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How does aldosterone regulate salt and water balance?
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Endocrine system
The glands of the human endocrine system.
Aldosterone is a steroid hormone secreted by the adrenal glands that serves as the primary regulator of the body's salt and water balance. It functions as a mineralocorticoid, primarily acting on the kidneys to maintain electrolyte homeostasis.12
The hormone regulates these levels through the following mechanisms:
- Sodium Retention: Aldosterone binds to receptors in the cytoplasm of renal tubular cells. This action stimulates the production of ion channels, which facilitates the reabsorption of sodium ions from the distal tubules back into the blood.23
- Water Balance: By increasing the reabsorption of sodium, aldosterone indirectly promotes the retention of water, which is essential for maintaining proper blood volume and blood pressure.12
- Potassium Excretion: As it promotes sodium reabsorption, aldosterone simultaneously increases the excretion of potassium and hydrogen ions into the urine.23
The production of aldosterone is controlled by the renin-angiotensin system, which responds to variations in blood pressure and plasma electrolyte levels.23