Induction of squamous cell carcinoma in the oral cavity of the rats by oral administration of 4-nitroquinoline 1-oxide in the drinking water

The influence of concentration of carcinogen

Abstract

4-nitroquinoline 1-oxide added to drinking water at three concentrations (10ppm, 25ppm, 50ppm) was administered to 45 male S-D strain rats for 7 months. Major findings were as follows.
1) Squamous cell carcinomas appeared earlier in 25ppm and 50ppm groups as compared to 10ppm group.
2) The carcinomas were most frequently observed in 50ppm group with highest incidence of infiltrating tumor as well.
3) Ulcerating carcinomas more frequently appeared in higher concentration groups.
4) The historogical type of carcinoma was almost identical in all groups examined.
5) No metastasis was observed in any treatment groups examined.
6) No malignant neoplasma was observed in any other organs except for oral cavity.