Stimulation of fibrinogen synthesis by thrombin in rabbits with ancrod-induced afibrinogenemia

¹ Division of Hematology, Department of Medicine, The Johns Hopkins University School of Medicine and The Johns Hopkins Hospital, Baltimore, Maryland 21205

The effect of intravenous infusions of thrombin on fibrinogen synthesis was evaluated in rabbits rendered afibrinogenemic by ancrod. Fibrinogen production and catabolism were measured simultaneously with ⁷⁵Se-labeled selenomethionine (⁷⁵SeM) and with ¹²⁵I-labeled fibrinogen injected 5, 12, 18, or 26 h after ancrod. In normal rabbits the infusion of ancrod (2 U/kg body mass during 1 h) did not alter fibrinogen synthesis nor did it affect the rate of fibrinogen catabolism measured during a period of 5–120 h after ancrod administration. Normal rabbits that received purified bovine thrombin (100 U/kg body mass during 1 h) exhibited a twofold stimulation of fibrinogen synthesis as measured by the incorporation of ⁷⁵SeM injected 5 h after thrombin. Rabbits made afibrinogenemic by infusion of ancrod 5 h before thrombin also showed a twofold increase in fibrinogen synthesis, as did animals that received ancrod immediately after thrombin. These experiments show that ancrod alone has no effect on fibrinogen production, and that thrombin stimulates fibrinogen synthesis in afibrinogenemic rabbits to the same extent as in controls.

fibrinogen-fibrin degradation products; fibrinogen catabolism

Submitted on March 29, 1977