| Perturbations in the developing nervous system have been associated with perinatal exposures to polychlorinated biphenyls (PCBs). To determine which PCBs accumulate in brain following perinatal exposure, Sprague-Dawley rats were exposed by gavage to Aroclor 1242 (4 or 16 mg/kg/day) during days 10-16 of gestation. At weaning (day 21), analysis of pup brain (frontal cortex, hippocampus, and caudate putamen) by gas chromatography revealed ten peaks representing 10-14 congeners in PCB-exposed animals. Brain PCB concentrations were greatest in high-dose pups for all congeners except for 2,4,4;Time-mated Sprague-Dawley rats were exposed on days 10-16 of gestation to three environmentally-relevant PCBs: 2,4,4;Utilizing a tritium release assay, no inhibition of rat caudate putamen tyrosine hydroxylase activity by Aroclor 1242 was detected in vitro. While planaria (Dugesia dorotocephala) exposed to a known tyrosine hydroxylase inhibitor, 3-iodo-L-tyrosine, demonstrated both decreased head dopamine concentrations and eye pigmentation (presumably melanin), exposure of planaria to Aroclor 1242 resulted in only a decrease in head dopamine concentration. These data are consistent with other studies associating PCB exposure and decreased dopamine synthesis; however, inhibition of tyrosine hydroxylase was not observed. |
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