[Unscheduled DNA synthesis (DNA-repair) within splenic and thymic cells of the rat under the influence of UV-light, X-irradiation and/or methyl-methanesulfonate (author's transl)].

Unscheduled DNA synthesis (UDS) of splenic and thymic cells of the rat has been stimulated in vitro by UV-light (8-128 J x m-2), X-rays (120-3480 rd), methyl-methanesulfonate (MMS), and/or a combination of UV-light and X-irradiation. The height of UDS-induced stimulation of incorporation of [3H]thymidine into splenic and thymic cell DNA at saturation doses of UV-light (splenic cells: 8, thymic cells: 96 J x m-2) or X-irradiation (splenic cells: 960, thymic cells: approximately 3480 rd) suggest that the greater sensitivity of T-cells (represented by thymic cells) towards UV-light and the greater sensitivity of B-cells (represented by splenic cells) towards X-rays can be explained-at least partly-in terms of less efficient excision repair systems.