Control of prothrombin and factor VII biosynthesis by vitamin K

Abstract

The production of the plasma proteins, prothrombin and factor VII, which are essential in the blood clotting process, is dependent on the action of vitamin K. In intact vitamin K-deficient rats, administration of actinomycin D did not block the vitamin K-induced increase in plasma prothrombin. An isolated perfused rat liver preparation that released factor VII activity to the perfusate in response to vitamin K administration was developed. The factor VII production in this system was inhibited by puromycin but not by actinomycin D. These data indicate that the site of action of the vitamin is at some in step protein biosynthesis subsequent to the formation of a specific messenger RNA and prior to release of the complete protein from the liver.