The Antiheparin Effect of Platelets

Abstract

The antiheparin effect of human platelets has been studied with the following results:

1) Intact platelets counteract heparin. This effect is markedly increased by disintegration of the platelets.

2) Platelet factor 4 is liberated from platelets on storage, especially at higher temperatures.

3) Thrombin enhances the liberation of platelet factor 4.

4) Minute amounts of heparin are adsorbed on the platelets.

5) On a molecular basis, the anticoagulant effect of a heparin-like substance, dextran sulphate, is neutralized to a similar extent as is the anticoagulant effect of heparin.