31P NMR spectroscopy of isolated perfused lungs

31P NMR spectra of isolated blood-perfused pig lungs were obtained by degassing the lungs in vivo to remove field inhomogeneities caused by air-tissue interfaces. The spectra show the presence of ATP, phosphodiester, inorganic phosphate, and phosphomonoester, but no phosphocreatine. All the metabolites remained stable for more than 4 h when the lungs were perfused with oxygenated blood. Blood gas tensions, glucose concentration, pH, and temperature were controlled throughout the experiment. During anoxia or ischemia, ATP and intracellular pH declined and Pi increased but returned to control levels during subsequent normoxia or reperfusion. These results demonstrate the applicability of NMR spectroscopy to isolated perfused lungs, enabling studies of metabolic processes in normal and pathologic lungs, as well as establishment of optimal conditions for lung preservation for transplantation.