Fibrinogen synthesis in the rat; role of the C terminal end of the gamma chain of fragment D1.

The terminal fibrinogen degradation product fragment D1 is known to regulate fibrinogen synthesis but the determinants in the D1 molecule responsible for this property are not known. The effect of fragment D1 on fibrinogen synthesis by the isolated perfused rat liver was studied using the (14C) carbonate method. Addition of 25 mg of fragment D1 to 100 ml of whole blood perfusate resulted in a significant increase in fibrinogen synthesis. When the C-terminal end of the gamma-chain of D1 was further plasmin-degraded to form fragment D3 this fibrinogen-enhancing effect was lost. Our studies suggest that the C-terminal of the gamma-chain of fragment D1 plays a role in regulating fibrinogen synthesis by the isolated rat liver.