GROWTH-PATTERNS OF RAT HEPATOCYTES DURING POSTNATAL-DEVELOPMENT

Abstract

During postnatal growth in rat liver, a characteristic shift towards binuclear cells and cells of higher ploidy class occurs. When the protein content of individual isolated hepatocytes of different ploidy classes is analyzed cytophotometrically using the specific protein stain Naphthol Yellow S, the growth in mass in the period 30-99 days is due mainly to an increase of protein content of binuclear diploid (BD) and mononuclear tetraploid (MT) cells. The mononuclear diploid (MD) cells play a quickly-diminishing role in the parenchymal population after the initial growth phase, and cells of highest ploidy degree remain quantitatively unimportant. The quick-growing BD and MT cells reach a Naphthol Yellow S-protein value twice that of MD cells only after a certain period of growth; changes in protein content are slight or absent from 99 days onwards in all cell types investigated.