Summary
The heparinoid G31150-A and nitrilotriacetic acid (NTA) were compared with heparinoid G31150 and heparin. In vitro the anticoagulant activity of NTA was 1/20000, G31150-A 1/8th and G31150, 1/10th of heparin. On intravenous injection in dogs, the degree and duration of hypocoagulability was about the same for the two heparinoids but less than predicted from the effects in vitro. Injection of 25 mg NTA/kg caused a slight increase in coagulation time lasting over 4 hours. When heparinoid G31150-A and NTA were given orally, there was an increase in clotting time of blood and metachromatic activity appeared in the urine. The greatest amount of activity was excreted with the highest dose of NTA alone. Microelectrophoresis of the urinary concentrate indicated the excreted material after NTA was not heparin, but another mucopolysaccharide; after G31150, a heparinoid. These results were confirmed by the resulting absorption spectrum of the dye obtained with added urinary concentrate. It is suggested that the effects produced when a chelating agent is given with oral heparin and heparinoids may be due to the release of a mucopolysaccharide.
