Exposure of human lymphocytes to ionizing radiation reduces mutagenesis by subsequent ionizing radiation

• Published in: Mutation Research/Environmental Mutagenesis and Related Subjects Vol. 164; no. 6; pp. 347 - 351
• Main Authors: Sanderson, B.J.S., Morley, A.A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.1986
• Subjects: Cell Survival - radiation effects; Cells, Cultured; DNA Replication - radiation effects; Dose-Response Relationship, Radiation; Humans; Hypoxanthine Phosphoribosyltransferase - genetics; Hypoxanthine Phosphoribosyltransferase - radiation effects; Lymphocytes - cytology; Lymphocytes - drug effects; Lymphocytes - radiation effects; Mutagens; Mutation; Thioguanine - toxicity; Thymidine - metabolism
• ISSN: 0165-1161; 0027-5107
• DOI: 10.1016/0165-1161(86)90027-0

The effect of prior incubation with [ 3H]thymidine on survival and mutagenesis after X-irradiation of human lymphocytes was studied by incubating lymphocytes with 0.001–1.0 μCi/ml [ 3H]thymidine for 6 h at 37° C and then irradiating with 150 or 300 rad. Survival was measured using lymphocyte cloning and mutagenesis was measured using 6-thioguanine selection to detect clones mutated at the hypoxanthine phosphoribosyltransferase locus. [ 3H]Thymidine alone had no effect on survival or mutagenesis and X-radiation alone produced the expected decrease in survival and increase in mutations. [ 3H]Thymidine prior to X-radiation had no effect on lethality of X-radiation but at concentrations of 0.1 and 1.0 μCi/ml produced a significant decrease in the number of mutations induced after both 150 and 300 rad. The results suggest that ionizing radiation, produced by disintegration of 3H, reduces the mutagenic effect of a subsequent exposure to ionizing radiation by induction of a system which prevents or repairs a restricted class of radiation damage.