Role of 5-bromodeoxyuridine in the formation of sister chromatid exchanges in human lymphocytes exposed to gamma-irradiation at the presynthetic stage of the mitotic cycle

The formation of SCE was studied in human lymphocytes irradiated at the presynthetic stage of the cell cycle in the presence or absence of 5-bromodeoxyuridine. The results obtained showed that 5-bromodeoxyuridine present in the culture medium at the time of exposure or during the postirradiation period increased the yield of SCE. It is suggested that 5-bromodeoxyuridine exerts its effect through interfering with DNA repair.