How does the hormone aldosterone regulate sodium and water balance?

Aldosterone is a steroid hormone secreted by the adrenal glands that serves as the primary regulator of the body's salt and water balance.1

Its regulation of sodium and water occurs through the following mechanisms:

• Renal Action: Aldosterone acts on the kidneys by binding to receptors in the cytoplasm of renal tubular cells. This process "primes" the sodium reabsorption pump, facilitating the reabsorption of sodium ions at the distal tubules back into the blood.12
• Electrolyte Exchange: By increasing sodium reabsorption, aldosterone simultaneously promotes the excretion of potassium and hydrogen ions into the urine.12
• Water Retention: Because water follows sodium through osmotic processes, the increased reabsorption of sodium leads to the retention of water, which helps maintain blood pressure and extracellular fluid volume.12
• Systemic Control: Its production is governed by the renin-angiotensin system, which triggers aldosterone release in response to variations in blood pressure, blood volume, and plasma sodium levels.12