In an attempt to study the effect of polychlorinated biphenyls on iodine metabolism, Kanechlor KC-400 (a mixture of PCB) was administered to rats.
At 3, 10, 20 and 30 days after a single oral administration of KC-400, the following studies were performed; 1) weighing of liver and thyroid, 2) Kinetics of whole-body ¹³¹I-thyroxine, 3) biliary excretion of ¹³¹I-thyroxine, 4) analysis of the radioactive components in the bile.
A single administration of 200mg dose of KC-400 drastically affected the iodine metabolism of rats as follows; the weights of liver and thyroid were increased at least for 30 days, elimination of thyroxine from the whole body was accelerated, the biliary excretion of thyroxine was enhanced at least for 20 days, and throxine gluculonide in bile increased for two hours after injection of ¹³¹I-thyroxine.