ASSESSMENT OF DYNAMIC INTRACELLULAR PH BY (31)PHOSPHOR NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY ((31)PNMRS) ON ISCHEMIC DOG KIDNEYS AFTER PERFUSION WITH HTK-SOLUTION

Prolongation of renal ischemic tolerance by preservation with the hist idine-tryptophanketoglutarate (HTK)-solution enables organ preserving renal surgery and transplantation which is in clinical use at various medical institutions. The main principle of the HTK-solution consists in its high buffering capacitiy, which is due to an amino-acid buffer concentration of 180/18 mmol/l histidine/histidine-hydrochloride. As o ur main interest was to determine whether perfusion and thus buffering of the extracellular compartment of the kidney influences the acidifi cation of the intracellular compartment, changes of extracellular pH ( pH(ez)) and intracellular pH (pH(iz)) were investigated at different t emperatures after perfu sion with HTK-solution resp. non-buffering Rin ger-solution. Measurement of pH(ez) was implemented by ion-sensitive e lectrodes, whereas pH(iz) was determined by (31)PNMRS. In contrast to a perfusion with Ringer-solution, perfusion with HTK-solution prevents a considerable decrease of the ischemic acidification of both cellula r compartments at 37 degrees C and 20 degrees C. After perfusion with HTK-solution and an incubation temperature of 5 degrees C pH(iz) decre ases slightly. pH(ez) remains constant during 150 min of ischemia.