Blood kinins, their concentration in normal subjects and in patients with congenital deficiency in plasma prekallikrein and kininogen.
Kinins are potent vasodilator peptides that may participate in the regulation of local blood flow and blood pressure. Here we report a new method to measure kinins in blood. For this, 6 ml of blood are collected in less than 10 sec directly into 25 ml of ethanol. Kinins are further purified by extracting lipids with ether and by removing kininogen and other interfering substances by chromatography on QAE Sephadex and BioRex 70; then they are measured by a sensitive RIA. In 22 normal subjects, after correction for recovery (50%), the kinin concentration in peripheral venous blood was 25.2 +/- 2.6 pg/ml (mean +/- S.E.M.). To determine whether the circulating kinins are formed by plasma kallikrein or other kininogenases, the concentration of blood kinins was measured in the venous blood of three patients with congenital deficiency in plasma prekallikrein (Fletcher trait) and in one patient with congenital deficiency in the substrate of plasma kallikrein, high-molecular-weight kininogen (Fitzgerald trait). In the three subjects with Fletcher trait, blood kinins were 16, 21, and 31 pg/ml, whereas in the subject with Fitzgerald trait they were 26 pg/ml. Normal subjects had concentrations in the same range (9 to 55 pg/ml), indicating that the concentration of blood kinins in normal subjects is much lower than previously reported (70 to 5000 pg/ml). These results also suggest that kininogenases other than plasma kallikrein may generate circulating kinins.
D000818:Animals; D001778:Blood Coagulation Disorders / Q000097:blood* / Q000151:congenital; D001920:Bradykinin / Q000494:pharmacology; D003429:Cross Reactions; D007610:Kallikreins / Q000032:analysis* / Q000378:metabolism; D007704:Kininogens / Q000097:blood; D007705:Kinins / Q000096:biosynthesis / Q000097:blood* / Q000302:isolation & purification; D011288:Prekallikrein / Q000032:analysis*; D011817:Rabbits; D011863:Radioimmunoassay
D007704:Kininogens; D007705:Kinins; D011288:Prekallikrein; D007610:Kallikreins; D001920:Bradykinin