• Environmental Analysis Health and Toxicology
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• v.22 no.3
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• pp.227-233
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• 2007

It has been reported that hepatic glutathione (GSH) levels are decreased in diabetic patients, and glucagon increases hepatic efflux of GSH into blood. The signaling pathways responsible for mediating the glucagon effects on GSH efflux, however, are unknown. The signaling pathways involved in the regulation of GSH efflux in response to glucagon and insulin were examined in primary cultured rat hepatocytes. The GSH concentrations in the culture medium were markedly increased by the addition of glucagon, although cellular GSH levels are significantly decreased by glucagon. Insulin was also increased the GSH concentrations in the culture medium, but which is reflected in elevations of both cellular GSH and protein. Treatment of cells with 8-bromo-cAMP or dibutyryl-cAMP also resulted in elevation of the GSH concentrations in the culture medium. Pretreatment with H89, a selective inhibitor of protein kinase A, before glucagon addition markedly attenuated the glucagon effect. These results suggest that glucagon changes GSH homeostasis via elevation of GSH efflux, which may be responsible for decrease in hepatic GSH levels observed in diabetic condition. Furthermore, the present study implicates cAMP and protein kinase A in mediating the effect of glucagon on GSH efflux in primary cultured rat hepatocytes.

• Journal of Medicine and Life Science
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• v.17 no.2
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• pp.47-52
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• 2020

Glucagon regulates glucose and fat metabolism as well as being involved in the production of ketone bodies. The new antidiabetic drug, a sodium-glucose co-transporter-2 inhibitor, increases glucagon, and reduces the risk of cardiovascular death and hospitalization due to heart failure. The presence of metabolic syndrome is an important risk factor for cardiovascular diseases(CVD) in type 2 diabetes(T2DM) patients. We, thus, investigated the association between glucagon levels and metabolic syndrome in T2DM patients. This cross-sectional study involved 317 T2DM patients. Fasting and postprandial (30 min after ingestion of a standard mixed meal) glucagon levels were measured. Metabolic syndrome was defined according to the criteria of the International Diabetes Federation. A multiple regression logistic analysis was employed for statistical evaluation. A total of 219 (69%) subjects had metabolic syndrome. The fasting and postprandial glucagon levels did not differ between the group with metabolic syndrome and the group without. Postprandial glucagon levels increased significantly with the increase in the number of metabolic syndrome components, but the fasting levels did not. However, a hierarchical logistic regression analysis revealed that the postprandial glucagon levels did not contribute significantly to metabolic syndrome even after adjusting for other covariates. Fasting and postprandial glucagon levels are not associated with metabolic syndrome in T2DM patients. However, further studies are needed to investigate the relationship between glucagon and cardiovascular risk in patients with T2DM.

• The Korean Journal of Nuclear Medicine
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• v.18 no.1
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• pp.39-44
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• 1984

It is well known that glucagon, like insulin, is very important in the moment-to-moment control of the homeostasis of glucose, and of amino acids. Glucagon has been shown to have potent glycogenolytic, gluconeogenic and lipolytic activities. Attention to its role in the pathogenesis of diabetes mellitus and hypoglycemia has been also advanced recently. To evaluate the diurnal variation of plasma glucagon concentration, we measured serum glucose, insulin, and plasma glucagon every 30 minutes or every hour in 7 normal Korean adults. Results were as follows: 1) Although plasma glucagon concentration showed wide individual variations, it had a tendency to decrease after meals. After lunch and dinner, plasma glucagon concentration had gradually declined and reached its nadir at postprandial 2-2.5 hours. The minimal level of plasma glucagon was at 4 A.M. 2) Serum insulin:plasma glucagon ratios were increased promptly after meals. Especially after lunch, its peak was prominent $(3.65{\pm}1.95)$. The minimal level of serum insulin:plasma glucagon ratio appeared at 6 A.M.

