The effect of guanidino substances from uremic plasma on insulin binding to erythrocyte receptors in uremia.

We have studied insulin binding to erythrocyte receptors in a group of 25 nonobese, nondiabetic uremic patients undergoing maintenance hemodialysis for 2-54 months and 14 healthy controls. Erythrocytes of predialyzed uremics bind significantly less insulin than control erythrocytes (p less than 0.01). Dialysis resulted in a rapid increase of insulin binding (p less than 0.001). The concentrations of plasma insulin and glucose remained essentially unchanged during 5-hour hemodialysis and did not significantly differ from the control values. The down regulation of insulin receptors in undialyzed patients in the presence of normal plasma insulin concentration indicates that factors other than insulin itself could be responsible for insulin receptor activity during uremia. The results demonstrated that creatinine, creatine and glycocyamine have a direct suppressive effect on insulin binding of postdialyzed plasma (p less than 0.05) in concentration of 1 mmol/l. This suggested that specific uremic toxins could play an important role in the mechanisms of altered insulin binding during hemodialysis. Despite the high concentration of these compounds in blood of uremics, the only common feature for these compounds is the presence of the guanidino group in the molecule.