[The nature of the lengthening of the G2 phase in the mitotic cycle of parenchymal cells of the mouse liver].

The phenomenon of G2 phase prolongation was found in the population of mouse hepatocytes. In normal postnatal liver growth, G2 phase prolongation in not pronounced and occurs in a small fraction of proliferating hepatocytes. In case of liver regeneration after removal of 2/3 of the organ, G2 phase prolongation is observed in a population of hepatocytes, which response to the proliferative stimulus first. Estimation of individual variation in expression of prolonged G2 phase along with the detailed analysis of the structure of the process of proliferation in the main population of hepatocytes (cells with normal G2 phase) allows to define the biological meaning of the "G2-population" observed. The prolongation of G2 phase may result from non-specific cell damage in mitotic cycles, caused by destruction of trophic relations in liver during its growth and regeneration.