Metabolism of 2,4'5-trichlorobiphenyl: enrichment of hydroxylated and methyl sulphone metabolites in the uterine luminal fluid of pregnant mice.

Autoradiography of 2,4',5-trichloro-[14C] biphenyl ([14C] triCB) in mice at different stages of gestation indicated a strong accumulation of radioactivity in the uterine luminal fluid at gestation day 9 and later. From day 10 an uptake of radioactivity occurred also in the yolk sac epithelium. In order to identify the suspected metabolites in the fluid pregnant mice were dosed with unlabelled triCB on gestation day 9. Gas chromatographic (GC) and mass fragmentographic (MF) analysis of extracts of uterine fluid obtained on day 12 showed that hydroxylated, methyl sulphone and conjugated metabolites were present in the fluid. The unchanged triCB could not be detected in the extracts of the fluid. The site of release of the metabolites to the fluid may be the endometrium or, possibly, the yolk sac epithelium. The mechanism behind the concentration of water-insoluble methyl sulphone and hydroxylated metabolites of triCB in an aquatic phase is discussed.