[The antiheparin thrombocyte factor 4 and its interaction with heparin].

A rat platelet factor has a high antiheparin activity. It also decreases nonenzymatic fibrinolytic activity of normal rat plasma and antithrombin III-heparin complex. The platelet factor 4 formed inactive complexes with heparin in molar ratios of 1:1 and 2:1. Intravenous injection of the platelet factor 4 before injection of albino rats with tissue thromboplastin prevented the reaction of anticoagulation system inactivated the synthesis of endogenous thrombin. This effect is accompanied by high hypercoagulation and depression of nonenzymatic fibrinolysis in blood.