3,3′,4,4′-Tetrachloro[¹⁴C]biphenyl in pregnant mice: enrichment of phenol and methyl sulphone metabolites in late gestational fetuses

Abstract

1. The distribution of radioactivity after injection of 3,3′,4,4′-tetrachloro[¹⁴C]biphenyl (¹⁴C-TCB) in pregnant mice was determined by autoradiography and computer-assisted densitometric analysis. TCB metabolites in fetal tissue were analysed by g.l.c. and g.l.c.-mass spectrometry and compared to the synthesized reference compounds 2-, 5- and 6-methoxy-3,3′,4,4′-tetrachlorobiphenyl.

2. The concentration of radioactivity was high in the uterine fluid, and in the fetuses in late gestation. Fetal radioactivity decreased after pretreatment with a high dose of unlabelled TCB. Radioactivity was reversibly bound to fetal tissues.

3. A phenolic metabolite, 3,3′,4,4′-tetrachloro-2-biphenylol, and a methylsulphonyl-tetrachlorobiphenyl were found in fetuses in late gestation. No unmetabolized TCB was detected in the fetuses.

Key Words:

• ¹⁴C-labelled
• disposition
• fetal accumulation
• metabolism
• methylsulphonyl-3,3′,4,4′-tetrachlorobiphenyl mouse polychlorinated biphenyls (PCB)
• 3,3′,4,4′-tetra-chlorobiphenyl
• 3,3′,4,4′-tetrachlorobiphenylol