ABSTRACT
Glucose transporter 4 (GLUT4), a major contributor to glucose transport in skeletal muscle, is closely related to diabetic treatment. Exercise regulates apparently GLUT4 gene expression which produces many beneficial metabolic adaptations for diabetic patients. Study has shown that both AMPK (AMP-activated protein kinase) and CaMK (calcium-calmodulin dependent protein kinase) signaling pathways are involved in regulation of exercise-induced GLUT4 gene expression in skeletal muscles, but the relationship between these two signaling pathways in regulating the GLUT4 gene is unclear. The purpose of the following study was to investigate the relationship of these two pathways in Caffeine- and AICAR-stimulated skeletal muscle cells GLUT4 gene expression. Muscle contractile activity results in increases in both cytosolic Ca2+ and AMPK activity. To mimic this response, primary cultured rat skeletal muscle cells were treated with Caffeine to raise cytosolic Ca2+ and with AICAR to activate AMPK. The muscle cells were divided into different groups (Control, AICAR, Caffeine, AICAR/Caffeine, Caffeine +Compound C, AICAR/Caffeine +Compound C, AICAR +KN93, AICAR/Caffeine + KN93), which were used for experiments of stimulation by AICAR and Caffeine, inhibition by AMPK inhibitor, Compound C and CaMK inhibitor, KN93 respectively. The results showed that both AICAR and Caffeine induced about 2- and 3-fold increases respectively (P
ABSTRACT
Objective To investigate the mechanism of Chinese herbal medicine compound Tang Mai Ping (TMP) capsule to type 2 diabet in rats. Methods The models of type 2 diabetic rats were established by injecting lower dosage of streptozotocin (STZ, 35 mg/kg) to belly, and fed high sucrose and high fat diet. Modle rats were randomly divided into model group, TMP group, and Erjiashuanggu (EJS) group, at the same time normal control. The content of plasma insulin was detected by radio-immunicy, mRNA expressing of frame muscle of Glucose Transporter 4 (GluT4) gene was detected with hyvirdism in situ. Results After built model, levels of insulin were obviously ascended in rats, but the expression of GluT4 mRNA lower significantly (P
ABSTRACT
Objective To investigate the effect of RBP on 3T3-L1 adipocyte differentiation,lipid metabolism and glucose transporter 4(GLUT-4)gene expression.Methods We constructed an expression vector for rat resistin gene and transfected it into 3T3-L1 adipocytes.RBP was added to the medium of 3T3-L1 adipocytes or resistin-overexpressing adipocytes on day 0 of differentiation.Cell differentiation and lipid accumulation were determined by oil red O staining.The mRNA expressions of differentiation marker genes(pref-1,C/EBP?,FAS)and GLUT-4 gene were evaluated by RT-PCR.Triglyceride(TG)and free fatty acids(FFAs)in adipocytes were measured by colorimetric kit.Results(1)When 10-12mol/L RBP was applied,the percent of living cells was high and the shape was unchanged.(2)RBP had no effect on the differentiation of normal adipocytes,but significantly decreased the number of lipid droplets in resistin-overexpressing adipocytes without affecting the lipid droplets-presenting day.(3)C/EBP? and FAS expressions in resistin-overexpressing adipocytes were down-regulated after RBP was applied,without changing their expressions in normal adipocytes.(4)RBP had no effect on the cellular TG and FFAs levels in normal cells,whereas it can significantly decrease the levels in resistin-overexpressing adipocytes.(5)There was no difference in the expression of GLUT-4 gene between 3T3-L1 adipocytes and RBP-applied cells.Conclusions(1)RBP has no effect on the cell differentiation and lipid metabolism in normal 3T3-L1 adipocytes.(2)RBP can inhibit the cell differentiation and lipid metabolism of resistin-overexpressing 3T3-L1 cells.(3)RBP has no effect on the expression of GLUT-4 gene.