Circulating Fibrinogen Degradation Products (FDP) in Dog Blood after Intravenous Thrombin Infusion

Abstract

Summary1. The effect of thrombin infusion into dogs was studied with the use of 131I-labelled fibrinogen and compared with the better known effect of plasmin.2. Rapid infusion of thrombin brings about almost complete defibrination followed by the appearance of high molecular fragments of the fibrinogen molecule.3. Some anticoagulant activity of plasma, but not as pronounced as after plasmin infusion, is observed in the case of thrombin infusion.4. A hypothesis is discussed, according to which the proteolytic degradation of fibrin which is formed as a result of thrombin action, and cleared out of the circulating blood, does occur. The products are then released back into the circulation system.