Effect of Chlorpromazine on DNA Synthesis in a Cell Free System. ∗

Abstract

Summary

Addition of an extract of regenerating rat liver to a mixture of monophosphate nucleotides, in the presence of an energy generating system, was found to promote the incorporation of H³ thymidine into DNA. Addition of chlorpromazine and thioridazine to the enzyme protein suppressed the rate of incorporation of H³ thymidine. Other test drugs such as CPZ sulfoxide, promethazine, aspirin, amidopyrine, and diphen-ylhydantoin, did not affect this parameter. Addition of CPZ and other test drugs directly to the substrate did not affect incorporation of H³ thymidine. Thioridazine did so, to a moderate degree. Some biologic toxicity reactions of CPZ may be related to its anti-enzyme effect, possibly to its anti-DNA enzyme activity.