Metabolism of¹⁴C‐Pentachlorophenol in the Mouse

After subcutaneous or intraperitoneal injection of 14 C‐pentachloro‐phenol ( 14 C‐PCP) in the mouse (specific activity 1.6 μci/mg, dose 15–37 mg/kg body weight) the distribution of the activity in the body was determined by whole‐body autoradiography and by analysis of the individual organs after oxidation to 14 CO 2 . The highest specific activity was found in the gall bladder and its contents, the wall of the stomach fundus, the contents of the gastro‐intestinal tract and the liver. This shows that there is both a gastric and a biliary secretion of PCP and/or its metabolites, and excretion in the faeces. Most of the activity (72–83 %) was excreted in the urine in four days, about half of the dose in 24 hours. Only traces (< 0.05 %) were detected in the expired air. Identification and estimation of metabolites were performed by paper chromatography and isotope dilution techniques. All the urinary activity in the first 24 hours was due to PCP and probably tetrachlorohydroquinone. At least PCP was excreted in both the free and the conjugated form.