STUDIES ON ENHANCED FIBRINOLYTIC ACTIVITY IN MAN*

Abstract

Enhanced fibrinolytic activity has been demonstrated to occur in the blood of almost all patients subjected to electroshock and pyrogen injections and in male subjects following severe exercise. A less consistent response has been shown to occur following epinephrine, acetylcholine and ischemia. The plasma euglobulin clot lysis time appears to be a simple and sensitive technique for assaying plasma fibrinolytic activity. The mechanism underlying the appearance of enhanced fibrinolytic activity under the circumstances described has been demonstrated to involve the appearance in the blood of a plasminogen activator. Detailed biochemical studies on plasma of these patients failed to reveal evidence of increased amounts of plasmin or decreased plasminogen or anti-plasmin levels. It is suggested on the basis of the evidence presented that the enhanced fibrinolytic activity was produced by the direct activation of intrinsic clot plasminogen rather than increased amounts of circulating plasmin.