Polychlorinated Biphenyl-Induced Alteration of Biologic Parameters

Polychlorinated Biphenyl-Induced Alteration of Biologic Parameters in the Rat. BRUCKNER, J. V., KHANNA, K. L. AND CORNISH, H. H. (1974). Toxicol. Appl. Phurmacol. 2-8, 189-199, Aroclor 1242, a commercial polychlorinated biphenyl (PCB) mixture, was administered ip to rats for 10 weeks. Principal findings included: loss of body weight; hepatic and renal damage, with some animals exhibiting renal papillary epithelial hyperplasia; slight reduction in erythrocyte count, diameter, and hemoglobin content, with an elevation in serum iron; diminished plasma corticosteroid and glucose concentrations; increased urinary excretion of protein, sugars, and coproporphyrin. The effect of PCBs on several hepatic microsomal enzymatic parameters was also evaluated. Maximal hydroxylation and N-demethylation activities were observed 3-10 days following a single ip injection (100 mg/kg). Each remained significantly higher than control values after 20 days, with hydroxylation activity still 150 o/0 of controls after 40 days. The minimal effective single dose for induction of hydroxylation activity was approximately 5 mg/kg. Induction of hydroxylation activity was found to be dose-dependent; however, a smaller degree of correlation was noted between N-demethylation activity and dose. Values for cytochromes PbsO and b5 and NADPH-cytochrome c reductase activity were observed to roughly parallel hydroxylation and N-demethylation activities, the highest degree of correlation was manifest between enzymatic activity and cytochrome Pb5” values.