3,3',4,4'-Tetrachlorobiphenyl. Excretion and tissue retention of hydroxylated metabolites in the mouse.

The coplanar 3,3',4,4'-tetrachlorobiphenyl (TCB) was given orally to mice and the metabolite patterns in feces, urine, liver, and adipose tissue were examined. In feces, 80% of the dose was excreted within 5 days. 5-Hydroxy-, 6-hydroxy-TCB, 4-hydroxy-3,3',4',5-tetrachlorobiphenyl, and unmetabolized TCB were identified by comparison to synthetic standards (GC/MS). 4-Hydroxy-trichlorobiphenyl and a dihydroxy-trichlorobiphenyl were indicated by the fragmentation pattern of the corresponding methylated derivatives by GC/MS. In urine, 4.9% of the TCB dose was excreted mainly as conjugates. After hydrolysis, TCB and seven hydroxylated metabolites were detected; 2-, 5-, and 6-hydroxy-TCB and 4-hydroxy-3,3',4',5-tetrachlorobiphenyl were identified and two dihydroxy-tetrachlorobiphenyls were indicated. The major compound detected after hydrolysis of urine was a dihydroxy-trichlorobiphenyl. TCB was the major compound present in the liver, while a minor portion was due to 4-hydroxy-3,3',4',5-tetrachlorobiphenyl. TCB, 4-hydroxy-3,3',4',5-tetrachlorobiphenyl, and 5- and 6-hydroxy-TCB were present in adipose tissue. In addition, radiolabeled material was present in a lipid fraction obtained after gel permeation chromatography of all samples except urine, indicating the presence of TCB metabolites with lipid characteristics.