Vitamin K and the Synthesis of Factors VII-X by Isolated Rat Liver Cells

Abstract

Summary

Isolated liver cells from normal rats and from vitamin K-deficient rats injected with vitamin K continued to produce factor VII-X activities in vitro for at least 1.5 hr while cells from K-deficient rats showed little formation of factors VII-X. Both types of cells showed a sustained oxygen uptake for at least 1.5 hr before starting to decline. Cycloheximide and puromycin failed to inhibit vitamin K-dependent production of factor VII-X activities in surviving isolated liver cells. However, puromycin administered in vivo inhibited production of vitamin K-dependent factors VII-X in such liver preparations. Warfarin added to liver cells inhibited formation of factors VII-X but at the same time inhibited their oxygen uptake. It is suggested that vitamin K functions beyond the site of puromycin block in the formation of active factors VII-X.

This work was supported in part by NIH grant AM 10282.