Question

Aldosterone synthesis is stimulated by which of the following ?

• A. ACTH
• B. Hyperkalemia
• C. Hypernatremia
• D. Exogenous steroids

Answer 1

The Correct Option is B

Step 1: Rank the regulators. The zona glomerulosa responds to several signals, but their potency runs hyperkalemia > angiotensin II > ACTH > hyponatremia.

Step 2: Justify the top stimulus. A rise in plasma potassium is the dominant trigger because aldosterone then drives renal potassium loss, closing a tight feedback loop that keeps body potassium balanced.

Step 3: Dismiss the rest. ACTH contributes only a small diurnal rhythm, not steady control. High sodium suppresses aldosterone, so hypernatremia is wrong, and only low sodium weakly stimulates it. External steroids play no stimulatory role.

The most powerful physiological driver is the potassium signal.\[\boxed{\text{Hyperkalemia}}\]