The Effects of Polychlorinated Biphenyl (PCB) on the Functions of Human Erythrocyte Membranes

The effects of polychlorinated biphenyl (Kanechlor-400) on the functions of human erythrocyte membranes were studied, and the following results were obtained. (1) Kanechlor-400 (KC-400) inhibited Ca2+-ATPase activity (maximal inhibition : 72%), while non-chlorinated biphenyl failed to inhibit Ca2+-ATPase activity. The inhibition of Ca2+-ATPase activity by KC-400 was due to a change in maximal rate (Vmax), but not to a change in affinity (Km) for Ca2+ or ATP. (2) KC-400 and biphenyl protected erythrocytes against hypotonic hemolysis, but KC-400 was a more potent stabilizer of the membrane (by at least one order of magnitude) than biphenyl. (3) KC-400 and biphenyl caused similar shape alterations in erythrocytes. Namely, these compounds induced shape changes from normal discocytes to invaginated cells and finally to spherocytes. However, the concentrations required to produce shape alterations are one order of magnitude lower for KC-400 than for biphenyl. (4) These data suggested that KC-400 penetrates into the interior of the membrane, and perturbs its structure and function. Chlorination of the aromatic rings increases not only the inhibitory action on Ca2+-ATPase activity, but also the anti-hemolytic and shape changing actions.