Fig. 3

Time course for isoproterenol/adenosine deaminase inhibition of insulin-stimulated GLUT4 translocation and glucose transport

Adipocytes were stimulated with 5 nM insulin for 20 min, at which point 1 µM isoproterenol and 0.5 U/ml adenosine deaminase were added. Cells were then sampled at the indicated time points. Subcellular fractionation, immunoblotting, the amount of GLUT4, and glucose transport were determined as in the legend to Fig. 2. Results of GLUT4 quantitation mean ± SEM (n = 3 separate experiments) and for glucose uptake (mean ± SEM, n = 3 separate experiments) are expressed as percent of maximally insulin-stimulated controls (5 nM insulin for 20 min) (error bar is shown only where this value is greater than the graph symbol). ●, Plasma membranes; ◯, caveolae; ▼, 2-deoxy-D-[1-³H]glucose uptake; ▲, 2-deoxy-D-[1-³H]glucose uptake in control cells without isoproterenol or adenosine deaminase.