AJP - Endocrinology and Metabolism, Vol 248, Issue 5 553-E559, Copyright © 1985 by American Physiological Society
Incorporation of glucose carbons into rat lung lipids after exposure to 0.6 ppm ozone
D. J. Bassett and J. L. Rabinowitz
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.
