Metabolism of hyperpolarized [1‐ 13 C]pyruvate in the isolated perfused rat lung – an ischemia study

We report studies of the effect of ischemia on the metabolic activity of the intact perfused lung and its restoration after a period of reperfusion. Two groups of rat lungs were studied using hyperpolarized 1‐ 13 C pyruvate to compare the rate of lactate labeling differing only in the temporal ordering of ischemic and normoxic acquisitions. In both cases, a several‐fold increase in lactate labeling was observed immediately after a 25‐min ischemia event as was its reversal back to the baseline after 30–40 min of resumed perfusion ( n  = 5, p  < 0.025 for both comparisons). These results were corroborated by 31 P spectroscopy and correspond well to measured changes in lactate pool size determined by 1 H spectroscopy of freeze‐clamped specimens. Copyright © 2012 John Wiley & Sons, Ltd.