Effects of KC-400 (polychlorinated biphenyls) on porphyrin metabolism--liver and blood porphyrin analyses in rats treated with KC-400.

Abstract

ABSTRACTTo investigate the influence of polychlorinated biphenyls (PCB) on porphyrin metabolism, Wistar rats were orally administered KC‐400. The mean value of liver/body weight ratio in normal rats was 3.86%, with a range of 3.44% to 5.22%. Their mean blood protoporphyrin level was 23.3 μg/dl packed cell volume (p.c.v.), with a range of 11.8 to 64.4 μg/dl p.c.v., and their mean liver protoporphyrin level was 0.17 μg/gm wet weight, with a range of 0.03 to 0.40 μg/gm wet weight.A feed containing KC‐400 (140–160 ppm) was given for 2 to 20 weeks to 20 rats. The mean value of liver/body weight ratio was 5.00%, with a range of 3.80% to 6.16%. The mean erythrocyte protoporphyrin level was 47.4 μg/dl p.c.v., with a range of 19.7 to 83.2 μg/dl p.c.v., and the mean liver protoporphyrin level was 0.36 μg/gm wet weight, with a range of 0.04 to 0.67 μg/gm wet weight. The liver coproporphyrin level showed abnormalities in 2 of 20 rats fed the feed containing KC‐400, with values of 0.71 and 9.89 μg/gm wet weight, respectively. After administration of KC‐400 feed for 43 weeks, the mean value of blood coproporphyrin level rose to 32.1 μg/dl p.c.v., with a range of 11.4 to 54.6 μg/dl p.c.v. The mean erythrocyte protoporphyrin level was 74.3 μg/dl p.c.v., with a range of 49.5 to 102.1 μg/dl p.c.v. The mean liver coproporphyrin level was elevated to 5.15 μg/gm wet weight, with a range of 0.45 to 9.48 μg/gm wet weight, and the mean liver protoporphyrin level was 0.65 μg/gm wet weight, with a range of 0.43 to 9.88 μg/gm wet weight. Thus, there was an increase in both liver porphyrin and coproporphyrin following KC‐400 feeding. Liver cells in the rats with abnormal porphyrin levels exhibited a red fluorescence. From these results, we can deduce that KC‐400 may induce abnormalities in porphyrin metabolism, when it is fed orally for a long period of time. These abnormalities in porphyrin metabolism are limited to the liver only.