Promoting effect of polybrominated biphenyls on tracheal papillomas in Syrian golden hamsters.

Male Syrian golden hamsters were used for an initiation-promotion study of respiratory tract carcinogenesis. Hamsters were given a single subcutaneous dose of 0 or 80 mg N-nitrosodiethylamine (NDEA)/kg body weight and were fed diets containing 0 or 100 mg polybrominated biphenyls (PBB)/kg diet for 140 d. Basal diet was fed from d 140 until the end of the experiment on d 273. The number of tracheal papillomas was significantly increased in hamsters given NDEA and PBB as compared to those in hamsters given only NDEA. Tracheal papillomas were not seen in untreated hamsters or in those not given NDEA and fed diets containing PBB. Nasal tumors occurred at approximately the same incidence in hamsters given NDEA as in those given NDEA and PBB. Results indicate that PBB may promote the development of tracheal papillomas in the hamster.