Ultrastructural changes in rat Clara cells induced by bis(4-amino-3-methylcyclohexyl)methane.

Repeated oral administration of bis(4-amino-3-methylcyclohexyl)methane to rats induced unusual ultrastructural changes in Clara cells of the bronchiolar epithelium, involving marked accumulation of electron-dense inclusion bodies with a lamellar structure in the cytoplasm. The appearance of the inclusion bodies was speculated to result from accumulation of complexes formed between the agent and phospholipids within lysosomes, a condition known as drug-induced lipidosis. This finding appeared noteworthy, since it might reflect high potential for metabolism of xenobiotic compounds in Clara cells.