- A family of peptides (smaller than proteins) that act as vasoconstrictors to narrow blood vessels.
* * *A family of peptides of known and similar sequence, with vasoconstrictive activity, produced by enzymatic action of renin upon angiotensinogen. See a. I, a. II, a. III.
* * *1) either of two forms of a kinin of which one has marked physiological activity and the other is its physiologically inactive precursor esp ANGIOTENSIN II2) a synthetic amide derivative of angiotensin II used to treat some forms of hypotension
* * *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 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.
* * *an·gio·ten·sin (an″je-o-tenґsin) any of a family of polypeptide vasopressor hormones formed by the catalytic action of renin on angiotensinogen. Called also angiotonin.
Medical dictionary. 2011.