ACE inhibitors are responsible for the conversion of what substances?

ACE inhibitors, or Angiotensin-Converting Enzyme inhibitors, play a crucial role in the renin-angiotensin-aldosterone system (RAAS) by inhibiting the conversion of angiotensin I to angiotensin II. Angiotensin I is an inactive precursor that is transformed into angiotensin II, a potent vasoconstrictor that increases blood pressure and stimulates the release of aldosterone, which in turn leads to sodium and water retention.

By blocking this conversion, ACE inhibitors lower the levels of angiotensin II, resulting in vasodilation and reduced blood pressure. This mechanism is particularly beneficial in treating conditions like hypertension and heart failure. The reduction of angiotensin II also has a secondary effect of decreasing aldosterone secretion, which further helps in managing fluid retention. Thus, the choice that correctly identifies the role of ACE inhibitors in this process is the conversion of angiotensin I to angiotensin II.