Benzo[a]pyrene site of contact mutagenicity in skin of Muta™Mouse

Benzo[a]pyrene (BP) has been investigated for the ability to induce mutation at the site of contact. Skin painting treatments with BP caused a time-dependant and statistically significant increase in mutation frequency (MF) in the treated areas of skin. The MF exceeded 500X10(-6) 21 days after either 1X25 or 5X5 mu g treatments. Increases to >700X10(-6) were seen when doses of 1X50 or 5X10 mu g were used. Neither the liver nor the lung showed any increase in mutation frequency after 21 days in animals exposed to the 5X10 mu g treatment regime. It is concluded that following topical administration, BP is able to induce mutation in the skin at the site of application, but not in either the lung or liver.