[Induction of tumours by different endogenously formed N-nitroso-ureas in the hooded rat (author's transl)]. / Tumorinduktion durch verschiedene endogen gebildete N-Nitroso-Harnstoffe bei der Haubenratte

By means of application of methyl-, ethyl-, n-propyl-, iso-propyl- and n-butylurea together with sodium nitrite the formation of corresponding carcinogenic N-nitroso compounds is demonstrated. The transplacental action of endogenously formed ethylnitrosourea led to a characteristic spectrum of tumours in the offspring comprising mainly neurogenic neoplasms of the brain and Nn. trigemini. The tumour incidence is especially high after application of precursors (ethylurea and nitrite) with the food. In postnatal experiments with methylurea and nitrite, there were induced mostly neurogenic tumours and reticulum cell sarcomas of the paracoecal region. A similar spectrum of tumours was found after postnatal application of iso-propylurea and nitrite by gastric tube. After a single dose of iso-propylurea and nitrite at day 21 of pregnancy there seems to be a slight carcinogenic effect in a small group of animals. The application of n-propylurea and n-butylurea, resp., together with nitrite led mainly to reticulum cell sarcomas of the paracoecal region after formation of corresponding alkylnitrosoureas. The spectrum of tumours is compared with that after the action of complete carcinogen and with the results obtained by other authors.

[Lack of a cancerogenic effect after application of amines and amides together with nitrite in rabbits (author's transl)]. / Fehlender kanzerogener Effekt nach Gabe von Aminen bzw. Amiden und Nitrit an Kaninchen

Young rabbits of both sexes received the following nitrosable compounds and sodium nitrite: Group 1:13 animals received 0.1 per cent methylurea in food and 0.1 per cent NaNO2 in drinking water. Two control groups of 6 rabbits were applied NaNO2 or methylurea, respectively. Duration of application 100 days. Group2: 20 animals received 0.2 per cent dimethylbenzylamine in drinking water and 0.15 per cent NaNO2 in food for 100 days. 10 control animals got only 0.2 per cent dimethylbenzylamine. Group 3: 20 rabbits were fed with 0.2 per cent diethylaminohydrochloride and 0.2 per cent NaNO2 added to the food. 10 controls received only 0.2 per cent of the amine. Duration of feeding 63 days.