Effects Of Sodium Tungstate On Glucose Metabolism In Adipocytes

Objective:To observe the direct effects of sodium tungstate on glucose metabolism in adipocytes in vitro and study the potential mechanism.Methods:After 3T3-L1 preadipocytes were grown and differentiated into adipocytes,the cells were divided into experimental group and control group.Experimental groups were treated with high glucose DMEM medium which containing various concentration of sodium tungstate(150μmol/L,300μmol/L,500μmol/L,700μmol/L),While control group were treated with sodium-tungstate-free high glucose DMEM.All the cells were incubated for 48 hours,then amount of glucose disappearance from the culture medium was determined as glucose consumption of the cells.The uptake of 2-deoxy-[~3H]-D-glucose was used to determine glucose transport.The expression of GLUT-4 mRNA and PPAR_γmRNA were determined by semi-quantitative RT-PCR.The vitality and amount of the cells were estimated by MTT assay.Apoptotic cell and cell cycle were identified by PI staining,then quantitated by flow cytometry.Results:After experimental group were treated with 150μmol/L～700μmol/L sodium tungstate,glucose consumption were increased by 45%,79%,112%,144%respectively(P＜0.01),and with a concentration dependent-effect,glucose transport were increased by 35%,76%,89%, 91%respectively((P＜0.01).Since glucose transport were similar between 500～700μmol/L concentration(P＞0.05),It indicates that glucose transport intends to be maximum when sodium tungstate concentration achieve 500μmol/L～700μmol/L.Using semi-quantitative RT-PCR techniques,it was found that sodium tungstate upregulated GLUT-4 mRNA expression and PPAR_γmRNA expression in adipocytes(P＜0.05).The result of MTT assay indicated that vitality and amount of the cells were not siginificant different between experimental group and control group(P＞0.05),flow cytometric analysis revealed that apoptotic rate and cycle of the cells were unchanged when compared with control group(P＞0.05). Conclusion Sodium tungstate promote glucose metabolism of adipocytes by up-regulates glucose transporter 4(GLUT-4)mRNA expression and PPAR_γmRNA expression,while sodium tungstate has no significant effect on apoptotic rate and cycle of the cells.