The Reduction of Autoprothrombin II Activity with Dicumarol

Abstract

It is generally considered that the administration of dicumarol is followed by a decrease in prothrombin concentration, and it has been suggested that another plasma factor may also decrease. We have found that there are two derivatives of prothrombin called autoprothrombin and autoprothrombin II. In this paper we present data which show that the concentration of autoprothrombin II can be reduced practically to zero with the use of Dicumarol without observing a bleeding tendency. The decrease in concentration coincides with a decrease in prothrombin concentration but is relatively more rapid.