[Influence of some cytostatic drugs on semiconservative DNA-synthesis and DNA-repair in normal and cancer cells (author's transl)].

The action of cyclophosphamide, vincristine, vinblastine and procarbacine on the enzymes of the excision repair and on the semiconservative DNA-synthesis was investigated. To get a view of the total repair enzyme complexes the incorporation of 3H-thymidine into DNA after UV- and Gamma-irradiation was measured, and sedimentation profiles in alkaline sucrose were carried out. The drugs were also tested after being metabolized. The 4 drugs had no influence in an in vitro system on DNA-repair using spleen cells. Vinblastine and procarbacine showed an inhibitory effect on semiconservative DNA-synthesis. Using Yoshida ascites cells for the investigations we found an inhibition of the exonuclease-polymerase system by cyclophosphamide and procarbacine and a supression of ligase reaction by vinblastine and vincristine. Different degrees of inhibition of DNA-synthesis in Yoshida ascites cells could be seen after use of the 4 cytostatic drugs.