[Effects of the method and regimen of administration on the carcinogenic effect of N-methyl-N'-nitro-N-nitrosoguanidine in rats].

Peculiarities of carcinogenic effect of N-methyl-N'-nitro-N-nitrosoguanidine administered through a stomach tube on rats were studied in 30 rats given 1-2 ml MNNG dissolved in distilled water (5 mg/ml) through a gastric tube for 2-3 days. The procedure is repeated every 4-10 days. This intermittent carcinogen administration continued until week 20; the animals were killed on week 25. All effective 26 (100%) rats had multiple papillomas and squamous cell carcinomas of the forestomach, 5 (19.2%) had adenomatous hyperplasias and adenocarcinomas of the glandular stomach, 7 (26.9%) had adenocarcinomas and sarcomas of the small intestine.