• Molecules and Cells
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• 제41권3호
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• pp.234-243
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• 2018

In recent years, the interest towards the relationship between incretins and bone has been increasing. Previous studies have suggested that glucagon-like peptide-1 (GLP-1) and its receptor agonists exert beneficial anabolic influence on skeletal metabolism, such as promoting proliferation and differentiation of osteoblasts via entero-osseous-axis. However, little is known regarding the effects of GLP-1 on osteoblast apoptosis and the underlying mechanisms involved. Thus, in the present study, we investigated the effects of liraglutide, a glucagon-like peptide-1 receptor agonist, on apoptosis of murine MC3T3-E1 osteoblastic cells. We confirmed the presence of GLP-1 receptor (GLP-1R) in MC3T3-E1 cells. Our data demonstrated that liraglutide inhibited the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, as detected by Annexin V/PI and Hoechst 33258 staining and ELISA assays. Moreover, liraglutide upregulated Bcl-2 expression and downregulated Bax expression and caspase-3 activity at intermediate concentration (100 nM) for maximum effect. Further study suggested that liraglutide stimulated the phosphorylation of AKT and enhanced cAMP level, along with decreased phosphorylation of $GSK3{\beta}$, increased ${\beta}-catenin$ phosphorylation at Ser675 site and upregulated nuclear ${\beta}-catenin$ content and transcriptional activity. Pretreatment of cells with the PI3K inhibitor LY294002, PKA inhibitor H89, and siRNAs GLP-1R, ${\beta}-catenin$ abrogated the liraglutide-induced activation of cAMP, AKT, ${\beta}-catenin$, respectively. In conclusion, these findings illustrate that activation of GLP-1 receptor by liraglutide inhibits the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation through $cAMP/PKA/{\beta}-catenin$ and $PI3K/Akt/GSK3{\beta}$ signaling pathways.

• 대한수의학회지
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• 제30권4호
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• pp.383-394
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• 1990

The gastrointestinal endocrine cells of the Pond tortoise, Amyda sinensis were studied immunohistochemically, and somatostatin-, gastrin/cholecystokinin(GAS/CCK)-, glucagon-, 5-hydroxytryptamine(5-HT)-, insulin- and chromogranin-immunoreactive cells were revealed. The characteristic findings of the regional distribution and relative frequency of these immunoreative cells in the gastrointestinal tract of the Pond tortoise were as follows; A few somatostatin-immunoreactive cells were distributed from the segment I to the segment V. GAS/CCK-immunoreactive cells were found from the segment III to the segment VII. These cells were numerous in the segment III and a few in the other segments. A few glucagon-immunoreactive cells were found in the segment I and rare in the segment II. 5-HT-immunoreactive cells were found throughout the gastrointestinal tract. Numerous numbers of them were found in the segment I, while moderate or a few in the other segments. Insulin-immunoreactive cells were distributed from the segment II to the segment IX. Moderate numbers of them were found in the segment VIII and IX, while a few in the other segments. Chromogranin-immunoreactive cells were found from the segment III to the segment VI. Moderate numbers of these cells were found in the segment IV and V, while a few in the other segments. BPP-immunoreactive cells were not observed throughout the gastrointestinal tract of the Pond tortoise, Amyda sinensis.

• 대한수의학회지
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• 제32권4호
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• pp.523-529
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• 1992

아프리카발톱두꺼비(Xenopus laevis)의 위장췌내분비세포를 면역조직화학적으로 관찰하였던 바 5-HT면역반응세포들은 중등도로 전장관에 고루 분포하였다. Gas/CCK면역반응세포는 유문부 장선의 기저부와 십이지장 점막상피에서 출현하였다. 소수의 glucagon면역반응세포는 위저부에서 약하게 반응하였고, 췌장에서는 외분비부에서만 관찰되었다. 직장을 제외한 전장관과 췌도 주변부 및 외분비부에서 somatostatin면역반응세포가 관찰되었다. CGs와 insulin면역반응세포는 전장관에서 관찰할 수 없었다. 그러나 insulin세포는 췌도의 중앙부와 외분비부에서 단독으로 출현하였다.

