US EPA

2192844 

Journal Article 

Abstract 

Developmental exposure to the 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153): thyroid hormones and neurobehavioral effects 

Taylor, MM; Hedge, JM; Jarema, KA; Crofton, KM 

2000 

1 

Toxicologist
ISSN: 0731-9193 

54 

1 

173 

English 

Polychlorinated biphenyls (PCBs) are pervasive environmental contaminants that have been shown to detrimentally affect somatic and behavioral endpoints. Primiparous Long-Evans rats were exposed to 0, 1, 5, 20 or 60 mg/kg/day PCB 153 via oral gavage from Gestation Day 6 through Postnatal Day 21. Offspring were evaluated at various ages for circulating thyroid hormone concentrations (total serum triiodothyronine (T3) and thyroxine (T4)), survival, body weight, eye opening, motor activity development, auditory startle response and auditory thresholds. A dose-dependent moderate reduction in T4 concentrations was apparent from PND4 to PND21, with a maximal effect at 60 mg/kg (52% decrease at PND21). T4 in dams on PND22 was decreased up to 32% at 60 mg/kg. Concentrations of T3 did not differ from controls for pups or dams. There was no body weight gain reduction in either the dams or the offspring. There was no alteration in eye opening or survival. There was an age- but not dose-dependent increase in motor activity from PND7 to 14. Further, auditory startle amplitudes were not affected on PND24. These data suggest that PCB 153 is much less potent as a thyroid hormone disruptor during development compared to Aroclor 1254. Furthermore, PCB 153 at the doses tested does not seem to alter many of the endpoints previously shown to be sensitive to Aroclor 1254 exposure.