Activation of Plasma Prorenin by Plasminogen Activators in Vitro and Increase in Plasma Renin After Stimulation of Fibrinolytic Activity in Vivo

Plasminogen can be activated by intrinsic activators that circulate in plasma in a precursor form, by extrinsic activator originating from tissues or the vessel wall and by the exogenous activators, urokinase and streptokinase. Tissue activator and vascular activator are probably identical. Dialysis of plasma against pH 4.0 buffer causes denaturation of the plasmin inhibitors, α2-antiplasmin and C1-inhibitor, while α2-macroglobulin is left intact. Incubation of pH 4.0-pretreated plasma with urokinase or streptokinase at pH 7.5 led to activation of plasminogen and prorenin. Incubation of a plasma fraction, which contained plasminogen and prorenin but no α2-antiplasmin and renin, with highly purified tissue plasminogen activator also led to activation of prorenin. The vasopressin analogue, 1-des-amino-8-D-arginine vasopressin (DDAVP), is a potent stimulant for the release of extrinsic activator into the bloodstream. After infusion of DDAVP, 0.4 μg/kg, into normal subjects, parallel increments in plasma fibr...