Morphological investigations on co-cultures of rat hepatocytes and the neonatal liver cell line RL 19.

: Hepatocytes isolated from mature rats were cultivated together with proliferating liver cells derived from newborn rats (RL 19 line). The hepatocytes of the co-cultures were viable for long period and preserved their glucose-6-phosphatase activity and glycogen content longer than the mature rat hepatocytes cultured alone. Electron microscopy revealed that the RL 19 cells were covering the hepatocytes and growing beneath them. Both the RL 19 cells and the adult hepatocytes established tight contact with each other, but between the two cell types there was always a gap bridged by microvilli and resembling Disse's space. It is assumed that the envelope formed by the RL 19 cells may have a role in the maintenance of the differentiated hepatocyte structure.