[Experimental liver changes by means of polychlorinated biphenyls (PCB)]

Liver changes were studied after acut and subchronic exposition to mixtures of polychlorinated biphenyls (PCB) differing in their average chlorine content. Morphologically, the liver changes consisted mainly of cell hypertrophy and proliferation of the smooth endoplasmic reticulum (SER). After subchronic feeding the SER membranes formed membrane arrays. In addition to that the livers showed a hepatic porphyria. It was found that the porphyria was due to an inhibition of uroporphyrin decarboxylation similar to that caused by hexachlorobenzene. The porphyrinogenic effect was increased by feeding PCB containing more highly chlorinated components. Concomitant with the proliferation of the SER a high induction of membrane bound drug metabolizing enzymes could be observed. Duration and amount of induction increased with the chlorine content of the PCB. This could be correlated to the persistence to highly chlorinated components.