[Increase in DNA repair after treatment of mice with N-methyl-N-nitrosourea]

Inbred Balb/C mice were treated in vivo for three days with ip injections of the carcinogen N-Methyl-N-nitrosourea (25 mg/kg body weight). Reported data show that the spleens from treated animals are strongly reduced, functionally impaired and that they present a higher capacity of repairing their DNA after damage exerted in vitro by the same carcinogen or by ultraviolet rays (900 ergs/mm2).