CANCER OF STOMACH AND PANCREAS IN GUINEA-PIGS INDUCED BY METHYLNITROSO-UREA AND -URETHANE

Methylnitroso-urea and-urethane, which induced carcinomas of the forestomach in rats after oral administration, have been tested in guinea pigs, since their stomach is glandular, like that of man. Both compounds were given in the drinking water 5 days weekly at a dosage of 2.5 mg per kg body weight. Methylnitroso-urea(I) produced malignant tumours in 12 out of 26 surviving guinea pigs and methylnitroso-urethane(II) in 27 out of 38. The medium induction time was 800 and 740 days respectively, and the localisation of the tumours was similar in both experiments. We observed 16 carcinomas and 2 sarcomas of the stomach, and 16 carcinomas of the pancreas, in 9 cases with metastases in other organs. In addition, with (I) one neurinoma, 2 malignant tumours of the ear duct, and 2 leucemias were obtained; with (II), one carcinoma of the lung and one of the larynx. The mechanism of action is briefly discussed. © 1968 Springer-Verlag.