Increased biopterin production in rats with tumors induced by radon inhalation and benzonaphtoflavone administration

Abstract Serial determinations of urinary biopterin were performed in rats during the development of lung tumors induced by radon inhalation and 5,6-benzonaphtoflavone admini-stration. A striking increase in biopterin levels was observed in animals which developed single or multiple epidermoid carcinoma of the lung and this increase occurred several weeks before tumors could be detected radiographically.