Sulfonylurea potentiates insulin-induced recruitment of glucose transport carrier in rat adipocytes.
Sulfonylureas potentiate the insulin-induced stimulation of glucose transport in adipocytes. In order to elucidate the molecular mechanism of this potentiation, effects of a long-term (48-h) incubation with glyburide (2 micrograms/ml) on the relative sizes of the plasma membrane, the microsome, and the total membrane pools of the glucose-sensitive cytochalasin B binding were studied for basal and insulin-stimulated adipocytes. The drug treatment potentiated an insulin-induced stimulation of 3-O-methyl-D-glucose flux by 31 to 45%, with little effect on the basal flux. The same drug treatment increased the plasma membrane pool size of the glucose-sensitive cytochalasin B binding in the insulin-stimulated adipocytes with a concomitant decrease in the microsomal pool size. This effect was minimal, if any, in basal adipocytes. The drug treatment did not affect the total glucose-sensitive, cytochalasin B binding capacity of adipocyte membranes. These results indicate that the drug treatment increases the insulin-induced recruitment of the glucose carrier from the microsome to the plasma membrane by 27-31%. It is concluded that potentiation of the insulin-induced stimulation of the hexose transport by sulfonylureas is mainly due to a potentiation of the insulin-induced recruitment of the glucose carrier.
D019325:3-O-Methylglucose; D000273:Adipose Tissue / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D003571:Cytochalasin B / Q000378:metabolism; D004357:Drug Synergism; D005905:Glyburide / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008757:Methylglucosides / Q000378:metabolism; D009004:Monosaccharide Transport Proteins; D051381:Rats; D011919:Rats, Inbred Strains; D013453:Sulfonylurea Compounds / Q000494:pharmacology*; D013997:Time Factors
D002352:Carrier Proteins; D007328:Insulin; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D013453:Sulfonylurea Compounds; D019325:3-O-Methylglucose; D003571:Cytochalasin B; D005905:Glyburide