Synergistic Effects of Diethylnitrosamine and Different Dusts on Respiratory Carcinogenesis in Hamsters¹ Available to Purchase

A possible synergistic action between the carcinogen diethylnitrosamine injected s.c. and MgO, Al₂O₃, or carbon instilled intratracheally in the respiratory tract of Syrian golden hamsters was studied. Diethylnitrosamine alone induced tumors of the nasal cavity in 50% of the animals. Tumors were also produced in the larynx and trachea but not in the lungs. Groups receiving weekly intratracheal instillations of 0.9% NaCl solution suspensions of carbon or Al₂O₃ had no tumors of the respiratory system. MgO alone induced a significantly large number of lymphomas of the histiocytic type that were not induced by diethylnitrosamine and MgO. In the groups receiving diethylnitrosamine followed by intratracheal instillations of dust-0.9% NaCl solution suspensions, the tumor incidence in the upper respiratory tract was similar to that seen with diethynitrosamine alone, but lung tumors were also observed. Intratracheal instillations of 0.9% NaCl solution after diethylnitrosamine also caused a number of tumors to occur in the lower respiratory tract.

It can be concluded that carbon and Al₂O₃ are not carcinogens for the respiratory system of hamsters. The increase in incidence of lower respiratory tract tumors previously seen with diethylnitrosamine followed by Fe₂O₃ and 0.9% NaCl solution was here obtained with diethylnitrosamine followed by 0.9% NaCl solution alone.