Abstract
The distal nephron is the portion of the nephron that extends from the ascending limb of Henle to the collecting duct. This article summarizes some of the physiological functions of the distal nephron, with particular emphasis on the physiological functions of transepithelial transport of sodium, potassium, and chloride. The pathophysiology of the following diseases with dysfunction of the distal nephron is reviewed. (1) Liddle syndrome: a familial disorder with clinical manifestations very similar to primary aldosteronism but with reduced aldosterone secretion. (2) Bartter syndrome/Gitelman syndrome: a group of disorders presenting with renal sodium and potassium wasting. (3) Type II pseudohypoaldosteronism: a group of inherited hypertensive disorders with sodium retention due to the hyperactivity of the newly discovered WNK (with no lysine kinase 4)-NCC (Na+-Cl− cotransporter) signaling cascade. Beginning with the identification of the causative genetic abnormalities, rapid progress has been made in understanding the pathogenesis of these diseases at the molecular and cellular levels, resulting in the identification of new regulatory mechanisms of electrolyte transport in the kidney.
