Potassium homeostasis in chronic experimental diabetes mellitus in rats

Blunted kaliuresis after an acute oral potassium load in diabetes mellitus

It is unknown whether diabetic patients without renal failure or aldosterone deficiency respond normally to potassium administration. Acute oral potassium-loading was carried out in eight diabetic patients with modestly reduced creatinine clearance (Ccr) and in 11 diabetic patients and 13 controls with normal clearances. Only one diabetic patient manifested an inappropriately low upright plasma aldosterone level (6 ng/dL). The percentage of potassium excreted in 4 hour by both groups of diabetic patients was significantly less than that of the controls (decreased Ccr:21% +/- 6%, normal Ccr:36% +/- 5%, controls:54% +/- 5%; p less than 0.01 and 0.05 respectively). On the other hand, the estimated amount of potassium translocated intracellularly tended to be greater in the diabetic patients (18 +/- 3 mmol; 11 +/- 3 mmol) than controls(7 +/- 2 mmol; p less than 0.005 and 0.1 respectively), and the ratio of the increase in plasma (K) to the amount of potassium retained, was lower in diabetic patients, probably indicating enhanced intracellular potassium translocation. The authors conclude that diabetic patients with normal or only slightly reduced renal function (and no aldosterone deficiency) may have a reduced capacity to excrete an acute potassium load but an enhanced capacity to transfer potassium intracellularly.