AJP - Endocrinology and Metabolism, Vol 246, Issue 5 426-E429, Copyright © 1984 by American Physiological Society
Lactate and regulation of lung glycolytic rate
A. B. Fisher and C. Dodia
The effect of exogenous lactate on glycolytic rate was studied with the
isolated perfused rat lung. Glucose utilization was estimated from the rate
of 3H2O production from [5-3H]glucose, and lactate and pyruvate production
was measured by perfusate assay. Glucose utilization was unaffected by
addition of 0.5 mM lactate to the perfusate but decreased by 27% with 1 mM
lactate. With 2 mM lactate, glucose utilization was decreased by 46% and
lactate production decreased 95%. With addition of 0.2 mM pyruvate plus 2
mM lactate, glucose utilization was decreased 63% compared with control.
These data indicate that the effect of lactate on glucose utilization was
not through change in the cellular redox state. During lung anoxia produced
by ventilation with CO, glucose utilization and lactate production were
again markedly decreased by addition of lactate (2 mM) to the perfusate.
However, addition of pyruvate plus lactate resulted in a markedly
stimulated rate of glucose utilization. This result indicates that during
anoxia the effect of lactate on glycolysis resulted from alteration of the
redox ratio. This study indicates that lactate influences the rate of
glycolysis in the normal lung through its utilization as a substrate for
mitochondrial metabolism. During anoxia, changes in the lung redox state
with lactate are a major determinant of the glycolytic rate.
