ANGIOTONIN-ACTIVATOR, RENIN- AND ANGIOTONIN-INHIBITOR, AND THE MECHANISM OF ANGIOTONIN TACHYPHYLAXIS IN NORMAL, HYPERTENSIVE, AND NEPHRECTOMIZED ANIMALS

摘要: 1. Angiotonin does not exert its vasoconstrictor effect in the absence of a substance contained red blood cells and serum which we have called "angiotonin-activator." A fraction has been separated from angiotonin-activator is concentrated. It contains little or no reninactivator. 2. Repeated intravenous injections angiotonin into animals causes pressor response gradually to lessen finally disappear (the phenomenon tachyphylaxis), but much more slowly than when renin injected. When abolished, also fails act. Large doses reduce abolish responsiveness angiotonin. Exhaustion renin-activator abolishes without abolishing 3. Blood made tachyphylactic by infusion greatly reduced amounts angiotonin-activator. An inhibitor appears blood. 4. Bilateral nephrectomy prolongs enhances rise arterial pressure following injection renin. The enhancement reaches maximum 24 30 hours after operation. these exhibits increased ability activate tested isolated perfused organs. are required amount activator their Renin-activator simultaneously affected. 5. Tranfusion an animal nephrectomized dog reduces latter added recipient transfusion through rabbit's ear action. 6. Transfusion normal large hypertensive dogs recipient's If renintachyphylaxis established donor, recipient. such properties organ with 7. Renin-tachyphylactic normals dog's elevated single dogs. 8. Nephrectomized exhibit greatest renin, least, about midway between.