Angiotensin I

Definition

Angiotensin I is an inactive precursor peptide that is converted into angiotensin II by the enzyme angiotensin-converting enzyme (ACE). It plays a crucial role in the Renin-Angiotensin-Aldosterone System (RAAS), which regulates blood pressure and fluid balance.

5 Must Know Facts For Your Next Test

1. Angiotensin I is produced from angiotensinogen, which is released by the liver.
2. The conversion of angiotensin I to angiotensin II occurs primarily in the lungs through the action of ACE.
3. Angiotensin II, formed from angiotensin I, is a potent vasoconstrictor that increases blood pressure.
4. ACE inhibitors are a class of antihypertensive drugs that prevent the conversion of angiotensin I to angiotensin II.
5. Measurement of plasma levels of angiotensin I can be used to assess renin activity in patients with hypertension.

Review Questions

• What role does angiotensin I play in blood pressure regulation?
• How is angiotensin I converted into its active form?
• Why are ACE inhibitors important in managing hypertension?

Related terms

Angiotensin II: A potent vasoconstrictor derived from angiotensin I that significantly raises blood pressure.

ACE Inhibitors: A group of medications that inhibit the conversion of angiotensin I to angiotensin II, thereby lowering blood pressure.

Renin: An enzyme secreted by the kidneys that catalyzes the formation of angiotensin I from angiotensinogen.