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.