INTRINSIC PLASMA FIBRINOLYSIS - INVOLVEMENT OF UROKINASE-RELATED ACTIVITY IN THE FACTOR-XII INDEPENDENT PLASMINOGEN PROACTIVATOR PATHWAY

  • 1 January 1984
    • journal article
    • research article
    • Vol. 103  (3) , 408-419
Abstract
A portion of human blood fibrinolytic activity can be quenched by antibodies to urokinase. This portion and its position in the 3 pathways (extrinsic, intrinsic factor XII dependent, and intrinsic factor XII independent) of plasminogen activator activity that were defined in the DEF [dextran sulfate euglobulin] of plasma. Activity quenching in various plasmas (including plasma adsorbed by agarose-bound AUK [antiurokinase]) demonstrated the involvement of a discrete activator activity of 40-50 BAU[blood activator unit]/ml with little variation among individuals (43 .+-. 6 (SD) BAU/ml, n = 13). The quenching did not involve, quantitatively or qualitatively, the extrinsic (tissue-type) plasminogen activator activity varying between 1 and 146 BAU/ml in baseline plasma and in plasma obtained after stimulation by venous occlusion, exercise, or DDAVP [1-desamino-8-D-arginine vasopressin] administration. In confirmation, extrinsic activator activity was recovered in plasma adsorbed by agarose-bound AUK. The quenching also did not involve the factor XII-dependent activities; it was quantitatively normal in plasma with Hageman (n = 3) and Fletcher (n = 2) traits, and AUK did not interfere with the generation of factor XII-dependent fibrinolytic activity by addition of purified activated factor XII in plasma with Hageman trait. There was no effect of AUK on kallikrein generation, kallikrein activities, or the APTT [activated partial thromboplastin time], nor were these aspects altered in depleted plasma. The quenching involved the factor XII-independent system of intrinsic fibrinolysis. Addition of purified urinary urokinase did not result in restoration of missing activity in plasma adsorbed by AUK-agarose. The quenching probably involved an apparent urokinase-related activator component in plasma.