• Journal of Life Science
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• v.31 no.8
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• pp.729-735
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• 2021

Type 2 diabetes occurs when there is an abnormality in the tissue's ability to absorb glucose. Glucose uptake and metabolism by insulin are the basic mechanisms that maintain blood sugar. Glucose uptake goes through various signaling steps initiated by the binding of insulin to receptors on the cell surface. In line with the foregoing, the purpose of this study was to investigate the effect of 2,7-phloroglucinol-6,6-bieckol (PHB), an active compound isolated from Ecklonia cava, on glucose uptake in 3T3-L1 adipocytes. Notably, PHB increased glucose uptake in a dose-dependent manner owing to the enhanced glucose transporter type 4 (GLUT4) expression in the plasma membrane of 3T3-L1 adipocytes. These effects of PHB were attributed to the phosphorylation of insulin receptor substrate-1 and protein kinase B (PKB or AKT), as well as to the phosphoinositide 3-kinase (PI3K) activation in the insulin signaling pathway. PHB also stimulated 5' AMP-activated protein kinase (AMPK) phosphorylation and activation. The phosphorylation and activation of the PI3K/AKT and AMPK pathways by PHB were identified using wortmannin (a PI3K inhibitor) and compound C (an AMPK inhibitor). In this study, we showed that PHB can increase glucose uptake in 3T3-L1 adipocytes by promoting GLUT4 translocation to the plasma membrane via the PI3K and AMPK pathways. The results indicate that PHB may help improve insulin sensitivity.

• The Journal of Korean Medicine
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• v.20 no.2
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• pp.108-120
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• 1999

In this study, body weight levels of glucose, insulin and triglyceride in blood and glucosidase activity of the small intestine were investigated to determine the effect of Sangbaegpitang and Supungsungiwhan on the glucose metabolism of db/db mice. The GLUT4 mRNA of muscle tissue and the Acetyl CoA Carboxylase and the activation rate of GLUT2 mRNA of liver tissue were measured by the reverse transcription-polymerase chain reaction method and by the vitro transcription. The results were obtained as follows: 1. In the Sangbaegpitang administration group, (1) The level of triglyceride was decreased significantly and the glucosidase activity of the small intestine was inhibited remarkably, (2) The amounts of the GLUT4 mRNA in muscle tissue and Acetyl CoA Carboxylase mRNA in liver tissue were increased significantly. (3) Though glucose level in both fasting and non-fasting, were decreased and the insulin level in blood was increased, the results showed no statistical significance. 2. In the Supungsungiwhan administration group, (1) The levels of glucose and triglyceride were decreased significantly in the blood of non-fasting animals. (2) The glucosidase activity of small intestine was inhibited markedly and the amounts of GLUT4 mRNA of muscle tissue and GLUT2 mRNA of liver tissue were increased significantly. (3) The glucose levels in the fasting group were reduced, while insulin level was increased but showed no statistical significance, Based on the above results, our conclusions are as follows: Sangbaegpitang & Supungsungiwhan are thought to be capable of inhibiting the activity glucosidase, the enzyme which influences carbohydrate metabolism in the small intestine of db/db mice(the experimental diabetic model) and delaying the absorption of carbohydrate, thus proving effective on inhibiting the increase of non-fasting glucose level effectively. Futhermore Sangbaegpitang and Supungsungiwhan are though: to be capable of preventing the composition of free fatty acids by restoring the production of GLUT4 mRNA of muscle tissues and GLUT2 mRNA of liver tissues. Those results suggests that above prescriptions can be applied to non-insulin dependent diabetes mellitus in order to improve insulin resistance.

• The Korean Journal of Nuclear Medicine
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• v.36 no.2
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• pp.110-120
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• 2002

To clarify the difference in glucose uptake between human cancer cells and monocytes, we studied $[^{18}F]$ fluorodeoxyglucose (FDG) uptake in three human colon cancer cell lines (SNU-C2A, SNU-C4, SNU-C5), one human lung cancer cell line (NCI-H522), and human peripheral blood monocytes. The FDG uptake of both cancer cells and monocytes was increased in glucose-free medium, but decreased in the medium containing 16.7 mM glucose (hyperglycemic). The level of Glut1 mRNA decreased in human colon cancer cells and NCI-H522 under hyperglycemic condition. Glut1 protein expression was also decreased in the four human cancer cell lines under hyperglycemic condition, whereas it was consistently undetectable in monocytes. SNU-C2A, SNU-C4 and NCI-H522 showed a similar level of hexokinase activity (7.5 - 10.8 mU/mg), while SNU-C5 and monocytes showed lower range of hexokinase activity (4.3 - 6.5 mU/mg). These data suggest that glucose uptake is regulated by different mechanisms in human cancer cells and monocytes.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.1 no.1
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• pp.23-27
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• 2001

