Insulin release at physiologic potassium concentrations.

While high concentrations of potassium directly stimulate pancreatic insulin release, it has not been shown whether potassium ions within the physiologic range produce the same effect. Rats fed a low potassium diet were given KCl intraperitoneally. Insulin levels measured in the portal vein were significantly elevated (172.9 +/- 17 vs 76.5 +/- 14.9 microunits/ml, p less than .05) at 30 minutes, compared to peripheral insulin levels in which the increase did not reach significance. Thus insulin, when measured in portal vein blood samples, is significantly released by potassium increments within the normal range in the absence of exogenous glucose loads.