Determination of cocarcinogenic activity of benzo[e]pyrene for respiratory tract mucosa.
As benzo[e]pyrene (B[e]P) has been shown to enhance the carcinogenic effects of benzo[a]pyrene (B[a]P) on mouse skin [26], it therefore seemed important to determine if it would also act as a cocarcinogen in another target tissue, namely respiratory tract mucosa. Tracheal mucosa of rats was concomitantly exposed to B[a]P and B[e]P for up to 6 months. At B[a]P/B[e]P ratios of 1 : 1 and 0.5 : 1, B[e]P had no cocarcinogenic effects on tracheal epithelium. At the higher B[a]P/B[e]P ratio, B[e]P appeared to reduce the carcinoma incidence from 65% (B[a]P alone) to 40% (B[a]P plus B[e]P). In sharp contrast to the carcinoma incidence, the tracheal and peritracheal sarcoma incidence was enhanced 2-3-fold by B[e]P. Thus, while not cocarcinogenic for tracheal epithelium, B[e]P was cocarcinogenic for connective tissue. Together with other results [26], these point to the importance of the target tissue as a determining factor of cocarcinogenic activity of test substances.
D000818:Animals; D001580:Benzopyrenes / Q000378:metabolism / Q000633:toxicity*; D002277:Carcinoma / Q000139:chemically induced; D005260:Female; D009092:Mucous Membrane / Q000187:drug effects; D009374:Neoplasms, Experimental / Q000139:chemically induced; D051381:Rats; D011916:Rats, Inbred F344; D012142:Respiratory Tract Neoplasms / Q000139:chemically induced*; D012513:Sarcoma, Experimental / Q000139:chemically induced; D014134:Tracheal Neoplasms / Q000139:chemically induced
D001580:Benzopyrenes