• Bulletin of the Korean Chemical Society
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• v.11 no.6
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• pp.534-538
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• 1990

Glucagon was found to interact with DMPC vesicles electrostatically and hydrophobically. It appears that glucagon bound irreversibly to the vesicles through hydrophobic interaction was partially protected from the proteolysis by trypsin. Out of three possible sites, only the peptide bond preceded by Arg-18 was cleaved by a prolonged trypsin treatment. ${\alpha}$-chymotrysin did not affect the vesicle-bound glucagon. Based on these observations, possible structure of irreversibly bound glucagon on the vesicle surface is discussed.

• Animal cells and systems
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• v.3 no.2
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• pp.187-191
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• 1999

The distribution of glucagon-immunoreactive cells in the pancreas during various developmental stages (fetus, neonate, 1-month-old, 6-month-old and adult) of the Korean native goat was investigated by immunohistochemical methods. The varying distribution and frequency of glucagon-immunoreactive cells in the pancreas of the Korean native goat were observed. The glucagon-immunoreactive cells were detected in both exocrine and endocrine portions (pancreatic islets) at all developmental stages and also in ducts of the 6-month-old and adult. The relative frequencies of glucagon-immunoreactive cells increased in the pancreatic islets and ducts with age, but decreased in the exocrine portions. Generally, they were distributed in the interacinar spaces or marginal zone of the pancreatic islets during all stages of development. However, the cell distributions of the pancreatic islets in the neonate divided into two types: 1) ones which were distributed in the inner zone, and 2) others in the peripheral zone.

• Proceedings of the Korean Biophysical Society Conference
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• 1997.07a
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• pp.20-20
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• 1997

Glucagon fragments dimyristorylphosphatidylcholine(DMPC) liposomes into discoidal complex. The concentration of glucagon required to fragment the vesicles increases with increasing pH and the fragmentation appears to be the result of glucagon binding to the vesicles.(omitted)

• Korean Journal of Veterinary Research
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• v.35 no.1
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• pp.45-54
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• 1995

Pancreatic endocrine cells containing glucagon, insulin, somatostatin and pancreatic polypeptide were identified in the pancreas of the Korean native goat by using immunohistochemical method. Glucagon immunoreative cells were oval or fusiform in shape and located at the periphery of the pancreatic islets. Insulin immunoreactive cells were round or oval in shape and occupied throughout the pancreatic islets except the small area of the periphery. Somatostatin immunoreative cells were oval and elliptical, and mainly located at the periphery of the pancreatic islets. Some of these cells had a cytoplasmic process. Pancreatic polypeptide immunoreactive cells were elliptical or polyhedral and located at the periphery of the pancratic islets where two or more cells formed a cell cluster. The distribution rates of glucagon, insulin, somatostatin and pancreatic polypeptide immunoreactive cells were 24.4%, 44.3%, 13.2% and 18.1% respectively.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.117-120
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• 2011

Purpose: There are 3 warnings for Glucagon tests. First, EDTA tubes that already contain Aprotinin must be used for plasma collection. Second, for freezer storage of centrifuged plasma, glass tubes must be used. Last, glass tubes must be used for testing procedure. So we compared the glucagon results of next 3 situation to those of control group. First, We compared to results by tubes without Aprotinin and with aprotinin. Second, we compared to results by tubes(plastic vs glass) for plasma storage. Third, we compared to results by tubes(plastic vs glass) for testing. We tried to evaluate the results of the 3 different condition. Materials and Methods: 40 healthy adults were studied with normal results on the general medical check up and laboratory tests. We compared the results of 3 different condition belows: Blood were collected in EDTA tube containing aprotinin and plasma was stored in the glass tube for 3 days in a freezer and results were obtained by tests in the glass tubes. Results from EDTA plasma without aprotinin, results from platic tubes for freezer stroage, results from plastic tube when testing. Simple linear regression analysis and paired t-test using SPSS were done for statistical analysis. Commercial glucagon kit(RIA-method)which made by Siemens company were used. Results: Correlation coefficient between results of EDTA tubes with Aprotinin vs without Aprotinin was r=0.783 (p=0.064). Result of specimen in plastic tubes stored 3 days in a freezer showed lower value compared to those in glass tube(r=0.979, p=0.005). Also, results of testing in plastic tubes showed lower values than those testing in glass tubes. (r=0.754, p<0.001). Conclusion: It is recommended for glucagon determination to use EDTA tube with Aprotinin which is a inhibitor of protein breakdown enzyme. Results of plastic tube when storage and testing showed lower value than those of glass tubes, so it is recommended to store and test in glass tubes.

