Effect of 7, 12-dimethylbenz[
a]anthracene (DMBA) or 4-nitroquinoline, 1-oxide placed on the surface of mucosa of the glandular stomach combined with oral administration of N, N'-(2, 7-fluorenylene) bisacetamide (2, 7-FAA) or N-nitrosodiethylamine to male Donryu rats was studied in relation to the production of precancerous and cancerous lesions at the target area in the glandular stomach, as well as development of tumors in the liver and esophagus.
1) Many rats died of tumors of the liver and/or esophagus prior to the development of gastric carcinoma at the target area.
2) The lesions in the glandular stomach, i.e., scars and ulcers associated with or without heterotopic hyperplastic growth of glands, atypical glands, adenoma, polyp, carcinoma, and carcinosarcoma, were found only at the site of the focal treatment.
3) The lesions in the stomach were found in the highest rate in the group which received the local treatment with 4-nitroquinoline 1-oxide combined with the feeding of 2, 7-FAA. Combined treatment with DMBA and 2, 7-FAA or 4-nitroquinoline 1-oxide and N-nitrosodiethylamine also gave higher incidence of these lesions than the other treatments.
4) The local treatment with 4-nitroquinoline 1-oxide or DMBA placed on the surface of mucosa of the glandular stomach, which was performed at the beginning of the experiments, inhibited the development of tumors in liver caused by 2, 7-FAA feeding. The same treatment, however, did not inhibit the production of tumors in the liver and/or esophagus by the oral administration of N-nitrosodiethylamine.
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