Ultrastructural and metabolic studies of isolated and cultured hepatocytes.

Cells isolated from adult rat liver form distinct cell populations: the parenchymal cells or hepatocytes and the non-parenchymal cells, mainly endothelial and Kupffer cells. These two groups are easy to separate by centrifugation methods, including centrifugal elutriation. The single-cell suspension of hepatocytes seems to be constituted of subfractions which are located roughly in the centrilobular and perilobular regions of the liver lobule and are differentiated so that they form cell lines with distinct metabolic activities. The basic means of characterizing the isolated hepatocytes consists of determining their size distribution, their sedimentation and elutriation properties, and their metabolic activities. Cultures of hepatocytes offer the possibility of prolonging their survival and of studying the differentiation of new bile canaliculi and the reconstitution of biliary polarity in the cytoplasm. The combination of Kupffer cells with hepatocytes improves the culture condition, as a result of elimination of cell debris by phagocytosis by the non-parenchymal cells. The application of the isolation and partition methods to pre-neoplastic liver allows us to classify the cells according to their degree of hyperplasia and opens up a new field of investigation.