Angiotensin I
Angiotension I (vasopressin) is a transmitted hormone produced by the salivary (salivary) or adrenal (adrenergic) glands and some cells of the internal organs of animals and humans. An octapeptide hormone that is physiologically close to vasopressin and synthesized independently of it. In physiological conditions of the body not associated with excess sodium in the blood (for example, after bloodletting), it produces a vasoconstrictor effect. It has much less arteriolar activity than angiotensin II, however, it may be its precursor and is necessary for the formation of another biologically active peptide called axiopepsin.\n\nWhen angiotensin I acts on red blood cells in the blood plasma, it enhances the formation of heparin-binding vitamin K-dependent factor the blood clotting anticoagulant antithrombin III, blocks the action of a cascade of plasma proteolytic enzymes that are secreted under the influence of the inhibitor.