• Korean Journal of Veterinary Research
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• v.35 no.1
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• pp.39-44
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• 1995

Using immunohistochemical technique, three endocrine cell types were observed in the GIT of the Korean salamander, Hynobius leechii. BPP-immunoreactive cells were distributed from the pyloric region to the small intestine. A moderated number of somatostatin-immunoreactive cells were restricted to the pyloric region. 5-HT-immunoreactive cells were demonstrated throughout the GIT, reaching a peak in the pyloric region. The presence of BPP- and 5-HT-immunoreactive cells are identified for the first time in Hynobius leechii.

• Development and Reproduction
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• v.18 no.4
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• pp.187-195
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• 2014

Polycyclic aromatic hydrocarbons (PAHs), which are ubiquitous in the air, are present as volatile and particulate pollutants that result from incomplete combustion. Most PAHs have toxic, mutagenic, and/or carcinogenic properties. Among PAHs, benzo[a]pyrene (B[a]P) and dimethylbenz[a]anthracene (DMBA) are suspected endocrine disruptors. The testis is an important target for PAHs, yet effects on steroidogenesis in Leydig cells are yet to be ascertained. Particularly, disruption of testosterone production by these chemicals can result in serious defects in male reproduction. Exposure to B[a]P reduced serum and intratesticular fluid testosterone levels in rats. Of note, the testosterone level reductions were accompanied by decreased steroidogenic acute regulatory protein (StAR) and $3{\beta}$-hydroxysteroid dehydrogenase isomerase ($3{\beta}$-HSD) expression in Leydig cells. B[a]P exposure can decrease epididymal sperm quality, possibly by disturbing the testosterone level. StAR may be a key steroidogenic protein that is targeted by B[a]P or other PAHs.

• BMB Reports
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• v.50 no.12
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• pp.615-620
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• 2017

Fibronectin (FN) plays important roles in the EMT in a variety of cancer cell types. However, the mechanism by which FN expression is regulated in tamoxifen-resistant (TamR) breast cancer cells has not yet been fully elucidated. Aberrant FN expression was associated with poor prognosis in patients with luminal type A breast cancer. In addition, FN was upregulated in TamR cells. To investigate the mechanism by which FN expression is regulated, we assessed the levels of phosphorylated Akt, JNK, and STAT3 and found that they were all increased in TamR cells. Induction of FN expression was dampened by LY294002 or AKT IV in TamR cells. Furthermore, FN expression was increased by constitutively active (CA)-Akt overexpression in tamoxifen-sensitive MCF7 (TamS) cells and colony formation of TamR cells was blocked by AKT IV treatment. Taken together, these results demonstrate that FN expression is upregulated through the PI-3K/Akt pathway in tamoxifen-resistant breast cancer cells.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2003.11a
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• pp.38-47
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• 2003

Relationships between accumulations of endocrine disruptors and abnormalities in the reproductive organs in the adult male striped field mice, Apodemus agrarius, were reviewed. High levels of phenolic compounds were detected in the mice collected at an agricultural village in Gaduck island and at a place having a sewage problem in Samdong-myeon, Namhae. High levels of organo tin compounds were found in the mice collected at Jiri Mt. a tourist resort. Considerably high levels of phenolic or organo tin compounds were detected in mice with shrunken reproductive organs accounting for 14∼42% of the mice examined in each area, which suggests that the abnormality of reproductive organs may be induced by the endocrine disruptors. This hypothesis is strongly supported by histological observations of shrunken reproductive organs, such as necrosis of testicular germ and epithelial cells. This was found not only in the mice with shrunken reproductive organs but also in the mice with enlarged reproductive organs, both had accumulated high levels of endocrine disruptors in general.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.190-191
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• 2003

Endometriosis is classically defined as the growth of endometrial glands and stroma at extrauterine sites. Although it is a common gynecological problem accompanied by chronic pelvic pain, infertility, and adhesion formation, the etiology of this disease is unknown. Endometriosis pathogenesis may involve endocrine and immune dysfunction since uterine endometrial growth is regulated by sex hormones in concert with bioactive mediators produced by uterine immune and endocrine cells. Thus, exposure to environmental toxicants disrupting endocrine and immune responses potentially affect the development and progression of endometriosis.

