Summary
1. In vivo studies in rabbits have shown that the liver diminishes the thrombo-genicity of infused
human serum.
2. In vitro rabbit liver perfusions with human serum have demonstrated the loss of serum thrombogenicity
within 5 min after the onset of the perfusion. Associated with this loss of thrombotic
capacity is a marked decrease in the activation product (AP) and labile factor IX
(PPA) activity in the infused serum.
3. The liver appears to have the capacity to discriminate between circulating activated
clotting activities such as AP and PPA and inactive procoagulants such as stable or
genuine factor IX, factor VII and factor X. The latter are not cleared from the circulation
by the liver.
4. These studies provide some insight into the mechanism whereby circulating activated
clotting activities and retarded blood flow predispose to thrombosis.
