Carcinogenic response of the respiratory tract of Syrain golden hamsters to different doses of diethylnitrosamine.

Abstract

Summary Four groups of adult male Syrian golden hamsters received 12 weekly subcutaneous injections of diethylnitrosamine (DEN), each at the dose of 4.0, 2.0, 1.0, and 0.5 mg respectively. The marked carcinogenic effect of DEN on the respiratory tract was confirmed. In addition, the present results clearly demonstrate a positive dose-response correlation for tumor induction in the upper respiratory tract (nasal cavities, larynx, and trachea). The neoplastic response in the lower respiratory tract (bronchi, bronchioles, and alveoli) remained very low in all 4 experimental groups. Nasal cavity tumors developed early and reached incidences varying from 17 to 75%. They included squamous cell papillomas, squamous, adeno-, and anaplastic carcinomas, as well as neuroepithelial tumors. Tumors of the larynx reached incidences of 17 to 72%, and tumors of the trachea incidences of from 88 to 100%; laryngeal and tracheal tumors were mostly multiple polyps and papillomas. Tumors in the stem bronchi were rare and histologically similar to the tracheal tumors. Only 3 tumors of the lung were observed in a total of 142 animals, and they had adenomatous structures. In addition, a few peripheral proliferative lesions occurred in the pulmonary parenchyma. The present results demonstrate that the carcinogenic response of the Syrian golden hamster to DEN follows distinct patterns for the different segments of the respiratory system.