Inhibitory Effects of Estrogens on Antithrombin III.

After the addition of purified estrogen preparation to the plasma, the anticoagulant activity of antithrombin III measured by Bigg’s method decreases in proportion to the amount of estrogen added. And the biological activity of antithrombin III in the plasma mixed with estrogen decreases proportionally in single immunodiffusion assay with anti-antithrombin III serum. The same findings mentioned above are also observed in the experiences with estron, equilin, equilenin and estradiol.

Furthermore, the rocket formation of antithrombin III fraction prepared by Abild-gaard’s method in crossimmunoelectrophresis also disappeares by the addition of estrogen into the reaction mixture, and the electric mobility of antithrombin III fraction with estrogen increases the migration to the anode in polyacrylamide gel electrophoresis.