• Animal cells and systems
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• 제4권2호
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• pp.187-193
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• 2000

Regional distribution and relative frequency of endocrine cells in the pancreas of the red-eared slider, Trachemys scripta elegans, were investigated by immunohistochemical methods. Chromogranin (Cg) A-, serotonin-, insulin-, glucagon-, somatostatin-, bovine pancreatic polypeptide (BPP)- and human pancreatic polypeptede (HPP)-immunoreactive cells were identified in this study. Most of immunoreactive cells in the exocrine and endocrine pancreas (Langerhans islet) were generally spherical or spindle-shaped (open-typed cell), while occasionally cells round in shape (close-typed cell) were found in the basal portion or interepithelial regions of the pancreatic duct. These immunoreactive cells were located in the exocrine, endocrine pancreas and/or basal or interepithelial portion of the pancreatic duct. Serotonin-immunoreactive cells were found in the basal portion of epithelia of the pancreatic duct at a low frequency and interacinar region of the exocrine at a moderate frequency. Insulin-immunoreactive cells were found in the central portion of the endocrine pancreas, interacinar regions of the exocrine pancreas and basal portion of the epithelia of the pancreatic duct at high, moderate and low frequencies, respectively. Glucagon-immunoreactive cells were detected in the periphery of the endocrine pancreas, interacinar region of the exocrine pancreas and basal portion of the epithelia or interepithelia of the pancreatic duct at high, moderate and moderate frequencies, respectively. Somatostatin-immunoreactive cells were dispersed in the whole area of the endocrine pancreas, interacinar regions of exocrine pancreas and basal portion of the epithelia or interepithelia of the pancreatic duct at a moderate frequency. BPP- and HPP-immunoreactive cells were detected in the iinteracinar region of the exocrine pancreas at moderate and hige frequencies, respectively. However, no Cg A- and motilin-immunoreactive cells were detected in this study.

• 한국동물학회지
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• 제27권4호
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• pp.199-212
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• 1984

대장균의 세포질내에 존재하는 단백질 분해효소(protease Ci)를 추출하여 그 성질을 조사하였다. 이 효소는 insulin, glucagon 및 bovine growth hormone을 분해시키나, bovine serum albumin, casein 및 globin 등은 분해시키지 않는다. 이 효소의 native 한 상태에서의 분자량은 120,000이며, 54,000 dalton의 동일한 2개의 subunit로 구성되어 있다. Protease Ci의 최적 pH는 7.5이며 등전점은 5.5이다. 이 효소는 o-phenanthroline에 의해 저해되며, $Mn^++나 Co^++$와 같은 metal 이온들에 의하여 활성화되므로 metalloprotease임을 알 수 있다. 이 효소는 p-hydroxymercuribenzoate에 의해서 크게 저해되나 sulfhydryl protease의 specific한 저해제인 Ep475와 leupeptin에 의해서는 영향을 받지 않는다. 대장균 세포내에서는 또 다른 insulin 분해효소 (protease Pi)가 존재하는데, 이 효소는 periplasm에 존재하므로 protease Ci와는 다르다.

• 대한수의학회지
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• 제39권3호
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• pp.448-454
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• 1999

