Sodium homeostasis is crucial for the control of extracellular volume and blood pressure. Regulation of sodium reabsorption is mainly achieved in the distal nephron by the mineralocorticoid aldosterone, but the molecular pathway of aldosterone action has largely remained unclear.Molecule genetic analysis of inherited diseases distribution sodium homeostasis has now demonstrated that the amiloride-sensitive epithelial sodium channel is a major effector of aldosterone action. Mechanisms by which aldosterone regulates the epithelial sodium channel activity are beginning to emerge and will be of great importance for a better understanding of salt-sensitive hypertension.