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.497-510
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• 1992

This study was attempted to comparative investigate the types and regional distribution of the endocrine cells in several vertebrates immunohistochemically using seven antisera. From carp pancreas could be observed 4 types which are insulin-, glucagon-, som- and BPP-immunoreactive cells. Insulin-immunoreactive cells were mainly distributed at the periphery and a few cells occupied the central region of the islets. Glucagon-immunoreactive cells were distributed at the periphery of the islets, and som - and BPP-immunoreactive cells were located at the central region. From frog pancreas could be observed 4 types which are insulin-, glucagon-, som- and BPP-immunoreactive cells. Insulin-immunoreactive cells were distributed throughout the islets. Som-immunoreactive cells were distributed at the periphery of the islets, and glucagon- and BPP-immunoreactive cells were found as single cell or as small groups located between the pancreatic acini. From snake pancreas could be observed 3 types which are insulin-, glucagon- and som -immunoreactive cells. Insulin-immunoreactive cells were distributed throughout the small islets, and they also were scattered at the periphery of the large islets. Glucagon-immunoreactive cells were distributed at the periphery of the islets, whereas som-immunoreactive cells were occupied the central region. From Ogolgae pancreas could be observed 4 types which are insulin-, glucagon-, som-and BPP-immunoreactive cells. Insulin-immunoreactive cells were distributed throughout the small islets, but at the periphery of the large one. Glucagon- immunoreactive cells were distributed at the periphery of the small islets and in the large islets showed scattering entired. Som-immunoreactive cells were distributed at the periphery of the small islets and in the large islets were located at the central region. A small numbers of BPP-immunoreactive cells were located at the periphery of the small islets and the exocrine regions. From the pancreas of the Korean native goat could be observed 6 types which are insulin-, glucagon-, som-, BPP-, 5-HT- and porcine-CG-immunoreactive cells. Insulin-immunoreactive cells were distributed throughout the islets. Som-immunoreactive cells were located at the periphery of the islets, but a tew were scattered at the central region of islets and in the epithelium of the secretory duct. Glucagon-, BPP-, 5-HT- and porcine CG-immunoreactive cells were distributed at the periphery of the islets. These findings indicated that the regional distribution patterns and cell types of pancreatic endocrine cells in vertebrates varies considerably among phylogenetically different vertebrates.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1076-1080
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• 2008

Glucagon, a peptide hormone produced by alpha-cells of Langerhans islets, is a physiological antagonist of insulin and stimulator of its secretion. In order to improve its bioactivity, we modified its structure at the C-terminus by amidation catalyzed by a recombinant amidase in bacterial cells. The human gene coding for glucagon-gly was PCR amplified using three overlapping primers and cloned together with a rat ${\alpha}$-amidase gene in plasmid pMGA. Both genes were expressed under control of the strong constitutive promoter of aph and secretion signal melC1 in Streptomyces lividans. With Phenyl-Sepharose 6 FF, Q-Sepharose FF, SP-Sepharose FF chromatographies and HPLC, the peptide was purified to about 93.4% purity. The molecular mass of the peptide is 3.494 kDa as analyzed by MALDI TOF, which agrees with the theoretical mass value of the C-terminal amidated glucagon. The N-terminal sequence of the peptide was also determined, confirming its identity with human glucagon at the N-terminal part. ELISA showed that the purified peptide amide is bioactive in reacting with glucagon antibodies.