• 생명과학회지
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• 제15권1호
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• pp.87-93
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• 2005

본 연구에서는 Streptozotocin-유발 당뇨 쥐를 대상으로 8주 동안 운동 강도에 따른 혈당, 인슐린, 골격근 내 GLUT-4 발현 량과 GRP-78 발현량 변화를 관찰함으로써 당뇨 쥐의 혈당을 낮추는데 효과적인 운동 강도는 무엇이며, 기전적인 원인은 무엇인지를 밝히고자 실시되었다. 본 연구에서 Streptozotocin으로 당뇨를 유발시킨 흰쥐를 대상으로 운동 강도 처치에 따른 GLUT-4발현 량을 비교한 결과, 기본적으로 당뇨가 유발된 흰쥐의 GLUT-4 발현 량은 정상 쥐에 비해 현저하게 감소하는 것을 볼 수 있었다. 이중 8주 동안 저강도 운동 수행 한 쥐들의 경우는 정상 쥐 수준에 가까운 발현 량을 관찰 할 수 있었으며, 흰쥐 가자미 근 내 GRP-78 발현 량은 당뇨 유발 쥐의 경우 정상 쥐의 유의하게 증가한 것을 관찰할 수 있었고, 저강도 운동을 수행한 집단에서의 GRP-78 발현 량은 정상 흰쥐에서 발현되는 양에 비해 유의하게 높은 수준을 보이기는 했지만 당뇨 유발 대조군과 고강도 운동 군에 비해서는 유의하게 낮은 수준으로 나타났다. 결론적으로 저강도의 운동은 당뇨 질환자의 혈당을 낮추는 데 가장 효과적인 운동이라 할 수 있으며, 이러한 결과의 기전적인 원인은 저강도의 운동이 근육 내 GLUT-4의 증가로 세포내 당 유입을 촉진시킴으로 해서 나타난 사실이라 생각되며 이 같은 사실은 GRP-78의 발현 량의 감소로 확인할 수 있었다.

• Biomolecules & Therapeutics
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• 제4권4호
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• pp.398-401
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• 1996

The glucose transporters found in the plasma membrane of all animal cells are known to have 12 putative transmembrane domains. Among 7 cytoplasmic loops, the fourth loop is the largest one. Since previous studies showed that cofilin, an actin-modulating protein, was found to interact with the largest cytoplasmic loop of (Na, K)ATPase, we tested if cofilin interacts with the largest cytoplasmic loop of Glut4. We demonstrated by the two-hybrid system that the largest cytoplasmic loop of Glut4 did not show any interaction with cofilin, suggesting that cofilin is not required for the membrane targeting process of other membrane proteins but only for a P-type ATPase.

• BMB Reports
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• 제34권4호
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• pp.285-292
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• 2001

Insulin stimulates glucose uptake in muscle and adipose tissue and thus maintains normal blood glucose level in our body. Derangement of this process causes many grave health problems. Insulin stimulates glucose transport primarily by recruiting GLUT4 from its intracellular storage sites to the plasma membrane. The process is complex and involves GLUT4 trafficking through multiple subcellular compartments (organelles) and many protein functions, details of which are poorly understood. This review summarizes a recent development to isolate and characterize the individual intracellular GLUT4 compartments and to illustrate how this compartmental analysis will help to identify the insulin-sensitive step or steps in the insulin-induced GLUT4 recruitment in rat adipocytes. The review does not cover the recent exciting development in identification of many proteins implicated in this process.

• 대한임상전기생리학회지
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• 제1권1호
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• pp.73-85
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• 2003

The purpose of this study is to discuss and analyze the change of GLUT-4 and muscle fiber type of streptozotocin(STZ)-diabetic rats over a period of 6 weeks. We divided into four groups; I(aquatic exercise and feeding of Cordyceps militaris; n=6), test group II(feeding of Cordyceps miliaris; n=6), test group III(aquatic exercise; n=6), control group IV(non-treatment; n=6). After experimenting we measured the blood glucose, body weight, muscle fiber type and GLUT-4 protein content. The change of glucose levels decreased greater in group I than the other group. The body weight gain was lower in the all groups. The change femoris muscle fiber type, the size of muscle fiber TypeII lessened more than the one of Type I in group IV. Decrease of muscle fiber size more diminishment in group I than the other group. GLUT-4 protein quantity decrease in group IV compared to normal group. It was significantly increased in group. I, III compared to group IV. But there was more increase in group I (p<.001). These results suggest that GLUT-4 and muscle fiber type II decrease in STZ-diabetic rats and that when we apply aquatic exercise and feeding of Cordyceps militaris in diabetic rats over a period 6 weeks, it is increase GLUT-4 and the increase of insulin sensitivity of peripheral tissue. So it is considered to be helpful in improvement of glucose homeostasis and in prevent from muscle atrophy resulted from complication.

