• The Korean Journal of Physiology
• /
• v.25 no.2
• /
• pp.115-123
• /
• 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.

• Reproductive and Developmental Biology
• /
• v.39 no.4
• /
• pp.97-104
• /
• 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
• /
• v.23 no.9
• /
• pp.1159-1165
• /
• 2010

Glucose is the main energy source for mammalian cells and its absorption is co-mediated by two different families of glucose transporters, sodium/glucose co-transporters (SGLTs) and facilitative glucose transporters (GLUTs). Here, we report the cloning and tissue distribution of porcine GLUT2. The GLUT2 was cloned by RACE and its cDNA was 2,051 bp long (GenBank accession no. EF140874). An AAATAA consensus sequence at nucleotide positions 1936-1941 was located upstream of the poly $(A)^+$ tail. Open reading frame analysis suggested that porcine GLUT2 contained 524 amino acids, with molecular weight of 57 kDa. The amino acid sequence of porcine GLUT2 was 87% and 79.4% identical with human and mouse GLUT2, respectively. GLUT2 mRNA was detected at highest level in porcine liver, at moderate levels in the small intestine and kidney, and at low levels in the brain, lung, muscle and heart. In the small intestine, the highest level was in the jejunum. In conclusion, the mRNA expression of GLUT2 was not only differentially regulated by age, but also differentially distributed along the small intestine of piglets, which may be related to availability of different intestinal luminal substrate concentrations resulting from different food sources and digestibility.

• Biomolecules & Therapeutics
• /
• v.12 no.4
• /
• pp.250-256
• /
• 2004

Cordyceps possesses numerous health-promoting ingredients including hypoglycemic agents. The mechanism for the reduction of circulatory sugar content, however, is still not fully understand. In this study, 4-beta acetoxyscirpendiol (ASD) was purified from the methanolic extracts from fruiting bodies of Paecilomyces tenuipes. Na+/Glucose transporter-1 (SGLT-1) was expressed in the Xenopus oocytes. The effect of ASD on the oocyte expressed SGLT-1 was analyzed utilizing the voltage clamp and 2-deoxy-D-glucose (2-DOG) uptake studies. ASD was shown to significantly inhibit SGLT-1 activity compared to the non-treated control in a dose- dependent manner. In the presense of its two derivatives (diacetoxyscirpenol or 15-acetoxyscirpendiol), SGLT-1 activity was greatly inhibited similarly as ASD. Between ASD derivatives, 15-acetoxyscirepenol showed inhibition equivalent to that of ASD while diacetoxyscirpenol did less degree of inhibition. Insummary , these results strongly indicate that ASD in P. tenuipes may serve as a functional substance in lowering blood sugar in the circulatory system. ASD and its derivatives can be utilized as inhibitors of SGLT-1.

• Journal of Medicine and Life Science
• /
• v.17 no.2
• /
• 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.

• Proceedings of the KSAR Conference
• /
• 2003.06a
• /
• pp.71-71
• /
• 2003

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a multifunctional cytokine that has been implicated in the regulation of pre-implantation embryo development across several species. The aim of this study was to determine the effects of mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) on development of porcine parthenotes and nuclear transferred embryos, and on their expression of implantation-related genes. In the presence of bovine serum albumin, mGM-CSF did not increase the percentage of oocytes that developed to the blastocyst stage and at day 7 did not increase oocyte cell number. Addition of 10 mM GM-CSF to protein-free culture medium significantly increased the compaction and blastocoel formation of 1- to 2-cell parthenotes and cloned embryos developing in vitro. However, cell number was not increased when they were cultured in the presence of GM-CSF. Semi-quantitative reverse transcripts polymerase chain reaction (RT-PCR) revealed that mGM-CSF enhances mRNA expression of the leukemia inhibitory factor receptor, but does not influence interleukin-6 or sodium/glucose co-transporter protein gene expression in blastocyst stage parthenotes. These results suggest that mGM-CSF may enhance viability of porcine embryos developing in vitro in a defined culture medium.