• Asian Pacific Journal of Cancer Prevention
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• v.15 no.10
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• pp.4245-4250
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• 2014

Emerging evidence has suggested that glycolysis is enhanced in cancer-associated fibroblasts (CAF), and miR-186 is downregulated during the CAF formation. However, it is not clear whether miR-186 is involved in the regulation of glycolysis and what the role of miR-186 plays during the CAF formation. In this study, quantitative PCR analysises show miR-186 is downregulated during the CAF formation. Moreover, miR-186 targets the 3' UTR of Glut1, and its overexpression results in the degradation of Glut1 mRNA, which eventually reduces the level of Glut1 protein. On the other hand, knockdown of miR-186 increased the expression of Glut1. Both time course and dose response experiments also demonstrated that the protein and mRNA levels of Glut1 increase during CAF formation, according to Western blot and quantitative PCR analyses, respectively. Most importantly, besides the regulation on cell cycle progression, miR-186 regulates glucose uptake and lactate production which is mediated by Glut1. These observations suggest that miR-186 plays important roles in glycolysis regulation as well as cell cycle checkpoint activation.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.859-866
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• 2007

The main objective of this study was to investigate the effects of exercise on serum insulin and leptin levels and GLUT-4 and VAMP-2 in skeletal muscles from the pregnant rats. F344 rats were randomly divided into four groups (n = 15 in each group): control group (CG), pregnant group (PG), pregnant running group (PR), and pregnant swimming group (PS). From the 15th day of pregnancy, animals in the running group were forced to run on treadmill for 30 min with a light intensity, while those in the swimming group were forced to swim in swimming pool for 10 min once a day for 6 consecutive days. The present result demonstrated that in pregnant rat group, serum insulin levels significantly in-creased and leptin levels significantly decreased. Skeletal GLUT-4 and VAMP-2 protein expression was significantly decreased in pregnant rats compared to non-pregnant rats. However, matenal running during gestational period alleviated pregnancy-induced changes in plasma insulin and leptin levels, and it significantly enhanced skeletal GLUT-4 and VAMP-2 protein expression. From those results, it can be suggested that running exercise during gestational period may improve glycemic control by up-regulating GLUT-4 and VAMP-2 protein expression.

• The Korean Journal of Physiology
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• v.25 no.2
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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.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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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.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.450-455
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• 2004

A reducing glucose-carrying polymer, called poly [3-O-(4'-vinylbenzyl)-D-glucose］(PVG), was interacted with HepG2 cells including a type-l glucose transporter (GLUT-1) on the cell membrane. The cooperative interaction between a number of GLUT-1s and a number of reducing 3-O-methyl-D-glucose moieties on the PVG polymer chain was found to be responsible for the increase in the interaction with HepG2 cells. The affinity between the cells and the PVG was studied using RITC-labeled glycopolymers. The specific interaction between the GLUT-1 on HepG2 cells and the PVG polymer carrying reducing glucose moieties was suppressed by the inhibitors, phloretin, phloridzin, and cytochalasin B. Direct observation by confocal laser microscopy with the use of RITC-labeled PVG and pretreatment of HepG2 cells with the inhibitors demonstrated that the cells interacted with the soluble form of the PVG polymer via GLUT-1, while fluorescence labeling of the cell surface was prevented after pretreatment with the inhibitors of GLUT-1.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1210-1214
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• 2002

The large and rapid changes of glucose utilization in lactating mammary tissue in response to changes in nutritional state must be largely related by external signal of insulin. This also must be related with the quantity and composition of the diet in vivo. To characterize the mode of gut extract protein with insulin, in vitro experiment was conducted with HC11 cells. The gut extract protein has not only the same effect as insulin alone but also the synergistic effect with insulin in 2-Deoxy[3H] glucose uptake. Although the gut extract did not modulates glucose uptake via increasing the rate of translation of the GLUT1 protein, northern blot analysis indicated that the gut extract protein increased the expression of GLUT1 mRNA by a threefold and also there was a dose-dependent increase in the expression of GLUT1 mRNA. The gut extract protein is therefore shown to be capable of modulating glucose uptake by transcription level with insulin in HC 11 cells.

• Journal of Nutrition and Health
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• v.47 no.3
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• pp.167-175
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• 2014