The regional distribution and relative frequency of the endocrine cells in the pancreas of the bean goose were investigated by immunohistochemical methods using 6 types of the specific antisera. Spindle shaped serotonin-immunoreactive cells were detected in the exocrine portions. Spherical or spindle shaped glucagon-immunoreactive cells were observed in the exocrine and dark and mammalian type islets. In the dark type islets, numerous cells were dispersed throughout whole islets but they were located in the peripheral regions of the mammalian type islets. No glucagon-immunoreactive cells were detected in light type islets. Round or spherical shaped insulin-immunoreactive cells were observed in the exocrine and dark, light and mammalian type islets. They were observed in the exocrine regions with a few numbers. Extremely rare cells were detected in central portion of the dark type islets but moderate to numerous cells were found in the central regions of the mammalian and light type islets, respectively. Spherical or spindle shaped somatostatin-immunoreactive cells were observed in the exocrine and dark, light and mammalian type islets. A few single cells were detected in the exocrine portions. In the dark type islets, numerous cells were dispersed throughout whole islets but a few to moderate numbers of cells were located in the peripheral regions of the light and mammalian type islets. Moderate numbers of the bovine pancreatic polypeptide-immunoreactive cells were found in the exocrine portions with round, spherical or spindle shape. But no bovine Sp-1/chromogranin-immunoreactive cells were observed in this study.

• 대한수의학회지
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• 제39권6호
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• pp.1038-1048
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• 1999

The regional distributions and relative frequencies of the gastrointestinal endocrine cells in the bean goose (Anser fabalis Latham) were investigated by immunohistochemical methods using bovine Sp-1/chromogranin (CG), serotonin, gastrin, cholecystokinin (CCK)-8, somatostatin and glucagon antisera. BCG-immunoreactive cells were widespread throughout the gastrointestinal tract (GIT) with moderated frequencies except for the gizzard and proventriculus which were a few frequencies. Serotonin-immunoreactive cells were detected throughout the GIT except for the proventriculus and gizzard. These cells were observed in the pylorus with rare frequencies but numerous cells were detected in the intestinal tract. Gastrin-immunoreactive cells were restricted to the gizzard, pylorus and duodenum. These cells were most predominant in the pylorus and a few or rare in the gizzard and duodenum, respectively. CCK-8-immunoreactive cells were observed from the gizzard to ileum. The highest frequencies of endocrine cells were observed in the duodenum. These cells were increased from the gizzard to duodenum but thereafter decreased. Somatostatin-immunoreactive cells were detected in the GIT except for the large intestine. In the proventriculus and pylorus, numerous immunoreactive cells were demonstrated but a few cells were present in the other regions. Glucagon cells were observed in the gizzard, pylorus, ileum, colon and rectum with a few or moderated numbers.

• Journal of Ginseng Research
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• 제22권1호
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• pp.51-59
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• 1998

In this study, rat hepatocytes known to have active glucose metabolism were obtained to investigate the hypoglycemic action of fat soluble fraction of red ginseng by using the liver perfusion technique and incubated in two different media-one containing insulin and glucagon (control group), and the other containing glucagon only The activities of main regulating enzymes, such as glucokinase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenate, and glucose 6-phosphatase, related to metabolic pathways of glucose in these two kinds of hepatocytes were compared between these two groups and the effects of addition of fat soluble fraction ($10^1$~$10^4$%) from red ginseng to these two groups on these enzymes were also detected. The results were as follows. The specific activity of enzymes such as glucokinase, flucorse 6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase related to glucose-consuming pathways of insulin-deficient group was much less than control one. However, their decreased activity was recovered after the addition of fat-soluble fraction at all range of concentrations. The specific activity of these enzymes after the addition of ginseng components to the control group was also increased. On the other hand, the specific activity of glucose 6-phosphatase related to glucose-producing pathway of insulin-deficient group was much higher than control one, but their increased activity was decreased obviously after the addition of fat soluble fraction at all range of concentrations. The same results were observed after the addition of fat-soluble fraction to the control group. These results suggest that the red ginseng saponin components might be effective on diabetic hyperglycemia by regulating the activity of enzymes related to glucose metabolism directly and/or indirectly. The effects of fat-soluble fraction ($10^2$%) and ginsenosides (mixture, $Rb_1$ and $Rg_1$, $10^4$%) on hypoglycemic action were compared. As a result, they showed considerable effect on hyperglycemia, but the best eff ect on the activities of glucokinase and glucose 6-phosphate dehydrogenase was appeared by ginsenoside $Rb_1$ and that of 6-phosphogluconate dehydrogenase and glucose 6-phosphatase was by ginsenoside mixture.