Fanconi-Bickel Syndrome (FBS) is a rare autosomal recessive disorder of carbohydrate metabolism recently demonstrated to be caused by mutations in the GLUT 2 gene for the glucose transporter protein 2 expressed in liver, pancreas, intestine, and kidney. This disease is characterized by hepatorenal glycogen accumulation, both fasting hypoglycemia as well as postprandial hyperglycemia and hyperglactosemia, and generalized proximal renal tubular dysfunctions. We report the first Korean patient with FBS diagnosed based on clinical manifestations and identification of a novel mutation in the GLUT 2 gene. She was initially diagnosed having a neonatal diabetes mellitus due to hyperglycemia and glycosuria at 3 days after birth. In addition, newborn screening for galactosemia revealed hypergalactosemia. Thereafter, she has been managed with lactose free milk, insulin therapy. However, she failed to grow and her liver has been progressively enlarging. Her liver functions were progressively deteriorated with increased prothrombin time. Liver biopsy done at age 9 months indicated micronodular cirrhosis with marked fatty changes. She succubmed to hepatic failiure with pneumonia at 10 months of age. Laboratory tests indicated she had generalized proximal renal tubular dysfuctions; renal tubular acidosis, hypophosphatemic rickets, and generalized aminoaciduria. Given aforementioned findings, the diagnosis of FBS was appreciated at age of 2 months. The DNA sequencing analysis of the GLUT 2 gene using her genomic DNA showed a novel mutation at 5th codon; Lysine5 Stop (K5X).

• International Journal of Oral Biology
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• v.45 no.3
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• pp.115-125
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• 2020

Resveratrol has been reported to exert anticancer activity via modulation of multiple pathways and genes. In this study, we examined the effect of resveratrol on YD-10B human oral squamous cell carcinoma cells and its molecular mechanisms of action. We found that resveratrol inhibited the proliferation of YD-10B cells in a dose- and time-dependent manner. The suppressive effect of resveratrol was accompanied by a reduction in Bmi-1 gene expression. We observed that silencing the Bmi-1 gene by small interfering RNA effectively downregulated the levels of GLUT1 mRNA and protein, which were also repressed by resveratrol. Bmi-1 silencing increased the number of YD-10B cells in S-phase arrest by approximately 2.3-fold compared with the control. In conclusion, the results of the present study demonstrate, for the first time, that resveratrol suppresses Bmi-1-mediated GLUT1 expression in human oral squamous cell carcinoma cells and suggest that the specific molecular targeting of Bmi-1 and/or GLUT1 expression can be combined with a chemotherapeutic strategy to improve the response of oral cancer cells to resveratrol.

• Journal of Life Science
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• v.21 no.3
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• pp.435-443
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• 2011

The purpose of this study is to identify the effects of exercise training [ET, 10~18 m/min (speed), 20~30 min (exercise duration)/a day for 5 day/wk, 6 wk) on PGC-$1{\alpha}$, GLUT-1, Tfam, Cu,Zn-SOD and Mn-SOD proteins in brain of STZ-induced diabetic rats. The male Sprague-Dawley (SD) rats were single-injected intraperitoneally with 50mg/kg of streptozotocin (STZ) to produce STZ-induced diabetic rats. Rats were divided into 3 experimental groups with 8 rats in each group, as follows: (1) non-STZ group (n=8), (2) STZ-CON group (n=8), (3) STZ-EXE group (n=8). The results of this study suggest that i) serum glucose level was significantly reduced in STZ-EXE group compared with STZ-CON group (p<0.05), ii) PGC-$1{\alpha}$ (p<0.001), mtPGC-$1{\alpha}$ (p<0.001), GLUT-1 (p<0.001), and mtTfam (p<0.001) proteins in brain of STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group, iii) Cu,Zn-SOD (p<0.001) and Mn-SOD (p<0.01) proteins in the STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group. In conclusion, the findings of the present study reveal that treadmill exercise training increases brain GLUT-1 protein level possibly through up-regulation of PGC-$1{\alpha}$ and Tfam proteins which represent key regulatory components of stimulation of brain mitochondrial biogenesis. In addition, treadmill exercise training may prevent oxidative stress by up-regulation of Cu,Zn-SOD and Mn-SOD proteins in the STZ-induced diabetic rats.

• The Korean Journal of Nuclear Medicine
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• v.31 no.3
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• pp.381-387
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• 1997

