Lack of Carcinogenic Sensitivity of the Glandular Stomach in Heterozygous p53 Knockout Mice Given N-Methyl-N-Nitrosourea in their Drinking Water for 26 Weeks.

Gastric tumorigenic sensitivity to N-methyl-N-nitrosourea (MNU) was examined in heterozygous p53 knockout (p53(+/-)) CBA mice and their wild-type littermates (p53(+/+)). In Experiment 1, 37 male p53(+/-) or 38 male p53(+/+) CBA mice were given MNU in their drinking water at concentration of 50ppm (Group 1 or 4), 10ppm (group 2 or 5) or 0ppm (group3 or 6) for 26 weeks. In Experiment 2, p53(+/-) and p53(+/+) CBA mice of both sexes received water containing 50ppm MNU for 26 weeks.

Enhancing effects of oltipraz on the development of spontaneous hepatic lesions in LEC rats.

Oltipraz, developed as an antischistosomal agent, protects against the hepatotoxicity of many xenobiotics and is known to be an effective inhibitor of experimental carcinogenesis in rodents. In the present study, we investigated its effects on the development of lesions in LEC rats, established as a mutant strain characterized by a hereditary predisposition for hepatic damage with severe jaundice. A total of 35 male 6-week-old LEC rats were divided into 2 groups, one administered diet supplemented with oltipraz at a dose of 400 ppm, and the other fed basal diet alone.