• Environmental Analysis Health and Toxicology
• /
• 제22권3호
• /
• pp.227-233
• /
• 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
• /
• 제17권2호
• /
• pp.47-52
• /
• 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.

• 대한핵의학회지
• /
• 제18권1호
• /
• pp.39-44
• /
• 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
• /
• 제11권6호
• /
• pp.534-538
• /
• 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
• /
• 제3권2호
• /
• pp.187-191
• /
• 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.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 1997년도 학술발표회
• /
• pp.20-20
• /
• 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)

• 대한수의학회지
• /
• 제35권1호
• /
• pp.45-54
• /
• 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.

• 핵의학기술
• /
• 제15권1호
• /
• pp.117-120
• /
• 2011

Glucagon은 췌장 Langerhans섬 ${\alpha}$-세포에서 합성 분비되며, 기능으로는 간 당원분해, 지방분해, 인슐린분비 촉진 작용 등이 있다. Glucagon의 측정은 Glucagon 과잉증에 의한 당뇨병, 특발성 Glucagon 결손증, 불안정 당뇨병에서 저혈당의 진단을 하기위해 실시된다. Glucagon 측정시 세 가지 주의를 요하는데, 첫째, Aprotinin이 첨가된 EDTA tube에 채혈해야 하고 둘째, Plasma를 분리하여 Glass tube에 냉동 보관하여야 하고, 마지막으로 검사시에도 Glass tube에서 측정을 해야 한다. 이에 우리는 EDTA tube에 Aprotinin의 유무에 따른 결과 비교, 검체 보관 용기의 차이에 따른 비교(Plastic tube/ Glass tube), 측정용기에 따른 비교(Plastic tube/Glass tube)를 하여, 세 가지가 결과에 미치는 영향을 알아보고자 한다. 성별 구분 없이 건강검진에서 정상 소견을 보인 성인 40명을 대상으로 실험하여 대조군과 세가지 다른 실험군의 Glucagon 결과를 비교하였다. Aprotinin첨가한 EDTA 용기에 채혈 후, 검체를 Glass tube에 3일 냉동 보관하여 Glass tube에서 실험(대조군)한 결과와 Aprotinin첨가하지 않은 EDTA 용기에 채혈한 결과(실험군1), Plastic tube에 3일 냉동 보관한 후의 결과(실험군2), Plastic tube에서 실험(실험군3)한 결과를 비교하였다. 통계적인 분석은 SPSS를 이용한 paired t-test와 단순선형회귀분석을 실시하였고 시약은 상품화된 Siemens사의 Glucagon RIA kit를 사용하였다. Aprotinin이 첨가된 EDTA 용기에 채혈하여 실험한 결과와 Aprotinin이 첨가되지 않은 EDTA용기에 채혈하여 실험한 상관계수는 r=0.783(p=0.064)를 보였다. 검체 분리 후 Plastic tube에서 3일 냉동 보관하여 실험한 결과는 Glass tube의 결과에 비해서 유의하게 낮게 나타났다(r=0.979, p=0.005). 또 측정 시 Plastic tube를 사용한 결과도 Glass tube에서 실험한 결과보다 유의하게 낮게 나타났다(r=0.754, p<0.001). Glucagon 검사 시에는 단백 분해효소 억제제인 Aprotinin이 첨가된 EDTA tube 사용이 권장되며, Plastic tube 사용 시 환자의 결과가 유의하게 낮게 나타나므로 검체는 분리 후 Glass tube에 냉동 보관하고 Glass tube에서 실험하여야 한다.

• 대한수의학회지
• /
• 제32권4호
• /
• pp.497-510
• /
• 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
• /
• 제18권6호
• /
• pp.1076-1080
• /
• 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.