The endoplasmic reticulum in regenerating liver cells.

Light-microscopic analysis of mouse liver homogenates six days after partial hepatectomy, showed a higher percentage of nuclei with adherent cytoplasm than homogenates from normal liver. This observation was true for animals with either a slow or rapid recovery of body weight after the operation. The phenomenon was not a function of the changes in the proportions of parenchymal and non-parenchymal tissue in the regenerating liver. Electron-microscopic analysis of random samples from normal and regenerating livers indicated an increase in the perinuclear rough endoplasmic reticulum, and a displacement of the glycogen depots within the regenerating cells six days after partial hepatectomy. The marked resistance towards homogenization, shown by the cytoplasm of the regenerating cells, may have been due to the observed increase of perinuclear membranes. However, qualitative changes of the cell membranes and a general decrease of proteolytic activity connected with liver regeneration may also have contributed.