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How does the renin-angiotensin system control aldosterone secretion?
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Hormone
Many important physiological functions of vertebrates are controlled by steroid hormones.
The renin-angiotensin system regulates aldosterone secretion through a feedback mechanism triggered primarily by changes in blood flow and pressure in the kidneys.123
The process functions as follows:
- Renin Release: When blood flow to the kidneys decreasesâoften due to low blood pressure, sodium loss, or dehydrationâspecialized cells in the juxtaglomerular apparatus secrete the enzyme renin into the blood.123
- Angiotensin Formation: Renin converts the plasma protein angiotensinogen into angiotensin I. An enzyme called angiotensin-converting enzyme (ACE) then converts angiotensin I into angiotensin II.142
- Aldosterone Secretion: Angiotensin II travels to the adrenal glands, where it binds to specific receptors to stimulate the secretion of aldosterone.12
Once released, aldosterone acts on the kidneys to increase the reabsorption of sodium and water, which helps restore blood volume and pressure. While this system is the primary regulator, aldosterone secretion can also be stimulated by high serum potassium levels or, to a lesser extent, by corticotropin.432