[Polyploidy in the human liver normally and in hepatitis]

DNA contents in mono- and binucleated hepatocytes have been measured using cytofluorimetry on slides of isolated human liver cells. In all, 28 patients, with the mean age of 33.7 years (ranging from 17 to 50 years), were examined, including both healthy (normal) ones and those with chronical hepatitis. The normal livers were shown to include approximately 88% of mononucleated diploid hepatocytes, and 9% of binucleated hepatocytes with diploid nuclei, whereas mononucleated tetraploid cells, binucleated cells with tetraploid nuclei and mononucleated octaploid cells made all together only a bit slightly more than 3%. The patients with hepatitis displayed markedly increased numbers of binucleated hepatocytes with diploid nuclei; some of these having more than 40% of such cells. The number of mononucleated tetraploid hepatocytes, binucleated hepatocytes with tetraploid nuclei and of mononucleated octaploid hepatocytes was seen to increase very slightly not reflecting the degree of the liver disease. It has been proposed that the normal and the reparative growth of human liver is accomplished due mainly to mitotic divisions of mononucleated diploid hepatocytes; the role of polyploidy in these processes being insignificant.