Evidence for a humoral agent capable of raising vitamin-K-dependent coagulation factors in rabbits.

Abstract

Summary. Evidence is presented for the existence of a humoral factor, obtained from rabbits treated with coumadin, which is capable of raising the vitamin‐K‐dependent coagulation factors II, VII, IX and X when injected into recipient animals. Thirteen rabbits were injected with varying volumes of test donor plasma (obtained from coumadin‐treated rabbits) over varying periods of time. A positive response in coagulation factor level (greater than 2 S.D. on 2 consecutive days) was obtained in 12 out of 13 animals for factor II, six out of eight animals for factor VII, six out of nine animals for factor IX and nine out of 13 animals for factor X. Ten rabbits were injected with control donor plasma from control rabbits injected with physiologic saline instead of coumadin. No risc was obtained in eight out of 10 rabbits for factor II nor in any of the animals examined for factors VII, IX and X (two, eight and seven animals respectively). The non‐vitamin‐K‐dependent coagulation factor V rose non‐specifically in four out of 11 recipient rabbits injected with test donor plasma and three out of nine injected with control donor plasma.