The technique of ex vivo 31P NMR spectroscopy has been used for the investigation of metabolic turnover in 15 cadaveric human kidneys obtained from brain-dead donors for transplantation. Measurements were carried out at 1.5 T time-dependently during regular hypothermic storage in histidine-tryptophan-α-ketoglutarate solution. The minimum delay between explantation and spectroscopy was 2 h 41 min. In one case of a discarded organ the measurements could be extended over a period of 161 h 35 min. A detailed kinetic model describing monoexponential ischemic phosphate turnover, which accounts for various interrelations of the NMR visible metabolites, has been derived. Averaged velocity constants of the decays of nucleotides and phosphomono- and -diesters ranged from 0.0047 to 0.294 h-1 at approximately 4° C. Intracellular pH decreased monoexponentially with an averaged velocity constant of 0.31 h-1.
Effects of vitamin E, C phosphate on intracellular pH and energy metabolism of the ischemic brain studied by 31P NMR spectroscopy