Properties and identification of rat liver cells in long-term cultivation

When cultured cells are used in experiments, It is very important to know from what kinds of cells the cultured cells are originated, and what characteristics the cultured cells maintain continuously in vitro Some properties of rat liver cells in long-term cultivation were examined for the purpose of identifying the cultured cells with parenchymal liver cells by investigating their functions. The production of rat serum albumin and α-globulin which is regarded as specific functions of liver parenchymal cells was detected in these cultured rat liver cells with the method of immunoelectrophoresis. Histochemically, acid phosphatase, glucose-6-phosphate dehydrogenase, succinic dehydrogenase, lactic dehydrogenase, and adenosine triphosphatase were demonstrated in the cultured rat liver cells which were morphologically epithelial. Alkaline phosphatase showed little activity in these cells. Glycogen was recognized by the periodic acid-Schiff technique, when bovine serum concentration in the culture fluid was reduced to 5 per cent. These histochemical findings of cultured rat liver cells were identical with those of parenchymal liver cells in vivo. These facts suggest that there is a possibility of the continuous cultivation of liver cells by the present methods and of the identification of the cultured cells with the parenchymal liver cells from their functions.