The rate of disappearance of 3:4-benzpyrene from the mouse after subcutaneous and intraperitoneal injection

Abstract

A study was made of the benzpyrene content of whole mice and of separate tissues and excreta, at varying intervals after subcut. and intraperit. injs. of the hydrocarbon, in amts. varying from 20-10,000 [gamma] per mouse. Benzpyrene disappeared about 15 times more rapidly from the perioneal cavity than from the subcutaneous tissues, the rate of disappearance from any one site being proportional to the logarithm of the conc. Carcinogenesis was more effective when inj. was by the subcutaneous route, so that persistence of the unchanged hydrocarbon seems necessary for the tumour induction. The change in fluorescence from violet to milky blue of the tissues at the site of inj. was traced to an impurity, not readily metabolized by the tissues, present in the originally injected benzpyrene. From a quantitative study of the benzpyrene content of different tissues and excreta, it is concluded that there is a continuous transfer of unchanged benzpyrene through the blood stream, with subsequent rapid destruction, less than 1% being excreted unchanged.