Insulin and potassium have a feedback mechanism, so that if, for example, blood levels of potassium get too high, insulin is released from the beta cells to help lower the levels. There is some indication that people who have metabolic syndrome or type 2 diabetes have a low level of potassium in their cells.
Hyperkalemia is a common clinical problem. Potassium enters the body via oral intake or intravenous infusion, is largely stored in the cells, and is then excreted in the urine. The major causes of hyperkalemia are increased potassium release from the cells and, most often, reduced urinary potassium excretion.
Potassium levels can fluctuate severely during the treatment of DKA, because insulin decreases potassium levels in the blood by redistributing it into cells via increased sodium-potassium pump activity. A large part of the shifted extracellular potassium would have been lost in urine because of osmotic diuresis.