Cancer tissues are characterized by increased glucose uptake. $^{18}F$-fluorodeoxyglucose(FDG), a glucose analogue is used for the diagnosis of cancer in PET studies. This study was aimed to compare the glucose uptake and glucose transporter 1(GLUT1) expression in various human colon cancer cells. We measured FDG uptake by cell retention study and expression of GLUT1 using Western blotting. Human colon cancer cells, SNU-C2A, SNU-C4 and SNU-C5, were used. The cells were incubated with $1{\mu}Ci/ml$ of FDG in HEPES-buffered saline for one hour. The FDG uptake of SNU-C2A, SNU-C4 and SNU-C5 were $16.8{\pm}1.36,\;12.3{\pm}5.55$ and $61.0{\pm}2.17cpm/{\mu}g$ of protein, respectively. Dose-response and time-course studies represent that FDG uptake of cancer cells were dose dependent and time dependent. The rate of FDG uptake of SNU-C2A, SNU-C4 and SNU-C5 were $0.29{\pm}0.03,\;0.21{\pm}0.09$ and $1.07{\pm}0.07cpm/min/{\mu}g$ of protein, respectively. Western blot analysis showed that the GLUT1 expression of SNU-C5 was significantly higher than those of SNU-C2A and SNU-C4. These results represent that FDG uptake into human colon cancer cells are different from each other. In addition, FDG uptake and expression of GLUT1 are closely related in human colon cancer cells.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.440-447
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• 2003

Up until today, the key to contouring has been resumed in these two alternatives, either limiting the adipocyte storing capacity by modulating lipogenesis, or by stimulating lipolysis to eliminate adipocyte lipid content. Another interesting way could be the regulation of adipocyte differentiation. In this work, we have evaluated the effect of a brown algal extract of Sphacelaria scoparia (SSE) on the differentiation of pre-adipocytes into adipocytes. A pre-adipocyte line (3T3-L 1) was used. The differentiation was evaluated by the measure of produced lipids thanks to red oil coloration and spectrophotometry, and also by the expression of adipocyte differentiation markers: enzymes such as fatty acid synthase (FAS) and stearoyl CoA desaturase (SCD), or membrane proteins such as glucose transporters (GLUT -4) and fatty acid transporters (FAT) expressed on the surface of human adipocytes. These genes are under control of two transcription factors: CAAT-enhancer binding protein (c/EBP alpha) and sterol response element binding protein (SREBP1). All these markers were analysed at different stages of differentiation by RT -PCR. Sphacelaria extract (SSE) inhibits pre-adipocytes differentiating into adipocytes following a dose-dependant relation, using a kinetics similar to retinoic acid. It decreases the expression of mRNA specific to FAS, FAT, GLUT -4, SCD1, c/EBP alpha and SREBP1. Moreover, SSE regulated on collagen 1 and collagen 4 expression. A stimulation of collagen 1 was also measured in human skin fibroblasts. Thus, SSE performs as a genuine differentiation inhibitor and not only as a lipogenesis inhibitor, and could be used in slimming products.

• Reproductive and Developmental Biology
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• v.39 no.4
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• pp.97-104
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• 2015

Glucose is universal and essential fuel of energy metabolism and in the synthesis pathways of all mammalian cells. Glucose is the one of the major precursors of lactose synthesis using glycolysis result in producing milk fat and protein. During the milk fat synthesis, lipoprotein lipase (LPL) and CD36 are required for glucose uptake. Various morecules such as acyl-CoA synthetase 1 (ACSL1) activity of acetyl-CoA synthetase 2 (ACSS2), ACACA, FASN AGPAT6, GPAM, LPIN1 are closely related with milk fat synthesis. Additionally, glucose plays a major role for synthesizing lactose. Activations of lactose synthesize enzymes such as membranebound enzyme, beta-1,4-galactosyl transferase (B4GALT), glucose-6-phosphate dehydrogenase (G6PD) are changed by concentration of glucose in blood resulting change of amount of lactose production. Glucose transporters are a wide group of membrane proteins that facilitate the transport of glucose over a plasma membrane. There are 2 types of glucose transporters which consisted facilitative glucose transporters (GLUT); and sodium-dependent transport, mediated by the Na+/glucose cotransporters (SGLT). Among them, GLUT1, GLUT8, GLUT12, SGLT1, SGLT2 are main glucose transporters which involved in mammary gland development and milk synthesis. However, more studies are required for revealing clear mechanism and function of other unknown genes and transporters. Therefore, understanding of the mechanisms of glucose usage and its regulation in mammary gland is very essential for enhancing the glucose utilization in the mammary gland and improving dairy productivity and efficiency.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.11
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• pp.1690-1694
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• 2003

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 growth factors and gut regulatory peptides with insulin, in vitro experiment was conducted with HC11 cells. All the growth factor alone and the combinations of growth factors significantly (p<0.05) increased in glucose uptake. Insulin, EGF and IGF-1 exhibited a stimulation of glucose uptake for at least 24 h. Furthermore, the highest (p<0.05) synergistic effect was shown in EGF plus IGF-1 and the second synergistic effect in insulin plus EGF while no synergistic effect was found between insulin and IGF-1. However, the gut regulatory peptides neither potentiated nor inhibited the action of insulin on glucose uptake. Although growth factors did not modulates glucose uptake via increasing the rate of translation of the GLUT1 protein, RT-PCR analysis indicated that the growth factors significantly (p<0.05) increased the expression of GLUT1. The growth factors are therefore shown to be capable of modulating glucose uptake by transcription level with insulin in HC 11 cells.