Distribution and elimination of 14C-styrene in rat.

Male rats were exposed to about 45 ppm of radioactively labeled styrene in the inspired air for 1--8 h. The distribution and elimination of styrene and its metabolites in different organs and tissues were studied. To get an idea of the ratio between unmetabolized and metabolized styrene in organs and tissues, a supplementary study was performed in which five male rats were exposed to about 250 ppm of radioactively labeled styrene. The largest amounts of styrene and its metabolites were found in the subcutaneous fat, and the concentration displayed a sharp rise during the first 4 h of exposure in comparison with the following 4 h. The concentration of styrene and its metabolites in the cerebrum, cerebellum and muscles paralleled the arterial blood concentration throughout the entire period of exposure and amounted to about 70% of the arterial blood value. In the supplementary study an accumulation of styrene metabolites in subcutaneous fat was disclosed; it ranged from 15 to 20% during exposure.