How do the kidneys control sodium and potassium levels in the blood?

The kidneys maintain sodium and potassium balance primarily through processes occurring in the distal convoluted tubule and the collecting duct, where they regulate the reabsorption of sodium and the secretion of potassium.123

The Role of Aldosterone

The hormone aldosterone, secreted by the adrenal gland, is the primary regulator of this process. When the body is sodium-deficient or blood pressure drops, aldosterone is released to facilitate the reabsorption of sodium ions back into the blood. This mechanism is linked to an exchange process: as sodium is reabsorbed, potassium and hydrogen ions are secreted into the tubule to be eliminated in the urine.14523

Feedback Mechanisms

This system is tightly controlled by the renin-angiotensin system. The kidneys release the enzyme renin in response to variations in blood pressure and plasma electrolyte levels. Renin triggers a cascade that results in the production of angiotensin II, which stimulates the adrenal glands to release aldosterone, thereby adjusting electrolyte levels to maintain homeostasis.45