Insulin infusion and serum potassium in normal subjects

Two groups of healthy males of normal body mass index underwent hyperinsulinaemic glucose clamp procedures during studies of insulin resistance. Insulin was infused for 2 consecutive 100 minute periods at 40 and 400 mU.m-2.min-1, plasma glucose being maintained by 20% dextrose infusion via a Biostator. One group received 20 mmol/l potassium chloride in the dextrose infusate, calculated to replace the extracellular potassium deficit due to the action of insulin on potassium flux. Despite this, serum potassium fell equally in both groups in response to each level of insulin infusion.