Abstract
Summary
A highly purified bovine aortic proteoglycan (PG) prolongs thrombin-in-duced clotting and inhibits thrombin-in-duced platelet aggregation, but has no appreciable effect on platelet aggregation induced by ADP, epinephrine, or collagen. Inhibition of thrombin-induced aggregation requires the presence of plasma factors. Glycosaminoglycans (GAG) isolated from the PG contained all the antithrombic activity. Hydrolysis of GAG by treating the PG with chondroitinase abolishes the activity. The antithrombic action of the PG was compared with that of a commercial heparin. Twice as much protamine sulfate was required to neutralize the antithrombic effect of the PG as to neutralize that of heparin. The location of the PG in the arterial wall and its antithrombic activity suggest it plays a role in regulating the response of the circulating blood to vascular injury.
We thank Miss Cassandra Smith and Miss Rose Lo for excellent technical assistance. Miss Ellen Rohde typed the manuscript.
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