• Korean Journal of Veterinary Research
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• v.42 no.1
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• pp.21-28
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• 2002

The regional distribution and relative frequency of the pancreatic endocrine cells in the ICR mouse were studied by immunohistochemical (PAP) method using four types of specific antisera against insulin, glucagon, somatostatin and human pancreatic polypeptide (PP). The pancreas of mice could be divided into three portions; pancreatic islets, exocrine and pancreatic ducts. Pancreatic islets, furthermore, were subdivided into three regions (central, mantle and peripheral region) according to their located types of immunoreactive cells. In the pancreatic islet portions, insulin-immunoreactive cells were located in the central and mantle regions but most of somatostatin-, glucagon- and PP-immunoreactive cells were detected in the mantle and peripheral regions with various frequencies. In addition, PP-immunoreactive cells were also found in the central regions of pancreatic islets of ICR mouse. In the exocrine portions, all four types of immunoreactive cells were demonstrated in the ICR mouse. In the pancreatic duct portions, insulin- and glucagon-immunoreactive cells were situated in the epithelial lining of ICR mouse with a few and rare frequencies, respectively. In addition, rare PP-immunoreactive cells were also demonstrated in the subepithelial regions of the pancreatic duct. However, no somatostatin-immunoreactive cells were demonstrated.

• Proceedings of the Zoological Society Korea Conference
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• 2001.04a
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• pp.98.2-98
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• 2001

No Abstract, See Full Text

• Journal of Embryo Transfer
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• v.28 no.2
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• pp.95-111
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• 2013

Worldwide there is concern about the continuing release of a broad range of environmental endocrine disrupting chemicals, including polychlorinated biphenyls, dioxins, phthalates, polybrominated diphenyl ethers (PBDEs), and other halogenated organochlorines persistent organic pollutants (POPs) into the environment. They are condemned for health adverse effects such as cancer, reproductive defects, neurobehavioral abnormalities, endocrine and immunological toxicity. These effects can be elicited via a number of mechanisms among others include disruption of endocrine system, oxidation stress and epigenetic. However, most of the mechanisms are not clear, thus several number of studies are ongoing trying to elucidate them in order to protect the public by reducing these adverse effects. In this review, we briefly limited review the process, the impacts, and the potential mechanisms of dioxin/dioxin like compound, particularly, their possible roles in adverse developmental and reproductive processes, diseases, and gene expression and associated molecular pathways in cells.

• Toxicological Research
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• v.22 no.1
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• pp.15-22
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• 2006

Many of endocrine disrupting chemicals induce effects via interaction with hormone receptors and responsive elements in target cells. We investigated endocrine disrupting effects of some food additives and contaminants including BHA, BHT, ethoxyquin, propionic acid, sorbic acid, benzoic acid, CPM, aflatoxin B1, cadmium chloride, genistein, TCDD and PCBs in yeast transformants expressing human steroid hormone receptors along with steroid responsive elements. The response limit of genetically recombinant yeast to $17{\beta}$-estradiol, testosterone and progesterone was $1{\times}10^{-16},\;1{\times}10^{-12}\;and\;1{\times}10^{-13}M$, respectively. BHT induced weak transcriptional activity in estrogen sensitive yeast, while BHA and sorbic acid interacted weakly with androgen receptor/responsive element. CPM induced transcriptional activities in all types of yeasts sensitive to steroid hormones. Zearalenone and genistein induced high transcriptional activation in estrogen sensitive yeast with relative potencies almost $10^8$ folds lower than $17{\beta}$-estradiol. TCDD induced transcriptional activation weakly in estrogen- and progesterone- sensitive yeasts. This study elucidated that recombinant yeast is a sensitive and high-throughput system and can be used for the direct assessment on chemical interactions with steroid receptors and responsive elements. Also, the present study raises the requirement of evaluation on the endocrine disrupting effects of BHT, BHA, sorbic acid, CPM and TCDD for their transcription activity in yeast screening system though weak in intensity.

