Effect of the alkylating agent, dipin, on induced hepatocyte proliferation. II. An increase in the DNA synthesis period]

The alkylating drug dipin was injected to mice 2 hours before a partial hepatectomy. The duration of DNA synthesis of proliferating hepatocytes was determined by means of cytophotometry of DNA mass in the nuclei, labeled with 3H-thymidine 30 hours after the operation. The DNA mass was doubled simultaneously in diploid and tetraploid nuclei within 18-26 hours. The DNA in labeled nuclei of the control mice was doubled in 8 hours. The kinetics of 3H-thymidine incorporation at different stages of S-period was similar in alkylated and normal cells.