones content (isoflavones 0.07 mg/g protein), and the soy isolate group was fed soy protein with a higher than normal isoflavones content (isoflavones 3.4 mg/g protein). The degree of bone formation was estimated by measuring serum osteocalcin and alkaline phosphoatase (ALP). By determining collagen cross-linkage by immunoassay and correcting with creatinine values, the bone resorption rate was compared. Serum osteocalcin, growth hormone, estrogen and calcitonin were analyzed using radio immunoassay kits. The bone formation marker and ALP activity were differentiated by protein source, showing higher values than casein in feeding either soy isolate or soy concentrate. In this study using growing rats, the differences in isoflavone contents were not a significant factor in either bone formation or bone reaborption markers. Moreover, the soy isolate group had significantly higher levels of growth hormone than the casein group. The findings of this study suggest that growth hormone is partially responsible for its bone-formation effects in young growing rats. Soy protein and the isoflavones in soy protein are beneficial for bone-formation in growing male rats. Therefore, exposure to soy protein and isoflavones early in life may have long-term health benefits in preventing bone diseases such as osteoporosis. Further study to evaluate the mechanism of action of isoflavones on bones is warranted. (Korean J Nutrition 36(5): 452∼458, 2003)

• Development and Reproduction
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• v.20 no.4
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• pp.349-357
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• 2016

The present research was chiefly designed to determine the effect of the treatment of estrogenic agonist, estradiol benzoate (EB), or antiandrogenic compound, flutamide (Flu), at the weaning age on the expression of connexin (Cx) isoforms in the caudal epididymis of adult male rat. Animals were subcutaneously administrated with a single shot of either EB at a low-dose ($0.015{\mu}g$ of EB/kg body weight (BW)) or a high-dose ($1.5{\mu}g$ of EB/kg BW) or Flu at a low-dose ($500{\mu}g$ of EB/kg BW) or a high-dose (5 mg of EB/kg BW). Expressional changes of Cx isoforms in the adult caudal epididymis were examined by quantitative real-time PCR analysis. The treatment of a low-dose EB caused significant increases of Cx30.3, Cx31, Cx32, and Cx43 transcript levels but reduction of Cx31.1, Cx37, and Cx45 expression. Exposure to a high-dose EB resulted in very close responses observed in a low-dose EB treatment, except no significant expressional change of Cx37 and a significant induction of Cx40. Expression of all Cx isoforms, except Cx45, was significantly increased by a low-dose Flu treatment. Expressional increases of all Cx isoforms were detected by a high-dose Flu treatment. The current study demonstrates that a single exposure to estrogenic or antiandrogenic compound during the early postnatal developmental period is sufficient to disrupt normal expression of Cx isoforms in the adult caudal epididymis.

• Korean Journal of Food Science and Technology
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• v.51 no.4
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• pp.361-368
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• 2019

The present study aimed to evaluate the effect of Dendropanax morbifera (DM) extract on postmenopausal syndrome and to develop DM extract as an alternative for hormonal therapy. The following seven groups of rats; normal control (sham), ovariectomized (OVX) control, Punica granatum (PG)-treated group (770 mg/kg), estradiol treated group (0.5 mg/kg), and three DM-treated groups (200, 500, 1000 mg/kg) were compared. Indicated compounds were administrated once a day for eight weeks. To evaluate the estrogenic effect of DM extract, western blot analysis was performed on the liver tissue to confirm the expression of estrogen receptor ($ER-{\alpha}$, $ER-{\beta}$). Our analysis showed that after DM administration, collagen cross-linked C-telopeptide (CTX) value decreased while $ER-{\alpha}$ protein expression increased in a dose-dependent manner through the MAPK/ERK pathway in OVX rats. These results suggest that Dendropanax morbifera exerts estrogenic effect by inducing estrogen receptor expression and activating MAPK/ERK pathway.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.117-120
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• 2000

For detecting toxicity of endocrine disruptors (EDs), rapid, sensitive, and simple methods are needed. Therefore, in this study, a new method in which the different toxic effect of EDs can be monitored using 4 different recombinant bacteria was designed and evaluated. It was found that the recombinant bacteria could monitor the toxic effect, not estrogenic effect, due to EDCs through the measurement of bioluminescence and cell growth rate, which were shown to depend upon a form of cellular toxicity, such as DNA damage, protein damage, oxidative damage, and membrane damage. In addition, it was found that the damage done by EDCs can be divided into several groups based upon the toxic mechanisms of the EDCs

• Journal of the Korean Applied Science and Technology
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• v.24 no.3
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• pp.211-218
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• 2007

Based on the Benzoflex (Vesicol Chemical Co.) as PVC plasticizer substituents for Di-n-octyl phthalate (DOP), a series of new aromatic carboxylic acid ester compounds were designed as plasticizers, synthesized, and screened for the endocrine disrupting activity. 2-Hydroxybenzoic acid (1) and 2-methoxybenzoic acid (2) as the commercially available starting materials were reacted with diethylene glycol (3) in the presence of p-toluenesulfonic acid using Dean-Stark column to give diethylene glycol di-(2-hydroxy)benzoate (4, KH01) and diethylene glycol di-(2-methoxy)benzoate (5, KH02), respectively. And diethylene glycol di-(3-pyridinyl) ester (7, KH03) and dipropylene glycol di-(3-pyridinyl) ester (9, KH04) were obtained in high yields by treatment of nicotinoyl chloride (6) with diethylene glycol (3) and dipropylene glycol (8) in the presence of triethylamine as a base. To determine the estrogenic disrupting effect of new synthetic phthalate analogues, E-screen assay method was used. Of these compounds, 4 (KH01) was found to be compound without endocrine disrupting effect.

• Korean Journal of Environmental Biology
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• v.22 no.4
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• pp.479-486
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• 2004

Phytoestrogens display estrogen-like activity because of their structural similarity to human estrogens and exhibit high affinity binding for the estrogen receptors (ERs). The prevalence of phytoestrogens in our diets and the biological effects that they may cause need to be fully examined. ER is the ancestral receptor from which all other steroid receptors have evolved. Although phytoestrogens serve specific signaling functions between the plants and insects, fungi, and bacteria, many chemical signals are often misinterpreted as estrogenic signals in non-target organisms such as vertebrates. There are no ERs in plants or in their most common partners, insects. However, Rhizobium soil bacteria have NodD proteins which is an intended target of phytoestrogen signaling and share genetic homology with the ER. These two evolutionarily distant receptors both recognize and respond to a shared group of chemical signals and ligands, including both agonists and antagonists. This review briefly summarizes estrogen and estrogen receptors, kinds of important phytoestrogens, their health effects as well as some of the evolutionary aspects of mechanism by which phytoestrogen mimics the endogenous ER signaling in our body.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.184-184
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• 2003

Endosulfan is one of the organochlorine pesticides, well-known endocrine disruptors (EDs). Many EDs show the estrogenic effect. Estrogen is a group of hormones that play an important role in mammary gland function and implicated in mammary carcinogenesis. In the present study. using mouse mammary gland organ culture (MMOC) system. we studied the the effects of endosulfan on nodule like alveolar lesion (NLAL) formation in the mouse mammary gland development. (omitted)