• Animal cells and systems
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• v.3 no.3
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• pp.269-273
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• 1999

The distribution and relative frequency of somatostatin-immunoreactive cells in the pancreas were studied during developmental stages (fetus, neonate, 1-month-old, 6-month-old and adult) of the Korean native goat by immunohistochemical methods. Somatostatin-immunoreactive cells were detected in the exocrine of all ages, in the endocrine portions (pancreatic islets) from the neonate, and in the pancreatic duct of the 1-month-old. The relative frequencies of these cells in the pancreatic islets increased with age. However, there were no age-related changes in the relative frequencies of somatostatin-immunoreactive cells in the exocrine and pancreatic duct. Generally, they were distributed in the interacinar spaces, the epithelium of the pancreatic duct, or dispersed in the peripheral zone of the pancreatic islets in all ages. However, clusters consisting of 3-4 cells were also found in the subepithelial connective tissues from the 1-month-old. In addition, the distributions in the endocrine portions of the adult were divided into two patterns: 1) they are dispersed in the marginal regions with moderate or low frequencies, or 2) in the inner zone with high frequencies.

• 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.

• Korean Journal of Environmental Biology
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• v.29 no.1
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• pp.74-80
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• 2011

In this study we present a mammalian cell culture model that allows to study the effect of endocrine disruptors (EDCs) on aromatase activity of aquatic amphibian, Bombina orientalis. Bombina orientalis aromatase gene was subcloned into a mammalian expression vector and subsequently transfected to mammalian cells. Although the protein expression level of Bombina orientalis aromatase was low, it had a significant aromatase activity. When EDCs were added to aromatase transfected cells, aromatase activity was significantly decreased. We report here that this system may be used to monitor the effect of EDCs on aromatase activity of aquatic organisms.

• Toxicological Research
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• v.16 no.2
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• pp.109-116
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• 2000

The purposes of our study were to optimize the conditions of the screening and testing methods for endocrine disruptors, to characterize these assays using several compounds with well-defined endocrine activity, and to compare the sensitivity between these assays currently undergoing validation. Two in vitro test systems, MCF-7 cells proliferation (E-screen assay) and competitive binding to estrogen receptors (ER) were selected to evaluate the estrogenic effects. 17$\beta$-Estradiol (E2) and diethylstilbestrol (DES) were used as a positive control in vitro test. Also, E2 and ethinyl estradiol (EE) were used as a positive control in vivo uterotrophic assay. In in vitro test, E2 and DES showed a strong estrogenic response at concentration of 1.0 nM. In uterotrophic assay, E2 (0.3 $\mu\textrm{g}$/kg) and EE (0.3 $\mu\textrm{g}$/kg) produced a significant increase in uterus and vagina weight in both immature and ovariectomized rats. Although we did not com-pared the specificity between in vivo and in vitro assays, these assay systems may serve as a good tool for endocrine disruptors screening methods. Our data indicate that these assay systems exhibit some difference in their sensitivity to the same estrogenic compounds. Therefore, as a first rapid screening assay for estrogenic activity qf unknown chemicals, at least two assay systems should probably be carried out with a view of high sensitivity and standardization conditions. Also, a careful validation tests are necessary to obtain a reasonable degree of reproducibility.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.22-27
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• 1990

The gastro-endocrine cells were examined in the fundic region of stomach of the frog, Rana rugosa, by transmission electron microscope. In the present paper, at least three kinds of cell type distributed in this region were idendfted according to their morphological charactedstics based on the size, shape and electron density of the secretory granules. Type I cells were characterized by the presence of round or oval granules (300-5OOnm in diameter) with high electron density. The granules showed a wide lucent between the contents and the limiting membrane. This cell was reminiscent of the ECL cell in the human alimentary mucosa. Type II cells were characterized by the presence of spherical or oval granules (11O-230nm in diameter) with low or high electron density. The granules showed a clear halo between the homogenous contents and the limiting membrane. This cell was reminiscent of the G cell in the human alimentary mucosa. Type Ill cells were characterized by the presence of elongated oval or pheomorphic granules (50-2OOnm in diameter) with low or moderate electron density and abundant microfilament bundles in the cytoplasm. The granules contained a very thin halo.