[Characteristics of the regeneration process in the liver deprived of polyploid hepatocytes].

By applying autoradiography with 3H-thymidine hepatocytes of young adult guinea pigs were found to enter the DNA-synthesis phase 25 hours after partial hepatectomy. Peaks of nuclei labeling were revealed 30, 45, and 60 hours after the operation. By calculating mitotic figures on squash preparations two waves of mitosis were found (in 40 and 55 hours) after hepatectomy. Cytophotometric study of DNA content showed practically all mononuclear and binuclear hepatocytes to contain diploid nuclei in 3 and 5 days after the operation. By the end of the 7th regeneration day there were revealed 6% mononuclear tetraploid cells. The percentage of binuclear cells during the period of regeneration under study decreased from 16 to 8%. A conclusion was drawn that the main cytologicalmechanism of the guinea pig liver regeneration was full-fledged mitosis ending by cell division.