Enhancement of lung tumor formation in mice.

There is now a great deal of data available that show that BHT enhances the development of lung tumors in mice. In many ways BHT behaves like a promoting agent. Interestingly, it also has tumor enhancing or promoting properties in other organs than mouse lung, such as rat liver, rat bladder, possibly rat GI tract, and in in vitro systems. The development of lung tumors by BHT may be influenced by comparatively low exposure regimens; the minimum dose found so far to be effective is 6 intraperitoneal injections of 50 mg/kg of BHT of feeding a diet containing 500 ppm of BHT for 2 weeks. While these findings seem to require that the continued use of BHT as a food additive needs to be reevaluated, it should be mentioned that other considerations have led to the conclusion that the use of BHT probably has a large margin of safety. This makes it important to establish the mechanism of action of BHT which at this time remains unknown.