Transplacental and milk transfer of polybrominated biphenyls to perinatal guinea pigs from treated dams

Abstract

Timed-pregnant albino Hartley strain guinea pigs of approximately 65 days gestation or lactating animals within 6–12 h of parturition received a single oral dose of Firemaster FF-1 (50 mg/kg body wt). The pregnant animals and their fetuses were killed 2 days later at term while the lactating animals and their pups were killed at intervals of 2, 4, 7, 14, 42, and 60 days. Tissues (liver, kidney, lung, perirenal fat) were removed for the analysis of the 2,4,5,2′,4′,5′-hexabromobiphenyl (HBB) isomer content by gal-liquid chromatography following extraction. Microsomes were prepared from samples of fresh liver for the analysis of hepatic mono-oxygenase ( p-nitro-anisole O-demethylase, aniline hydroxylase) and UDP-glucuronosyl-transferase activities. Transplacentally-acquired residues of the order of 45 μg HBB/g were found in both maternal and fetal adipose tissue and in fetal liver. HBB residues in maternal kidney, lung and liver were of the order of 4–7 μg/g while, in the fetuses and pups, levels in the kidney and lung were of the order of 1–2 μg/g. Levels of HBB in breast milk 2 days after treatment averaged 22.4 ± 7.8 μg/g (mean ± S.D.). A marked induction of hepatic microsomal mono-oxygenases was observed in guinea pig pups concomitant with elevated hepatic levels of HBB (9–19 μg/g) which decreased with time as the agent was redistributed into adipose tissue. By 7 days of age the pups had been weaned and by 14 days of age the enzymatic activities were comparable to those measured in control pups. HBB levels in the pup kidney, lung and adipose tissue reflected redistribution or sequestration in the body fat. The biological half-life of HBB in tissues of both dams and pups appeared to be approximately 22 days.