• Applied Microscopy
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• v.16 no.2
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• pp.25-34
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• 1986

The endocrine cells of the stomach and duodenum of the pond tortoise (Amyda sinensis) have been studied by electron microscopy. At least six types of endocrine cells could be identified in these regions. Type I cells were characterized by having pleomorphic or medium sized granules ($100{\sim}430nm$ in diameter, mean; 290 nm) which were moderate in electron density. Type II cells were characterized by having pleomorphic or medium sized granules ($190{\sim}430nm$ in diameter, mean; 280 nm) which were high in electron density. Type III cells were characterized by having large oval or irregular granules($170{\sim}650nm$, mean: 430 nm) with wide vesicular halo which were high in electron density. Type IV cells were characterized by having round or medium sized granules($140{\sim}370nm$, mean; 240 nm) which were low to moderate in electron density and showed a very thin halo. Type V cells were characterized by having large round or oval granules($300{\sim}600nm$, mean; 410 nm) which were low to moderate in electron density and showed a dense core and a wide clear halo. Microfilaments were also found in the cytoplasm. Type VI cells were characterized by having round and small granules($100{\sim}220nm$, mean; 160 nm) which were low to moderate in electron density and showed a very thin halo or crystalline structure of the contents. Many microfilament bundles were also found in the cytoplasm.

• Korean Journal of Veterinary Research
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• v.30 no.3
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• pp.261-270
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• 1990

The gastrointestinal endocrine cells of the Korean native goat were studied immunohistochemically, and 5-HT-, somatostatin-, Gas/CCK-, glucagon-, chromogranin- and PP- immunoreactive cells were revealed. The characteristic findings of the regional distribution and relative frequency of these immunoreactive cells in the gastrointestinal tract of the Korean native goat were as follows. 5-HT-immunoreactive cells were more numerous in the small and large intestine than in the abdomen stomach. Somatostatin-immunoreactive cell were more numerous in the abdomen stomach than in the small and large intestine. Gas/CCK-immunoreactive cells were concentrated very numerously in the pyloric region with a few in the other regions. Moderate numbers of glucagon-immunoreactive cells were found in the small and large intestine, but a few of them were found in the abdomen stomach. Very numerous chromogranin-immunoreactive cells were detected throughout the gastrointestinal tract. PP-immunoreactive cells were observed moderate numbers in the large intestine with few in the ileum. No insulin-immunoreactive cell was found in the gastrointestinal tract.

• Molecular & Cellular Toxicology
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• v.1 no.3
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• pp.149-156
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• 2005

Di (n-ethylhexyl) phthalate (DEHP) is thought to mimic estrogens in their action, and are called endocrine disrupting chemicals. DEHP is used in numerous consumer products, especially those made of flexible polyvinyl chloride and have been reported to be weakly estrogenic. In this study, DEHP were tested for estrogenic properties in vitro models and with microarray analysis. First, the E-screen assay was used to measure the proliferation of DEHP in MCF-7 cells, a human breast cancer cell line. DEHP induced an increase in MCF-7 cell proliferation at concentration of $10^{-4}M$. Second, we carried out a microarray analysis of MCF-7 cells treated with DEHP using human c-DNA microarray including 401 endocrine system related genes. Of the genes analyzed, 60 genes were identified showing significant changes in gene expression resulting from DEHP. Especially, 4 genes were repressed and 4 genes were induced by DEHP compared to $17{\beta}-estradiol$. Among these genes, trefoil factor 3 (intestinal), breast cancer 1, early onset and CYP1B1 are involved in estrogen metabolism and regulation. Therefore it suggests that these genes may be associated with estrogenic effect of the DEHP on transcriptional level. The rationale is that, as gene expression is a sensitive endpoint, alterations of these genes may act as useful biomarkers to define more precisely the nature and level of exposure to kinds of phthalates.

• 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.

• 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.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.35-38
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• 2003

The parathyroid gland is probably the simplest endocrine organ in the body. The only cells of clinical significance are the parathyroid or chief cells. The primary signal that these cells listen to is calcium. Primary hyperparathyroidism is due to a parathyroid adenoma. The most common cause of hypercalcemia in veterinary medicine is hypercalcemia of malignancy associated with variety of neoplasms. Secondary hyperparathyroidism is due to a disease process, most commonly associated with renal and nutritional hyperparathyroidism. Primary and secondary hyperparathyroidism are markedly different in their clinical, laboratory, and pathogenic mechanism.