Benzo[a]pyrene-induced early alterations of the respiratory epithelium in the Syrian golden hamster.

Pathological alterations occurring in the epithelia of the trachea and the lobar and segmental bronchi of Syrian golden hamsters during a 20-week period of weekly BaP administrations were examined by means of light and electron microscopy. In the trachea these early changes included hyperplasia and squamous metaplasia. In the bronchi the development of small adenomas was observed, but no squamous metaplasia occurred.