BEHAVIORAL-EFFECTS OF PRENATAL AND POSTNATAL EXPOSURE TO INDIVIDUAL POLYCHLORINATED BIPHENYL CONGENERS IN RATS

Rats were exposed in utero and through mother's milk either to the coplanar PCB congener 3,3',4,4',5-CB (IUPAC no. 126) or to the mono-ortho-substituted PCB congener 2,3',4,4',5-CB (IUPAC no. 118). The different groups of mothers were exposed to 1 and 5 mg/kg body weight of PCB 118, and 2 mu g/kg b.w. of PCB 126 every second day from day 10 to day 20 of gestation. The exposure did not affect the body weight of the dams or the size, weight, sex ratio, or physical development of the offspring. Operant behavioral testing revealed that the PCB-exposed offspring showed both poorer visual discrimination and higher activity level than did the controls. The coplanar PCB 126 congener was the most potent treatment. These results show that both PCB 118 and PCB 126 produced significant neurotoxic effects in the offspring of exposed females in absence of clinical maternotoxic and fetotoxic effects.