Activation of collagen synthesis in primary culture of rat liver parenchymal cells (hepatocytes).

An increase in collagen synthesis by hepatic parenchymal cells (hepatocytes) was observed during 8 days in primary culture by the quantification of total [3H]hydroxyproline as a marker of total collagen synthesis and the ratio of [3H]hydroxyproline in the high-molecular-weight fraction to total [3H]hydroxyproline as a marker of collagen degradation after incubation of the cells with [3H]proline for 24 h. Type analysis of the collagen produced by the cells after 8 days in culture showed the presence of type I and type III collagens in addition to the components corresponding to type IV and type V (alpha A and alpha B) collagens. Only the latter two types were found in the collagens produced by the cells after 2 days in primary culture. The purity of the hepatocytes inoculated was 97%, and the majority of the contaminating small cells were erythrocytes. The rate of serum albumin synthesis, which is a typical function of the hepatocytes, was constant or increased during the culture period. Immuno-electron microscopic observation indicated the production of type I collagen by the hepatocytes after 8 days in primary culture. These results are explained only by the activation of collagen synthesis in the day-8 hepatocytes in primary culture.