This amended application is based on the hypothesis that an electrophilic metabolite, quinone methide, and free radical metabolites, including the butylated hydroxytoluene(BHT) phenoxyl radical, are involved in both the pulmonary toxic and carcinogenic responses elicited by BHT. Additionally, it is proposed that these processes can be enhanced through a novel mechanism of chemical-chemical interactions. In this regard, the investigators will (1) characterize by electron spin resonance spectroscopy the free radical intermediates, generated from BHT and its metabolites, (2) investigate the metabolic activation of BHT to quinone methide using UV/VIS spectroscopy and HPLC, (3) assess the ability of pharmacologic and environmental chemicals to enhance the activation of BHT to electrophilic and radical intermediates, and (4) examine whether another phenolic antioxidant, butylated hydroxyanisole, enhances the lung tumor promoting activity of BHT. The in vitro studies characterizing the activation of BHT will utilize model chemical and enzyme systems, cells isolated from target organs and lung slices.
