Comparative study on the carcinogenicity of N-nitrosodiethylamine and benzo[a]pyrene to the lung of Syrian golden hamsters induced by intermittent instillations to the trachea.

N-Nitrosodiethylamine (NDEA) and benzo[a]pyrene (B[a]P) were intratracheally instilled into female Syrian golden hamsters 15 times weekly for about 4 months. The total dose given was 15 mg. The control hamsters were given only phosphate buffer solution. During the total life span, tumor incidence rates in the NDEA and B[a]P groups were 100% and 46%, respectively, and no tumor developed in the controls. We concluded that the high rate of carcinogenicity of NDEA seen in the respiratory organs of Syrian golden hamsters must be given increased attention.