Biochemistry · Molecule
Aldosterone !
The zona glomerulosa mineralocorticoid: it makes the kidney keep sodium and water and excrete potassium and hydrogen ions.
Updated 2026-11-01
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Key facts
- Angiotensin II and high potassium stimulate it; ACTH plays a minor role.
- It acts on the mineralocorticoid receptor of collecting duct principal cells: more ENaC channels and more Na⁺/K⁺ pump.
- Result: sodium and water retention, potassium and hydrogen ion loss (metabolic alkalosis).
- Its precursor 11-deoxycorticosterone also has mineralocorticoid action: that is why some adrenal hyperplasias come with hypertension.
- Formula
- C21H28O5
- PubChem
- CID 5839
Structure
- A 21-carbon steroid with an aldehyde on carbon 18 (hence its name), which forms a hemiacetal with the 11β-hydroxyl.
- Its last step is done by aldosterone synthase (CYP11B2): 11β-hydroxylation, 18-hydroxylation and 18-oxidation.
Clinical notes
- Primary hyperaldosteronism (Conn syndrome): hypertension, low potassium and suppressed renin.
- Spironolactone and eplerenone block its receptor (resistant hypertension, heart failure, cirrhosis with ascites).
- Its lack in salt-wasting adrenal hyperplasia causes low sodium, high potassium and dehydration in the newborn.
Related conditions
- Arterial hypertension
- Adrenal insufficiency
- Congenital adrenal hyperplasia due to 21-hydroxylase deficiency
- Heart failure
Related
- Adrenal enzymes and congenital adrenal hyperplasia
- 21-Hydroxylase (CYP21A2)
- 11β-Hydroxylase (CYP11B1)
- Cortisol
- Na⁺/K⁺-ATPase (sodium pump)
- Nuclear receptors
- Angiotensin-converting enzyme (ACE)
Test yourself
Think of the answer, then tap the question to see it.
Which two main stimuli raise aldosterone?
Angiotensin II and hyperkalaemia.
Which cells does aldosterone act on, and which proteins does it increase?
Collecting duct principal cells; it increases ENaC sodium channels and the Na⁺/K⁺-ATPase.
Which lab changes does primary hyperaldosteronism cause?
Hypokalaemia, metabolic alkalosis and suppressed renin with high aldosterone.
Molecules are shown in their neutral form, as the databases deposit them; in the cell the acids and phosphates are ionised.
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Aldosterone (CID 5839) (PubChem, NCBI, 2026) · Public domain; NR3C2: Mineralocorticoid receptor (human) (UniProt, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).
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Representative model, for educational purposes only.