n. either of two peptides: angiotensin I or angiotensin II. Angiotensin I is derived, by the action of the enzyme renin, from a protein (alpha globulin) secreted by the liver into the bloodstream. As blood passes through the lungs, another enzyme, angiotensin-converting enzyme (ACE), acts on angiotensin I to form angiotensin II. This peptide causes constriction of blood vessels and stimulates the release of the hormones vasopressin and aldosterone, which increase blood pressure. See also ACE inhibitor, angiotensin II antagonist.
Subjects: Medicine and Health — Chemistry.