Pulmonary tumorigenesis in Syrian golden hamsters after intratracheal instillations with automobile exhaust condensate.

Syrian golden hamsters were intratracheally instilled once every two weeks for life with automobile exhaust condensate (AEC) at two dose levels. The condensate was prepared from the most common German passenger car driven in the Europa-Test cycle (simulated city driving) and contained 340 microgram/g benzo(a)pyrene (B(a)P). Despite the very low total dose of B(a)P received, all animals of both dosage groups developed multiple pulmonary adenomas. Electron microscopy revealed these tumors to resemble B(a)P induced pulmonary adenomas in their ultrastructure. Numerous condensate-laden macrophages in tumor and peripheral lung tissues indicated that little of the instilled condensate had been removed from the airways through mucociliary action.