What is the mechanism of action for angiotensin-converting enzyme (ACE) inhibitors?

The mechanism of action for angiotensin-converting enzyme (ACE) inhibitors primarily involves the inhibition of the conversion of angiotensin I to angiotensin II. Angiotensin II is a potent vasoconstrictor and also stimulates the release of aldosterone from the adrenal glands, which promotes sodium and water retention, leading to increased blood volume and pressure.

When ACE inhibitors block the formation of angiotensin II, they effectively reduce its vasoconstrictive effects and lower blood pressure. This ultimately leads to a decrease in aldosterone secretion, reducing fluid retention and helping to lower the workload on the heart in patients with hypertension or heart failure.

By addressing the levels of aldosterone, ACE inhibitors contribute to the overall cardiovascular health by lowering blood pressure and reducing strain on the heart, making Option A the correct representation of their mechanism of action.