• 약학회지
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• 제52권5호
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• pp.345-354
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• 2008

This study was designed to investigate the anti-diabetic effect and mechanism of Korean red ginseng extract through transcriptomics in C57BL/KsJ db/db mice. The db/db mice were randomly divided into six groups: diabetic control group (DC), red ginseng extract low dose group (RGL, 100 mg/kg), red ginseng extract high dose group (RGH, 200 mg/kg), metformin group (MET, 300 mg/kg), glipizide group (GPZ, 15 mg/kg) and pioglitazone group (PIO, 30 mg/kg), and treated with drugs once per day for 10 weeks. At the end of treatment, we measured blood glucose, insulin, hemoglobin A1c (HbA1c), triglyceride (TG), adiponectin, leptin, non-esterified fatty acid (NEFA). RGL-treated group lowered the blood glucose and HbA1c levels by 19.6% and 11.4% compared to those in diabetic control group. In addition, plasma adiponectin and leptin levels in RGL-treated groups were increased by 20% and 12%, respectively, compared to those in diabetic control. Morphological analyses of liver, pancreas and epidydimal adipose tissue were done by hematoxylin-eosin staining, and pancreatic islet insulin and glucagon levels were detected by double-immunofluorescence staining. RGL-treated group revealed higher insulin contents and lower glucagon contents compared to diabetic control. To elucidate an action mechanism of Korean red ginseng, DNA microarray analyses were performed in liver and fat tissues, and western blot and RT-PCR were conducted in liver for validation. According to hierarchical clustering and principal component analysis of gene expression Korean red ginseng treated groups were close to metformin treated group. In summary, Korean red ginseng lowered the blood glucose level through protecting destruction of islet cells and shifting glucose metabolism from hepatic glucose production to glucose utilization and improving insulin sensitivity through enhancing plasma adiponectin and leptin levels.

• 한국식품영양과학회지
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• 제42권6호
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• pp.885-891
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• 2013

유색보리와 귀리를 이용한 당뇨환자용 즉석죽의 당뇨 개선 효과를 in vivo를 통하여 확인하고 다음과 같은 결과를 얻었다. Type II 당뇨병 모델 생쥐(C57BLKS/J lar-$+Lepr^{db}/+Lepr^{db}$)의 실험종료 후 혈당의 농도는 대조군에서는 $426.0{\pm}15.4$ mg/dL이었으나, 실험군에서는 $352{\pm}12.2$ mg/dL로 약 17.4% 감소하였다. Streptozotocin으로 유발시킨 당뇨병 모델 SD계 rat의 실험종료 후 혈당의 농도는 대조군에서 $514.0{\pm}17.6$ mg/dL이었으나, 실험군에서는 $296.4{\pm}13.2$ mg/dL로 42.3% 감소하였다. Type II 당뇨병 모델 생쥐의 혈중내 인슐린 농도는 대조군에서 $7.9{\pm}0.5$ ng/mL이었으나, 실험군에서는 $12.8{\pm}1.1$ ng/mL로 약 38.3% 증가하였다. Type II 당뇨병 모델 생쥐의 췌도 내 인슐린 분비세포와 glucagon like peptide-1 분비세포에 대한 면역염색 반응은 실험군에서 대조군에 비해 췌도 내 인슐린 분비세포에 대한 면역염색 반응이 강하게 관찰되었고, streptozotocin으로 유발시킨 당뇨병 모델 SD계 rat의 췌도 내 인슐린 분비세포 및 glucagon like peptide-1 분비세포에 대한 면역염색 반응 또한 실험군에서 대조군에 비하여 인슐린 분비세포에 대한 면역염색 반응이 강하게 관찰되었다. 이상의 실험결과로 당뇨환자용 즉석죽은 당뇨병 유발 쥐들에서 췌도 내 인슐린 분비세포 기능의 활성화를 통한 인슐린의 분비를 촉진시키고, 혈당을 저하시킴을 알 수 있었다.