CELL SIZE, NUCLEAR CONTENT, AND THE DEVELOPMENT OF POLYPLOIDY IN THE MAMMALIAN LIVER

Abstract

Isolated parenchymal cells were prepared from livers of mice, rats, and human beings. The sizes of cells of various ploidy classes were determined, and cell size was found to be directly proportional to cell ploidy. These results are compatible with the operation of gene dosage in the control of the rates of synthesis of cell constitutents in polyploid liver cells. The growth of the liver of the Swiss mouse has 3 major phases: the multiplication of diploid cells; the formation of a large population of binucleate cells with diploid nuclei; and, an increase in cell size, principally by poly-ploidization of the nuclei, with the proportions of mononucleate and binucleate cells remaining constant. No obvious advantage, except possibly a reduction in total cell surface area, accrues to the animal as a result of the process of cell polyploidization.