Ultrastructural alterations of nonciliated cells after nitrosamine treatment and their significance for pulmonary carcinogenesis.

Syrian golden hamsters received multiple subcutaneous injections of N-diethylnitrosamine (DEN) or N-dibutylnitrosamine (DBN). Ultrastructural examination of the sequential alterations of bronchial epithelia was performed. Starting from the third to fourth treatment, the formation of lamellated inclusion bodies (LBs) was observed in nonciliated cells of segmental bronchi and peripheral bronchioles. These organelles closely resembled those LBs normally found in alveolar epithelial cells Type 2, which are a characteristic feature of alveolar cell carcinomas.