[Ultrastructural-morphometric studies on the rat liver in the postnatal period. 1. Changes in the extrahepatocyte volume, the hepatocyte nuclei the cytoplasm and and the nucleus-cytoplasm ratio].

Quantitative changes in the volume densities of extrahepatocyte spaces, nuclei of hepatocytes, cytoplasm and of the nucleus-cytoplasm-ratio were studied in male Wistar-rats aged 0 (birth), 1, 2, 3, 4, 5, 6, 7, 14, 21, 28 days and 2, 3, 4, 5 and 6 months. The ratio of hepatocyte/nonhepatocyte fractions is 40.3 : 59.7 at birth and it increases to 86.6 : 13.4 by the 6th month. We observed 2 phases of proliferations of hepatocytes in the first 4 days, while the single volume of hepatocytes reaches lower levels. After the 4th day the single volume of hepatocytes increases because of the augmentation of volume density of cytoplasm. According to these changes the nucleus-cytoplasm-ratio will be reduced to 0.077 by the 5th month.