What is the effect of angiotensin-converting enzyme (ACE) inhibitors?

Angiotensin-converting enzyme (ACE) inhibitors are primarily designed to lower blood pressure by decreasing vascular resistance. They achieve this by inhibiting the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. By blocking this conversion, ACE inhibitors cause relaxation of blood vessels, which leads to a decrease in overall vascular resistance and, consequently, a reduction in blood pressure.

Additionally, the reduction of angiotensin II also decreases the secretion of aldosterone, which in turn reduces sodium reabsorption in the kidneys. This promotes natriuresis (the excretion of sodium in urine), further contributing to lower blood volume and aiding in blood pressure reduction.

It’s important to note that the other effects listed in the choices do not reflect the primary action of ACE inhibitors. For instance, they do not promote sodium reabsorption, as their overall action tends to facilitate sodium loss via the kidneys. Similarly, they do not increase blood pressure or enhance heart contractility; rather, they are used to manage conditions marked by high blood pressure and heart strain, such as hypertension and heart failure.