High respiratory quotient of dog kidney in vivo

The R.Q. of the dog kidney was determined in vivo in unilaterally nephrectomized dogs during the infusion of a) NaCl, b) α-keto acids, c) during acute lactate alkalosis and d) during acute acidosis (HCl or H2SO4). The mean (± S.E.) R.Q.'s observed and their statistical significance above unity respectively were a) 1.33 ± 0.07, P < 0.05 ( n = 17); b) 1.27 ± 0.08, P < 0.05 ( n = 19); c) 1.18 ± 0.08, 0.05 < P < 0.10 ( n = 34); and d) 1.14 ± 0.11, P > 0.10 ( n = 32). The excess in renal CO2 production over O2 consumption is interpreted to indicate that a portion of the kidney utilizes substrates by coupled anaerobic oxidation-reductions yielding CO2. The two experimental conditions in which maximal (NaCl infusion) and minimal (acidosis) medullary counter-current multiplier activity should occur were also those with the highest and lowest mean renal CO2 production rates. None of the experimental groups showed any significant changes in O2 consumption. A relationship between renal anaerobic metabolism as manifested by excess CO2 production and renal excretory function is postulated.