Effect of glucose on beta-adrenergic induced downregulation of insulin receptor binding in human fat cells

The effect of beta-adrenergic stimulation on specific insulin binding to isolated human fat cells was investigated at 24°C and at 37°C. In the abscense of glucose isoprenaline caused a 40% decrease in high affinity insulin binding at both temperatures. At 37°C the reduction in binding was completely offset by the addition of glucose to the medium. A maximum effect of glucose occured at 5 mmol/l. At 24°C, however, there was no effect of glucose on insulin binding. The effects of glucose and isoprenaline on insulin binding were not related to the lipolytic activities these two agents. In conclusion, low amounts of glucose prevent catecholamine induced down-regulation of insulin receptor binding in human fat cells at physiological temperature.