• The Korean Journal of Physiology
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• 제25권2호
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• pp.115-123
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• 1991

Molecular association of glucose transporters with the other proteins in the plasma membrane was assessed by gel electrophoresis and immunoblot techniques. Approximately $31.5{\pm}5.1%$ of GLUT-4, $64.8{\pm}2.7%$ of clathrin, 48.7% of total protein in the plasma membrane (PM) were found insoluble upon extraction with 1% Tx-100. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the Tx-100 insoluble PM fraction contained about 4 major polypeptides with apparent molecular weight of above 200, 100-120, 80 and 30-35 KDa that were readily removed upon wash with a high pH buffer which is known to remove clathrin and 0.5 M Tris-buffer which is known to remove assembly proteins (AP). Immunoblotting of GLUT4 and clathrin against specific antibodies showed that GLUT-4 and clathrin were co-solubilized up to 84.6% and 82.7% respectively by wash with a high pH buffer and 1% Tx-100. When the membrane was pre-washed with a high pH buffer and 0.5 M Tris solution, GLUT4 and clathrin were not solubilized further suggesting that GLUT4 molecules are in molecular association with clathrin, AP and/or other extrinsic membrane proteins in plasma membrane and the formation of clathrin-coated structures might be involved in insulin stimulated glucose transporter translocation mechanism.

• 대한의생명과학회지
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• 제7권4호
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• pp.161-166
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• 2001

Most mammalian cells take up glucose by passive transport proteins in the plasma membranes. The best known of these proteins is the human erythrocyte glucose transporter, GLUT1. High levels of heterologous expression far the transporter are necessary for the investigation of its three-dimensional structure by crystallization. To achieve this, the baculovirus expression system has become popular choice. However, Spodoptera frugiperda Clone 9 (Sf9) cells, which are commonly employed as the host permissive cell line to support baculovirus replication and protein synthesis, grow well on TC-100 medium that contains 0.1% D-glucose as the major carbon source, suggesting the presence of endogenous glucose transporters. Furthermore, very little is known of the endogenous transporters properties of Sf9 cells. Therefore, human GLUT1 antibodies would play an important role for characterization of the GLUT1 expressed in insect cell. However, the successful use of such antibodies for characterization of GLUT1 expression m insect cells relies upon their specificity for the human protein and lack of cross-reaction with endogenous transporters. It is therefore important to determine the potential cross-reactivity of the antibodies with the endogenous insect cell glucose transporters. In the present study, the potential cross-reactivity of the human GLUT1 antibodies with the endogenous insect cell glucose transporters was examined by Western blotting. Neither the antibodies against intact GLUT1 nor those against the C-terminus labelled any band migrating in the region expected fur a protein of M$_r$ comparable to GLUT1, whereas these antibodies specifically recognized the human GLUT1. Specificity of the human GLUT1 antibodies tested was also shown by cross-reaction with the GLUT1 expressed in insect cells. In addition, the insect cell glucose transporter was found to have very low affinity for cytochalasin B, a potent inhibitor of human erythrocyte glucose transporter.

• 생약학회지
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• 제39권3호
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• pp.228-232
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• 2008

Antidiabetic effects of an aqueous and solvent extract prepared from the root, stem and fruit parts of Acanthopanax senticosus, were investigated in experimental Streptozotocin (STZ)-induced diabetic rats model. The n-butanol and water extracts of A. senticosus were orally administrated once a day for 6 days. The n-butanol extracts of fruit (FB) showed highest efficiency than other groups (water extracts of stem, root and fruit; butanol extracts of stem, root) on serum glucose values in the STZ-induced diabetic rats. We have studied gene expression of glucose transporter genes in C2C12 skeletal muscle cell line during differentiation treated by the n-butanol and water extracts of A. senticosus, SW, RW, FW, SB, RB and FB. The GLUT4 gene was high expressed by FB treatment. These findings suggest that FB of A. senticosus have GLUT4 gene expression activity for glucose homeostasis and may have beneficial effects on blood glucose lowering in the diabetic patients.

