Effects of Polychlorinated Biphenyls on Reproductive Performance

Toxicity of Polychlorinated biphenyls (PCB) were studied in matured female minks and mice with special reference to the reproductive activity. The results obtained were as follows. 1) Complete reproductive failure occured in the minks exposed to PCB more than 1.50 mg/kg/day, and significantly reduced number of kits were seen in the group of 0.30 mg/kg/day of PCB when the exposure was continued from 6 months prior to mate untill the end of gestation period. On the contrary no effect was seen on the reproductive performance of mice exposed to 20 mg/kg/day of PCB. 2) Unrestrained implantation was observed even in the female minks treated with 2.25 mg/kg/day of PCB. 3) The average body weight at birth of the mink kits from females exposed to PCB at the level of 0.30 mg/kg/day was significantly smaller than that of kits from the control group, and the survival ratio of mink kits in the group of 0.15 mg/kg/day was significantly less than that of kits in the control group. On the other hand both of the body weight and survival ratio of mouse kits from females exposed to even at the level as high as 20 mg/kg/day were not significantly different from those of kits in the control group. 4) Even though exposing to PCB was limited in the period of gestation, the reduced reproducibility was seen as same as mentioned above. 5) The littler size in the female minks which were exposed to 0.75 mg/kg/day of PCB for a period of 9 months and retained on the same condition with the control group for the following 10 months, and survival ratio of the kits from them were not significantly different from those in the control group. 6) A considerably large amount of PCB was detected in the dead fetuses from the female minks exposed to PCB, also a severe liver damage being found in them. 7) Teratism was not observed in the kits from the PCB exposed female minks and mice. 8) A single-dose ip LD50 of PCB for adult female mink was about 1/2 of that for mouse. 9) Exposing to 0.75mg/kg/day of PCB did affect on the body weight gain of adult female minks, though exposing to 20 mg/kg/day of PCB didn't affect on that of adult female mice at all. 10) The most noteworthy lesion in adult female minks exposed to PCB was histopathologically seen in liver.