Summary
The intravenous injection of a large amount of homologous fibrinogen in the rabbit
produces typical changes in the level of circulating fibrinogen. The first peak is
due to the administered fibrinogen while the second, occurring after 16 hr, is interpreted
as being due to the stimulation of hepatic synthesis and release of preformed fibrinogen.
This typical profile was obtained with different fibrinogen preparations but not with
heterologous fibrinogen. Neither was it obtained after administration of homologous
γ-globulin, α-globulin or albumin. Assuming that enhancement of hepatic synthesis
might be due to fibrinogenolytic products, the effect of the injection of fibrinogen
digest products (FDP) was investigated. Administration of homologous FDP causes, within
24 hours, a significant increase of the plasma fibrinogen level. The critical requirement
of injecting either the protein solution or saline intravenously rather than subcutaneously
is emphasized. In conclusion, FDP appear to be endowed with the novel property of
stimulating fibrinogen synthesis and possibly of causing the release of preformed
fibrinogen.
