Diminution of chemically induced lung neoplasia in mice by phenobarbital pre-treatment.

ABSTRACT

Pre-treatment of 21-day-old ICR/Jcl mice with 75 micrograms/g of phenobarbital significantly reduced the yields of lung tumors induced by 4-nitroquinoline-1-oxide (4NQO) and furylfuramide. Dimethylbenz[a]anthracene (DMBA)- and urethane-induced lung tumorigenesis was also reduced, but was not significantly different from that in mice receiving only the carcinogen. However, 6 consecutive treatments with phenobarbital (40 micrograms/g) in adult mice greatly reduced urethane-induced lung tumorigenesis. Post-treatment with an equal dose of phenobarbital showed neither diminution nor enhancement of tumorigenesis.