Acute effects of cycloheximide on the translocation of glucose transporters in rat adipose cells.
Insulin's rapid action to increase glucose transport is believed to occur primarily through the translocation of glucose transporters from an intracellular pool to the plasma membrane. To better understand the mechanism involved, we studied the role of protein synthesis in glucose transporter translocation by using the protein synthesis inhibitor, cycloheximide. Isolated rat epididymal adipose cells were incubated in the presence or absence of cycloheximide (10 micrograms/ml) for a total of 120 min. Insulin (7 nM) was added to half of the cells from both groups for the final 30 min. Protein synthesis was inhibited by approximately 90%, as measured by [14C]leucine incorporation, in the cells exposed to cycloheximide. The 3-O-methylglucose uptake in intact cells was slightly increased in the basal state with cycloheximide treatment, but the insulin-stimulated 3-O-methylglucose uptake was unchanged by cycloheximide. The distribution of glucose transporters in the different subcellular membrane fractions, as measured by the cytochalasin B binding assay, was unchanged by cycloheximide. These results suggest that insulin's stimulation of glucose transport and translocation of glucose transporters can occur without acute protein synthesis.
Jones
T L
TL
Experimental Diabetes, Metabolism and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
Cushman
S W
SW
D019325:3-O-Methylglucose; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology*; D003571:Cytochalasin B / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D008297:Male; D008757:Methylglucosides / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D014176:Protein Biosynthesis; D051381:Rats
D007328:Insulin; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D019325:3-O-Methylglucose; D003571:Cytochalasin B; D003513:Cycloheximide; D007930:Leucine