EFFECT OF PHENOBARBITAL ON THE DEVELOPMENT OF TUMORS IN MICE TREATED NEONATALLY WITH N-ETHYL-N-NITROSOUREA

  • 1 January 1982
    • journal article
    • research article
    • Vol. 73  (1) , 111-114
Abstract
The effect of phenobarbital on the development of neurogenic tumors induced in mice by neonatal administration of N-ethyl-N-nitrosourea (ENU) was studied. A total of 185 A/He mice was divided into 4 groups. Continuous oral administration of phenobarbital (0.05%) in drinking water was commenced 4 wk after birth in group 1. A single injection of 40 mg/kg of ENU was given s.c. on the back within 24 h after birth in group 2. After neonatal injection of ENU, phenobarbital was commenced 4 wk after birth in group 3. Group 4 was the untreated control. The experiment was terminated 12 mo. after birth. The serum level of phenobarbital at the end of the experiment was 8.7 .mu.g/ml in group 1 and 7.0 .mu.g/ml in group 3. Neurogenic tumors were induced only in groups treated with ENU. The incidence was 5.7% in group 2 and 10.9% in group 3 although the difference between the 2 groups was not statistically significant. A total of 3 tumors (3.0%) was induced in the CNS and 5 tumors (5.1%) in the peripheral nervous system. Histologically, the former were oligodendroglioma and the latter were schwannoma. Lung tumors, lymphomas and hepatic tumors were also induced by ENU, and in male mice phenobarbital had a suppressing effect on the development of liver tumors.