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How does aldosterone act on the kidneys to conserve sodium and water?
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Steroid
Many important physiological functions of vertebrates are controlled by steroid hormones.
Aldosterone is a steroid hormone that regulates the body's salt and water balance by acting on the kidneys.12
To conserve sodium and water, aldosterone functions through the following mechanism:
- Binding and Activation: The hormone binds to and activates specific receptors located in the cytoplasm of renal tubular cells.12
- Ion Channel Production: Once activated, these receptors stimulate the production of ion channels within the renal tubular cells.12
- Reabsorption and Excretion: These channels facilitate the increased reabsorption of sodium back into the blood, which helps retain water. Simultaneously, the process increases the excretion of potassium into the urine.12
This process is primarily regulated by the renin-angiotensin system, which responds to changes in blood pressure, blood volume, and electrolyte levels.32