Validation of a toxicity testing model by evaluating oxygen supply and energy state in the isolated perfused rat kidney

Validation of a toxicity testing model concerning energy metabolism was attempted by evaluating the oxygen supply and energy state in an isolated perfused rat kidney of single-pass preparation without albumin. Perfusion was performed at a temperature of 31°C, flow rate of 11.0 mL/g/min, and pressure of 81–104 mmHg. The perfusate was saturated with 95% O₂/5% CO₂. After preperfusion for 30 min, the redox states of cytochrome aa₃ and c and pyridine nucleotides (PN) in the perfused kidney were measured to be stable for 90 min by a scanning reflectance spectrophotometry and surface fluorometry, respectively. During the same period, the contents of ATP and inorganic phosphate (Pi) in the perfused kidney were also measured to be stable by ³¹P-NMR spectroscopy. The oxygen supply to the cell was more than the amount required for the basal metabolism of the cell. For assessment of the effects of chemical agents on the renal cell metabolism, this preparation of the perfused rat kidney was considered to have several advantages, despite some of its inherent limitations in the function of the kidney.