Plasma Levels of Various Blood Clotting Factors in Germfree Rats. ∗

Summary

A group of 7 germfree rats had a somewhat lower mean plasma level of antihemophilic A factor (factor VIII) than 7 control rats. The difference was not statistically significant. There were no differences between the 2 groups of animals in their mean plasma levels of fibrinogen (factor I) and proaccelerin (factor V), which are the 2 other blood clotting factors possibly produced in the reticuloendothelial system. All rats received the same daily dose of vit. K₁ in their food. The germfree rats, however, showed a higher mean plasma level of antihemophilic B factor (factor IX) and Stuart-Prower factor (factor X) than the control rats, the difference in the latter factor being statistically significant at the 5% level. No other differences were detected between the 2 groups of animals as far as known blood clotting factors are concerned.