Change in affinity of insulin receptors following oral glucose in normal adults.

125I-insulin binding to circulating monocytes has been studied in 4 normal volunteers in the basal state as well as at 2 and 5 hours after ingestion of 100 g of glucose. In each study five hours after glucose ingestion, the competition-inhibition curve was shifted to the left and was steeper than that in the basal study; the amount of insulin that caused a 50% decrease in specific binding of 125I-insulin in the basal study was 3-11 fold higher than at 5 hours after glucose. These changes in binding after glucose ingestion were largely due to major alterations of receptor affinity. We conclude that acute changes in receptor affinity occur normally as part of the physiologic regulation of target cell sensitivity to hormonal stimulation.