Summary
A powerful procoagulant is excreted with the human urine. The purification, assay
with purified prothrombin, definition of unit, properties and animal studies are described.
The material is relatively heat resistent, and it activates prothrombin in presence
of Ac-globulin and platelet factor 3 or platelet substitute (brain lipid). Fresh male
human urine contains 10 u/ml. One to 4 u/ml are required to normalize clotting of
hemophilic plasma. Purified preparations exhibit a specific activity around 11,000
u/mg tyrosine. Intravenous injections or infusions of the procoagulant into dogs or
rabbits induce for a few hours a phase of transitory hypercoagulability as indicated
by shortening of recalcification time and enhancement of prothrombin consumption.
This is followed in the rabbit by the appearance of a circulating “antithromboplastin”.