• 운동영양학회지
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• 제13권1호
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• pp.1-7
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• 2009

It has been shown that both caloric restriction and exercise, enhances glucose uptake through translocation of GLUT-4 protein. It remains unclear how exercise and caloric restriction affect the changes in VAMP (vesicle-associated membrane protein) in skeletal muscle and GLUT-2 in liver. This study investigated the effects of exercise training and caloric restriction on the expressions of glucose transport relating proteins in muscle and liver tissues in diabetic rats. Forty male Sprague-Dawley rats (250±10 g; 8 week in age) were assigned equally to four different groups; control (C), exercise only (E), dietary restriction only (D) and dietary restriction and exercise (DE). Daily food consumption was monitored to establish baseline intake. Both C and E groups consumed baseline food intake while D and DE groups were provided with only 60% of baseline total food intake. Forty-eight hours after intraperitoneal injection of STZ (50 mg/kg), diabetes was confirmed (8-hr fasting blood glucose levels ≥300 mg/dl). Rats in the E and DE groups exercised on a motorized treadmill for 30 min/d, 5 days/week for 4 weeks (5 min running at 3 m/min, 0% grade; 8 m/min for the next 5min, and then 15 m/min for 20 min). Rats were sacrificed 48 hrs after the last bout of exercise. Soleus muscle and liver were extracted to analyze for GLUT-4, VAMP-2, and GLUT-2, respectively. All variables were analyzed using the Western Blotting technique. All values were expressed as optical volume measured by optical density. A Two-way ANOVA was used to examine the difference between groups and applied Duncan's test for post-hoc. No significant differences in GLUT-2 expression were found among groups. However, E (280133±13228 arbitrary units{AU}) and DE (268833±14424 AU) groups showed significantly higher (p<.001) levels of GLUT-4 as compared with C (34461±2099 AU) and D groups (27847±703 AU). VAMP-2 protein expression increased (p<.001) in E (184137±7803 AU) and DE (189800±10856 AU) groups as compared to C (74201±8296AU) and D (72967±863 AU) groups. These results suggest that either exercise with or without caloric restriction increases the up-regulation of GLUT-4 and VAMP-2 in skeletal muscle of diabetic rats. However, GLUT-2 protein in liver was not affected by either exercise or exercise with caloric restriction.

• 생명과학회지
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• 제21권11호
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• pp.1532-1540
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• 2011

본 연구는 7주령의 S D계 흰쥐를 이용하여 12주 동안의 사다리 오르기 저항성 운동 수행 후 가자미근과 비복근 내 GLUT-4 발현량 및 LDH 동위효소들의 변화를 측정하여 당 대사 및 젖산 기전에 대한 연구로 다음과 같은 결론을 얻었다. 12주간의 사다리 오르기 저항성 운동은 체중감소에 효과적인 것으로 나타났으며, 가자미근 및 비복근 조직 GLUT-4 단백질 발현을 유의하게 증가시키는 것으로 나타났다. 또한 가자미근 및 비복근 조직 LDHA B-type 동위효소의 발현을 유의하게 증가시키는 것으로 나타났다. 본 연구의 결과를 종합해 볼 때 12주간의 저항성훈련은 체중의 감소와 골격근 내 GLUT-4의 증가 그리고 LDH A4 동위효소를 제외한 LDH B-type 동위 효소의 증가와 같은 신체조성의 균형과 당대사능력 및 미토콘드리아의 기능 개선에 영향을 미치는 것으로 사료된다. 추후 연구에서는 휴식시간이나 운동 강도의 차이와 근형태별에 따른 유 무산소적 저항훈련 프로그램의 효과에 따른 다양한 연구가 실시되어야 할 것으로 생각된다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권4호
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• pp.1823-1829
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• 2014

Aims: Much evidence suggests that increased glucose metabolism in tumor cells might contribute to the development of acquired chemoresistance. However, the molecular mechanisms are not fully clear. Therefore, we investigated a possible correlation of mRNA expression of HIF-$1{\alpha}$ and GLUT1 with chemoresistance in acute myeloid leukemia (AML). Methods: Bone marrow samples were obtained from newly diagnosed and relapsed AML (M3 exclusion) cases. RNA interference with short hairpin RNA (shRNA) was used to stably silence GLUT1 or HIF-$1{\alpha}$ gene expression in an AML cell line and HIF-$1{\alpha}$ and GLUT1 mRNA expression was measured by real-time quantitative polymerase chain reaction assay (qPCR). Results: High levels of HIF-$1{\alpha}$ and GLUT1 were associated with poor responsiveness to chemotherapy in AML. Down-regulation of the expression of GLUT1 by RNA interference obviously sensitized drug-resistant HL-60/ADR cells to adriamycin (ADR) in vitro, comparable with RNA interference for the HIF-$1{\alpha}$ gene. Conclusions: Our data revealed that over-expression of HIF-$1{\alpha}$ and GLUT1 might play a role in the chemoresistance of AML. GLUT1 might be a potential target to reverse such drug resistance.