Ultrastructural and biochemical study of the action of benzoctamine and maprotiline on the rat liver

The changes induced in the liver epithelium of male rats by two dibenzobicyclo octadiene analogues, maprotiline and benzoctamine, were compared. Maprotiline at high dose levels produced induction of microsomal membranes and of constituent enzymes of the endoplasmic reticulum (ER), preceded by the appearance of altered peribiliary structures, part of which showed the morphological aspect of myeloid bodies. These particles, which appeared to develop at the expense of peribiliary dense bodies, were considered to be of a lysosomal nature by virtue of their acid phosphatase activity. All the hepatic changes induced by maprotiline proved to be reversible upon cessation of treatment. Since changes similar to those caused by maprotiline were also induced by amitriptyline, imipramine and chlorpromazine, they may conceivably be produced nonspecifically by lipophilic bases. Benzoctamine, being of a less basic nature, was found to induce reversible hypertrophy of the SER only.