Metabolic adjustments of the kidney involved in the adaptation to potassium loading.

Potassium adaptation involves the development of the ability of the kidneys to secrete large amounts of potassium into the urine. This is accompanied by an adaptive increase in the specific activity of sodium-potassium-ATPase in the kidney, predominantly in the medulla and the papilla, but also involving the cortex. It is likely that these changes are localized to the distal tubule and are especially marked in the collecting ducts although there is no direct evidence bearing on this. Net secretion of potassium in isolated kidneys taken from chronically potassium loaded animals is completely eliminated when ouabain, a specific inhibitor of sodium-potassium-ATPase, is added to the perfusion medium. The secretion of potassium appears also to depend critically on the availability of glucose as substrate.