Cytological and quantitative cytochemical changes in the hepatocyte population of newborn rats following hydrocortisone administration

Abstract

Changes have been assessed in cytological and quantitative cytochemical parameters of the hepatocyte population of newborn rats under glucocorticoid stimulation. Administration of hydrocortisone-acetate at the dose of 25 micrograms/g b.w./d during the 2nd week of postnatal life, caused: 1. an increase of the liver weight and of average dry mass, protein content, and volume of the hepatocytes; 2. a decrease of the number of hepatocytes per mg of liver tissue; 3. a reduction of the mitotic activity in liver parenchyma; 4. a gain in number of hepatocytes per liver lower than under normal conditions; 5. an increase of frequency of binuclear cells; 6. an increase of DNA-Feulgen per hepatocyte nucleus; 7. an increase per cell, greater than the mean protein increase per cell, in activity of arylhydrocarbonmonooxygenase and 7-ethoxycoumarin 0-deethylase, 2 enzymes dependent on cytochrome P-450. Induction of arylhydrocarbonmonooxygenase activity was prevalent in centrolobule. All the examined parameters, except that of DNA-Feulgen per nucleus and that of mitotic activity, changed strictly correlated with the duration of hormonal treatment. The values of a number of hepatocyte parameters (particularly: mean cell dry mass and volume, frequency of binuclear cells, enzymic activity) detected in the 12 d old rats after a 5 d long hormonal pretreatment, were in the range of those of animals 1 to 2 weeks older.