Aldosterone is released by the adrenal cortex upon stimulation by which molecule?

Aldosterone is released by the adrenal cortex upon stimulation by which molecule?

• A. Renin
• B. Angiotensinogen
• C. Angiotensin I
• D. Angiotensin II

Answer: (D)

Angiotensin II is the molecule that directly stimulates aldosterone release from the adrenal cortex. In the renin-angiotensin-aldosterone system, low blood pressure or low sodium triggers the kidney to release renin. Renin converts angiotensinogen (from the liver) into angiotensin I, which is then converted by ACE into angiotensin II. Angiotensin II acts on the adrenal cortex (zona glomerulosa) to secrete aldosterone, which increases sodium reabsorption and potassium excretion in the distal nephron, helping to raise blood volume and pressure. The other molecules are upstream components or intermediates, not the direct stimulant of aldosterone.

Angiotensin II is the molecule that directly stimulates aldosterone release from the adrenal cortex. In the renin-angiotensin-aldosterone system, low blood pressure or low sodium triggers the kidney to release renin. Renin converts angiotensinogen (from the liver) into angiotensin I, which is then converted by ACE into angiotensin II. Angiotensin II acts on the adrenal cortex (zona glomerulosa) to secrete aldosterone, which increases sodium reabsorption and potassium excretion in the distal nephron, helping to raise blood volume and pressure. The other molecules are upstream components or intermediates, not the direct stimulant of aldosterone.