Effects of chlorocyclizine on pulmonary lipid metabolism in rats

Pulmonary lipidosis was induced in rats by including 0.36 and 0.54% chlorocyclizine in their diet. Chemical analyses of the lung tissue revealed a very marked increase in phosphatidylcholine concentration. Phosphatidylglycerol and phosphatidylinositol concentrations were also markedly increased. An increase in the phosphatidylcholine content was also observed in lavage fluid and macrophages. Microscopic examination of the cell fraction showed that almost all the cells of the lavage fluid were macrophages and that histochemically demonstrable acid esterase activity was mostly inversely related to storage of lipids in the cells. Sonication of macrophages isolated from normal or chlorocyclizine-treated rats yielded a soluble acid phospholipase (pH optimum, 4.0) and a neutral (pH optimum, 8.2) membrane-bound, CaCl₂-dependent enzyme. An inhibitory effect of chlorocyclizine in vitro on the activity of the soluble phospholipase was shown.