[Induction of tumors of the stomach in mini-pigs by methylnitrosourea administration (author's transl)].

The oncogenic effect of N-methyl-N-nitrosourea was studied in Hanford miniature-pig. The compound - dissolved in 0,9% NaC1 (pH 6,1 - 6,2) and supplemented with 1% NaH2PO4 - was administered per os to the animals in intervals of two weeks during 4,5 years. Finally the animals, which had behaved clinically inapparent during the whole run of the experiment, were sacrificed and autopsied. All animals of the experimental group had developed stomach tumours, whereas control animals showed normal conditions of gastric mucosa. Except one, all tumours were grouped macroscopically as multiple, exophytic, papillary, cauliflower-like neoplasms of the mucosa, located predominantly within cardia- and fundus-regions. Histologically they are to be classified generally aal characteristics of an early malign dedifferentiation. One - above excepted - tumour proably belongs to the class of malign neurinomas. The results of the experiment demonstrate in general that the obvious organotropic properties of certain oncogenic nitrosamides might be in a way also species-depending ones. This perception seems to be important in view of morphogenesis as well as of etiopathogenesis of stomach tumours.