Residual effects of polybrominated biphenyls following perinatal exposure in rats

Abstract

Polybrominated biphenyls (PBBs) undergo transplacental movement and have been detected in milk. Since most PBBs are biologically stable and very slowly eliminated, exposed offspring may have significant body burdens of certain PBB congeners throughout their lifetime. Therefore, the persistence of effects of perinatal exposure to PBBs on liver and kidney morphology, microsomal enzyme activity and concentration of PBBs was determined. Rats were fed diet containing 0 or 100 ppm PBBs (Firemaster BP-6) from the eighth day of pregnancy through 28 days postpartum. All pups were then weaned onto a diet free of PBBs. Experiments were conducted in offspring at 28 days of age and during the residual phase, 150 and/or 328 days of age. PBBs were detected in liver, kidney, and fat even 300 days following treatment termination confirming the remarkable biological stability and slow elimination of at least several PBB congeners. Retention of PBBs in tissues was correlated with hepatic histopathological alterations, renal and hepatic microsomal enzyme stimulation, and a reduction in duration of anesthesia produced by pentobarbital throughout the 10-month residual phase. These results suggest that metabolism of certain exogenous and endogenous lipophilic compounds may be modified for an extended time following perinatal exposure to PBBs.