The heparin-dependent inhibition of the accumulation of 131I-fibrinogen in the solid form of Walker-256-carcinosarcoma of the rat

The intravenous injection of 131I-fibrinogen results in a selective accumulation of radioactivity in the solid Walker-256-carcinosarcoma of the rat. An effective anticoagulation with heparin beginning before administration of the radio-iodinated fibrinogen and continued up to the end of the experiment inhibits the enrichment of radioactivity. It is supposed that the radioactivity in the tumor is correlated to the deposition of 131I-fibrin. A clotting process in tumor transforms both fibrinogen and 131I-fibrinogen to fibrin resp. 131I-fibrin. This conversion is thrombin-dependent and might be blocked by heparin. The tumor growth is not influenced by the presence of heparin. (author)