Cytophotometric Study of Deoxyribonucleic Acid in Cortisone-Treated Rat Hepatocytes

Abstract

Rats were treated by intramuscular injection with cortisone acetate, 25 mg/day for 5 days. Small pieces of liver obtained from treated and normal animals were squashed on a microscope slide so as to obtain many areas only a single cell in thickness. After Feulgen staining to demonstrate DNA, optical density was measured using a projection technique. In both the normal and treated animals the nuclei were easily segregated in 3 ploidy classes, diploid, tetraploid, and octaploid, depending upon Feulgen intensity. In all 3 classes, the absorbence of nuclei from cortisone-treated animals was approximately 20% lower than the normal. These data were interpreted to indicate that a change in DNA content had been induced by cortisone administration. These findings are comparable to data obtained from similar animals using chemical methods for the determination of DNA.