[Analysis of the prereplicative period of liver regeneration in young mice. The fate of the hepatocytes in the DNA synthesis phase at the moment of surgery].

In the liver of young mice after partial hepatectomy the hepatocytes which entered S-phase prior to the operation complete DNA synthesis in time and their major part is arrested in G2-phase. During the second half of lag-period (12-24 h after the operation) about half of these cells enters mitosis. Another half of the hepatocytes which were in S-phase during the operation does not proceed to mitosis. The structure of the nuclei of these latter suggests the regression of premitotic preparation: some nuclei return to the initial G0-structure of the normal heterosynthetic hepatocyte (endoreproduction cycle) and others preserve the premitotic structure characteristic of S-phase. A number of morphological features approaches this latter subpopulation to S-nuclei of tumour cells of the mouse hepatoma No. 46. A suggestion is put forward that this subpopulation has lost its capacity for heterosythesis due to operation liver trauma.