[Biological methods of determining free kinins in peripheral blood]

The method is infusing an isolated jejunal strip with heparinized blood (3-5 units/ml) was used to determine total free kinins in peripheral blood of man and animals to a high precision (+/- 6.9%). Kinin formation was inhibited by trypsin inhibitor obtained from soybean (100-200 microgram/ml). Destruction of kinin was blocked by 8-hydroxyquinoline (0.03-0.05 ml of saturated solution per 1 ml of blood) or by unithiol (2,3-dimercaptopropanol-2 mg/ml). Since these inhibitors can induce hypesthesia of the jejunum to bradykinin (8-hydroxyquinoline in 47% of cats) or to potentiate contractility of the jejunal strip (unithiol in 50% of cats) it is advisable that appropriate corrections is made in order to restrict the number of tests, to raise the interval between the tests and to carry out additional analysis of jejunal sensitivity to bradykinin in the presence of 8-hydroxyquinoline or unithiol.