Glucose metabolism by isolated rat lung cells

Abstract

Dispersed cells were prepared from rat lungs incubated with collagenase after prior perfusion to remove blood. By light and electron microscopy, the preparation was heterogenous comprising the cell types generally found in intact lung. Glucose consumption at 37 C was 189 ± 22 (SE) nmoles/hr per 107 cells and was linear over a 2 hr period. Lactate and pyruvate production accounted for 59% of glucose utilized, but glucose was also oxidized to CO2 and incorporated into lipids and glycoproteins. The pentose shunt pathway accounted for 2.2 ± 0.7% of the glucose metabolized. Hydrogen transport mechanisms between cytosolic and mitochondrial spaces were studied with metabolic inhibitors and found to be of low activity. Respiration was depressed 20% from endogenous rates in the presence of 5 mM glucose (Crabtree effect). The Crabtree effect was associated with increased net fatty acid synthesis from acetate. Anoxia during incubation resulted in a fivefold rise in lactate pyruvate ratio, a marked drop in the phosphate potential, and decreased incorporation of acetate into lipids. Enzymatically prepared lung cells provide a metabolically active material for study of lung metabolism and for further fractionation into homogeneous cell populations.