Morphological and biochemical changes induced in rat stomach by N-methyl-N'-nitro-N-nitrosoguanidine.

Morphological and biochemical changes reflecting the process of genesis of experimental stomach cancer were studied and compared in experiments carried out on 170 rats to whom N-methyl-N'-nitro-N-nitrosoguanidine had been given in drinking water. The concentration of the compound in drinking water was 167 mg/l. Malignization mostly developed during the ingrowth of the epithelial complexes involved in the process of carcinogenesis into the submucous membrane, in rare cases, into the mucous membrane itself. The results of experiments showed that biochemical changes preceded morphological alterations. The signs of inhibition of the synthesis of the isoenzyme spectrum of pepsinogen-pepsin revealed the qualitative changes of biochemical processes of the epithelium. A possible dependence of morphological features of the process of carcinogenesis on the evolutionally-established functional peculiarities of rat stomach epithelium is discussed.