[Effect of naproxen on the semiconservative DNA synthesis and DNA repair of various cell systems].

d-2-(6'Methoxy-2'-naphthyl)-propionic acid (naproxen) in different concentrations was investigated as to its influence on the semiconservative DNA synthesis and DNA repair of human lymphocytes and mouse speen cells. As could be shown, there was a slight diminuation of the DNA synthesis. In view of a desired antiproliferating effect in the treatment of rheumatic diseases this fact could certainly prove useful. Additionally, with a naproxen concentration of 30 ppm, a diminuation of the endonuclease activity in mouse spleen cells could be shown. With naproxen concentrations higher than 60 ppm a slight lowering of the exonuclease and polymerase activities in mouse spleen cells as well as in human lymphocytes were observed. With naproxen in a concentration of 120 ppm, all three enzymes of the excision repair investigated showed a distinct loss of activity. Results of investigations on ligase activity will be presented separately. Under the administration of naproxen, late effects on the genetic material are rather improbable, as long as the substance is not admininstered concomitantly with agents which have a direct effect on the DNA.