The relative abundance and subcellular distribution of the GLUT-1 and GLUT-4 glucose transporter isoforms were determined in basal and insulin-stimulated adipose cells from wheel cage exercise-trained rats and compared with both age-matched sedentary controls and young cell size-matched sedentary controls. Exercise training increased total estimated GLUT-4 by 67 and 54% compared with age-matched and young controls, respectively. Total estimated GLUT-1 per cell was not significantly different among the three groups.
View Article and Find Full Text PDFThe purpose of this study was to characterize an animal model of impaired glucose tolerance produced by streptozocin treatment of rats (45 mg/kg, intravenously [i.v.]) and selection of animals with plasma glucose concentrations less than 150 mg/dL.
View Article and Find Full Text PDFThe question of a long term regulatory role of insulin on adipocyte glucose transporter content was addressed using the differentiating or fully mature 3T3-F442A adipocytes. Glucose transport was measured in intact cells. Glucose transporter content in plasma membranes and low density microsomes (LDM) was assessed by cytochalasin B binding and Western analysis.
View Article and Find Full Text PDFThe purpose of this study was to simultaneously isolate skeletal muscle plasma and microsomal membranes from the hind limbs of male Sprague-Dawley rats perfused either in the absence or presence of 20 milliunits/ml insulin and to determine the effect of insulin on the number and distribution of glucose transporters in these membrane fractions. Insulin increased hind limb glucose uptake greater than 3-fold (2.4 +/- 0.
View Article and Find Full Text PDFWe studied the mechanism for the increase in glucose transport activity that occurs in adipose cells of exercise-trained rats. Glucose transport activity, glucose metabolism, and the subcellular distribution of glucose transporters were measured in adipose cells from rats raised in wheel cages for 6 wk (mean total exercise 350 km/rat), age-matched sedentary controls, and young sedentary controls matched for adipose cell size. Basal rates of glucose transport and metabolism were greater in cells from exercise-trained rats compared with young controls, and insulin-stimulated rates were greater in the exercise-trained rats compared with both age-matched and young controls.
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