[Activation of the anticoagulation system following intravenous administration of beta-thrombin]

Beta-thrombin possessing high esterase activity and tracing coagulating ability, being product of limited proteolysis of alpha-thrombin in vitro, accelerates recalcification time and thrombin generation in plasma, but not the conversion of prothrombin to enzyme. Thus, beta-thrombin is the activator of early stages of blood coagulation, does not possess fibrinolytic activity and does not activate plasminogen. The i. v. administration of beta-thrombin to rats induces changes in blood coagulability which are accompanied by an increase in plasma recalcification time, total fibrinolytic activity and non-enzymatic fibrinolysis. Nothing of the kind occurs after administration alpha-thrombin, having tracing clotting activity similar to R-thrombin activity. The data obtained suggest the possibility of reflex activation of the anticoagulating system by beta-thrombin or undirectly by alpha-thrombin generated by beta-thrombin activation at early stages of blood coagulation.