Effects of radiation on murine T-cell leukemogenesis induced by butylnitrosourea.
BDF1 mice were exposed to butylnitrosourea for 12 weeks (BNU, 0.02% in the drinking water) and died of thymic lymphomas with median latency periods of 12-20 weeks. In addition to BNU, groups of mice received weekly radiation doses of 0.0625-1.0 Gy; 12 X 0.25 Gy enhanced leukemogenesis, 12 X 0.75 Gy delayed it and 12 X 0.50 Gy had no effect. Lower doses had marginal enhancing effects. After a dose of 12 X 1.0 Gy, the mice died earlier than after treatment with BNU alone and, as with 12 X 0.75 Gy, some extrathymic lymphomas were observed. The numbers of CFU-S in the femur and the spleen showed a dose-dependent depression, in addition to the effect of BNU alone. In lymphocyte stimulation assays with Con A und LPS and also in the mixed lymphocyte reaction, a reduced proliferation was found, again dependent on the radiation dose. Therefore, there was no correlation of leukemogenesis and the degree of stem-cell reduction or depression of these immune parameters. The delay of leukemogenesis by 12 X 0.75 Gy in addition to BNU may be caused by an enhanced target cell kill.
D000818:Animals; D003043:Cocarcinogenesis; D003114:Colony-Forming Units Assay; D004307:Dose-Response Relationship, Radiation; D005260:Female; D007942:Leukemia, Experimental / Q000139:chemically induced*; D007953:Leukemia, Radiation-Induced; D051379:Mice; D009607:Nitrosourea Compounds; D013601:T-Lymphocytes / Q000528:radiation effects
D009607:Nitrosourea Compounds; C002738:N-nitrosobutylurea