EXPRESSION OF COAGULATION FACTOR-V GENE BY NORMAL ADULT HUMAN HEPATOCYTES IN PRIMARY CULTURE

Normal human adult hepatocytes were examined for their ability to synthesize and secrete factor V using primary culture. The culture medium contained both factor V and factor Va as determined by bioassay and activation experiments. Immunoprecipitation of newly synthesized labelled factor V showed the presence of both native factor V (m.w. 330 000) and two fragments of respective molecular weight 300 000 and 265 000. Northern blot analysis revealed the presence of a single 7 kb factor V mRNA in cultured human hepatocytes as in liver biopsies, together with fibrinogen beta and albumin transcripts. Relative levels of factor V, fibrinogen beta and albumin mRNAs differed when the cells cultured, suggesting that expression of the three corresponding genes might in part be independently regulated. Furthermore, addition of glucocorticoids enhanced factor V and fibrinogen beta mRNA levels 1.6- and 5-fold respectively, but did not significantly increase that of albumin. These results provide evidence that human hepatocytes actively participate in the synthesis of plasma factor V and constitute a valuable model to study the common and specific regulations involved in the control of the expression of this gene in human liver.