The Antiheparin Effect of α1-Acid Glycoprotein and Platelet Material, Evaluated by the Heparin Thrombin Clotting Time

Abstract

The effect on the heparin thrombin clotting time (HTCT) of a so-called acute phase protein, α₁-acid glycoprotein, was studied in test systems consisting of purified fibrinogen, antithrombin III, heparin and thrombin, and compared to the effect of platelet material (crude platelet factor 4). In these test systems a physiological concentration of α₁-acid glycoprotein (1 g/l) inhibited heparin more effectively than did soluble platelet material from 200 × 10⁹ platelets/1. The present observations suggest that α₁-acid glycoprotein is of great significance for the so-called heparin tolerance, whereas platelet material proved less important.