Incorporation of glucose carbons into rat lung lipids after exposure to 0.6 ppm ozone.

Continuous exposure to low concentrations of ozone has previously been associated with proliferation of lung alveolar type II epithelial cells. In this study, 14C incorporation into tissue lipids was determined in isolated rat lungs by perfusion with [U-14C]glucose, at a time of maximal hyperplasia brought about by 3 days continuous exposure to 0.6 ppm ozone. Ozone exposed lungs exhibited increased rates of glycolytic energy production, indicated by an 89% increase in 3H2O generation on perfusion with [5-3H]glucose, from a control value of 17.5 +/- 2.1 mumol X h-1 X g-1 X dry wt-1 (+/- SE, n = 4). Ozone exposure resulted in enhanced 14C incorporations into glyceride-glycerol and fatty acid moieties of lung lipids of 95 and 180%, respectively, with a greater proportion of label being recovered in shorter chain fatty acids. Although increased labeling was observed in both neutral and phospholipids, the pattern of 14C recovery suggested a relative increased glucose carbon incorporation into lung free fatty acids, phosphatidic acid, and such membrane associated lipids as phosphatidylinositol and those containing sphingosine. These results are consistent with the needs of a dividing cell population for enhanced energy production and synthesis of new lipids.