Abstract
Tritiated heparin prepared from porcine intestinal mucosa was fractionated by gel chromatography using Sephadex G-200. The radioactivity of fractions was widely distributed. The obtained fractions were processed for metachromasia of Azur A and anticoagulant activity. These fractions were devided into three main groups designated as high, middle and low molecular heparins. Mean molecular weight, sulfate content, heparin activity and complex formation with plasma protein were investigated on these three groups. These three groups were intravenously injected into rats respectively and their anticoagulant activity, radioactivity in the blood, urinary excretion and tissue distribution were studied in comparison with the whole heparin.
The high molecular heparin had high anticoagulant activity, high sulfate content and great metachromasia, complex with antithrombin III, and was neutralized combining with protamine sulfate. On the other hand, the low molecular heparin had no anticoagulant activity and did not combine with plasma protein or protamine sulfate. When high molecular heparin was administrated into rats, it provided the higher and longer lasting anticoagulant activity and radioactivity in the blood than the whole heparin. 43.8% of radioactivity of injected high molecular heparin was excreted into the urine in three hours and much more of the low molecular heparin was excreted in the same condition, while more radioactivity of injected high molecular heparin accumulated in organs, especially in the liver and kidneys.
Through these experimental results, it is concluded that high molecular heparin would be the most potent and effective form for anticoagulant therapy.
