The Effect of Potassium Chloride Infusion on Insulin Secretion In Vivo

Infusion of KCl (0.25-3.0 mEq/kg/hr) into three intact dogs, four with bilateral ureteral ligation, and six animals with bilateral nephrectomy produced a rise of peripheral plasma insulin levels and a gradual fall of plasma glucose concentrations. The percent fall of glucose levels was correlated (r = 0.83, p < .001) with the duration of the infusion. There was no change in the fasting hyperglycemia and barely detectable plasma insulin levels in three pancreatectomized dogs infused with KCl. Four dogs were sampled from their posterior superior duodenal veins. Three showed a marked rise in insulin levels within five minutes when the potassium concentration was relatively unchanged and the other manifested late elevated central insulin levels when peripheral plasma values had returned to normal. These data suggest that changes in potassium concentration stimulate insulin secretion in vivo and the resultant inhibition of hepatic glucose production causes a progressive decline in systemic glucose concentration. The possibility of an insulin-potassium feedback system is discussed briefly.