FREEZE-FRACTURE STUDIES OF CYTOPLASMIC INCLUSIONS OCCURRING IN EXPERIMENTAL LIPIDOSIS AS INDUCED BY AMPHIPHILIC CATIONIC DRUGS

The ultrastructure of cytoplasmic inclusions, which characterizes experimental lipidosis as induced by several amphiphilic cationic drugs, was studied by freeze-fracturing and thin-sectioning. Retinal and adrenal tissues of rats chronically treated with high oral doses of chlorphentermine were used. In thin sections the cytoplasmic inclusions, which were previously shown to represent lysosomes overloaded with polar lipids, exhibit lamellated or lattice-like internal patterns. The present freeze-fracture observations apparently indicate that the lamellated inclusions contain polar lipids in the lamellar phase, whereas those with lattice-like patterns contain polar lipids in a hexagonal phase.