The Molecular Basis of Renal Potassium Excretion

Potassium is the most abundant cation in the body and most is stored inside the cells. The Na,K-ATPase maintains the high intracellular potassium concentration that defines the electrophysiological properties of the cell membrane. This is essential for the physiological function of excitable cells, such as nerve and muscle, and nonexcitable cells, such as those in epithelia. Changes in intracellular potassium contribute to cell volume regulation, secretion of hormones, and the maintenance of acid–base balance. Systemic potassium homeostasis occurs through a coordinated process linking dietary intake with excretion. The kidney under the control of the renin-angiotensin-aldosterone system achieves long-term potassium balance.