Angiotensin is synthesized in the liver as angiotensinogen. When blood pressure drops, the kidneys release an enzyme called renin, which converts angiotensinogen into angiotensin I. Angiotensin I is then converted into angiotensin II by the angiotensin-converting enzyme (ACE) primarily in the lungs. Angiotensin II acts on various organs to increase blood pressure by causing vasoconstriction, stimulating aldosterone secretion from the adrenal glands, and promoting sodium and water retention by the kidneys.
