Prothrombin synthesis in the dog

¹ Department of Physiology and Pharmacology, Wayne State University, College of Medicine, Detroit, Michigan

Liver parenchymal cells were found to be the sites for production of prothrombin. Dogs were employed and their rate of prothrombin synthesis was modified as desired by giving either Coumadin or vitamin K₁. The fluorescent antibody technique was found a valuable aid in evaluating liver cell function. Under normal conditions there is periodic synthesis of prothrombin with only 10% of the parenchymal cells actively participating at any one time. Prothrombin-deficient or normal dogs can be stimulated to more vigorous activity by giving vitamin K₁. In such circumstances all the liver parenchymal cells were able to synthesize prothrombin. A regulatory mechanism promotes either synthesis, storage, or release of prothrombin by liver parenchymal cells. No other cell types of the liver, spleen, or bone marrow appeared capable of synthesizing prothrombin.

Key Words: hepatic origin of prothrombin • liver parenchymal cell synthesis of prothrombin • prothrombin storage in liver parenchymal cell • fluorescent antibody technique for study of dog prothrombin synthesis • vitamin K₁ stimulation and regulation of prothrombin production • Coumadin inhibition of prothrombin synthesis • intracellular prothrombin • synthesis • prothrombin storage by hepatocytes

Submitted on September 20, 1963