Differences in tumor types and organ susceptibility in BALB-c and RF mice following dimethylnitrosamine and diethylnitrosamine.

Abstract

Summary Total doses of 300 mg/kg of dimethylnitrosamine (DMN) and 515 and 1010 mg/kg of diethylnitrosamine (DEN) were given to adult BALB/c mice in their drinking water. The oncogenic results for this strain were compared with previously reported data on a noninbred subline of RF/Un mice handled under similar conditions. DEN induced forestomach and esophageal squamous cell carcinomas in both strains but induced liver hemangiosarcomas in BALB/c mice and liver hepatomas in RF mice. In addition, DEN induced a high incidence of lung adenomas in the RF but was only slightly effective (3%) in BALB/c mice. In both strains, DMN induced lung adenomas and liver hemangiosarcomas. The liver sensitivity of both strains to DEN, in developing different tumor cell types between strains, suggests that different liver cells may metabolize DEN in the two strains and offers an excellent tool for metabolic studies. These carcinogens induced high incidences of tumors in the low-tumor-incidence BALB/c strain, with the exception of DEN, which had no oncogenic effect on the lung. Tissue sensitivity does not appear to relate directly to the spontaneous tumor incidence of the strain. No leukemogenic effect was observed following either DMN or DEN in either strain.