Purpose: Previous studies have shown that treatment with Smilax china L. leaf extract (SCLE) produces antidiabetic effects due to ${\alpha}$-glucosidase inhibition. In this study, we examined the mechanism underlying these antidiabetic effects by examining glucose uptake in HepG2 cells cultured with SCLE. Methods: Glucose uptake and glucokinase activity were examined using an assay kit. Expression of glucose transporter (GLUT)-2, GLUT-4, and HNF-$1{\alpha}$ was measured by RT-PCR or western blot. Results: Treatment with SCLE resulted in enhanced glucose uptake in HepG2 cells, and this effect was especially pronounced when cells were cultured in an insulin-free medium. SCLE induced an increase in expression of GLUT-2 but not GLUT-4. The increase in the levels of HNF-$1{\alpha}$, a GLUT-2 transcription factor, in total protein extract and nuclear fraction suggest that the effects of SCLE may occur at the level of GLUT-2 transcription. In addition, by measuring the change in glucokinase activity following SCLE treatment, we confirmed that SCLE stimulates glucose utilization by direct activation of this enzyme. Conclusion: These results demonstrate that the potential antidiabetic activity of SCLE is due at least in part to stimulation of glucose uptake and an increase in glucokinase activity, and that SCLE-stimulated glucose uptake is mediated through enhancement of GLUT-2 expression by inducing expression of its transcription factor, HNF-$1{\alpha}$.

• Korean Journal of Exercise Nutrition
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• v.13 no.2
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• pp.131-140
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• 2009

The aim of this study was to investigate the expression of PPAR-α, -β/δ, -γ, PGC-1α, GLUT-4 and p-AMPK-α₂ protein in the skeletal muscle of diabetic induced-rats by endurance training combined with rosiglitazone. The expression of PPAR-α, -β/δ, -γ, PGC-1α, GLUT-4 and p-AMPK-α₂ protein in red and white gastrocnemius by western blotting. The body weight was higher in diabetic induced-rats compared to the normal rats and after the treatment of exercise combined with rosiglitazone was significantly reduced in the all group. The levels of blood glucose was higher in diabetic induced-rats compared to the normal rats and after the treatment of exercise combined with rosiglitazone was significantly reduced in the all group. The expression of PPAR-α, -γ, PGC-1α in skeletal muscle of diabetic induced-rats were increased all groups and increased significantly in the group with exercise combined with rosiglitazone. The expression of GLUT-4 and p-AMPK-α₂ protein in the skeletal muscle of diabetic induced-rats were increased all groups and increased significantly in the group with exercise combined with rosiglitazoneI. These results suggest that exercise training and rosiglitazone may act as complementary therapies for the treatment of insulin rasistance.

• BMB Reports
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• v.30 no.4
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• pp.240-245
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• 1997

Interactions between ganglioside $G_{M3}$ and glucose transporter, GLUT1 were studied by measuring the effect of $G_{M3}$ on steady-state and time-resolved fluorescence of purified GLUT1 in synthetic lipids and on the 3-O-methylglucose uptake by human erythrocytes. The intrinsic tryptophan fluorescence showed a GLUT 1 emission maximum of 335 nm, and increased in the presence of $G_{M3}$ by 12% without shifting the emission maximum, The fluorescence lifetimes of intrinsic tryptophan on GLUT1 consisted of a long component of 7.8 ns and a short component of 2,3 ns and $G_{M3}$ increased both lifetime components. Lifetime components were quenched by acrylamide and KI. Acrylarnide-mduced quenching of long-lifetime components was partly recovered by $G_{M3}$ However. KI-induccd quenching of short- and long-lifetime components was not rescued by $G_{M3}$. The anisotropy of 1.6-diphenyl-1.3.5-hexatriene (DPH)-probed dimyristoylphosphatidylcholine (DMPC) model membrane was also increased with $G_{M3}$ incorporation, The transport rate of 3-O-methylglucose increased by 20% with $G_{M3}$ incorporation on the erythrocytes, Therefore, $G_{M3}$ altered the environment of lipid membrane and induced the conformational change of GLUT1.

• YAKHAK HOEJI
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• v.42 no.6
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• pp.589-597
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• 1998

Effects of Mori Folium Ethanol Soluble Fraction (MFESF) on mRNA expression of glucose transporters, acetyl-CoA carboxylase (ACC) and leptin were examined in db/db mice. 500 and 1000mg/kg dose for MFESF (designated by SY 500 and SY 1000, respectively) and 5mg/kg dose for acarbose were administered for 6 weeks. Quantitations of glucose transporters (GLUT-2 and GLUT-4), ACC and leptin mRNA were performed by RT-PCR and in vitro transcription with co-amplification of rat ${\beta}$-actin gene as an internal standard. Muscular GLUT-4 mRNA expression in MFESF-treated groups were increased dose dependently. On the other hand, MFESF caused the GLLT-4 and leptin mRNA expressions in adipose tissue to decrease dose dependently, which means that triglyceride synthesis in adipocytes might be decreased and consequently signals adipocytes to inhibit the synthesis and release of leptin. Hepatic ACC mRNA expression in MFESF-treated groups was also decreased. and this may result in lowering of serum triiglyceride level. In contrast, liver GLUT-2 mRNA expressions in MFESF-treated and acarbose groups were increased. Higher rate of glucose uptake into hepatocytes is known to inhibit a phosphoenolpyruvate carboxykinase (PEPCK)-catalyzed reaction, which is a rate-limiting step in gluconeogenesis.