Remnant kidney metabolism in the dog

A marked increase in oxygen uptake (Qo2) per nephron has been described in the remnant kidney of the rat. However, it is not known which substrates support renal metabolism in remnant kidney nor is it known whether similar changes in Qo2 occur in other species. Remnant kidney in the dog was induced by ligation of 60 to 75% of the renal arterial branches on one side followed 1 to 2 wk later by contralateral nephrectomy. At 3 months marked hypertrophy of the remnant kidney was found and the glomerular filtration rate was 18 +/- 1.8 mL/min compared with 31 +/- 2 in a normal kidney (P less than 0.01). Qo2 was 689 +/- 60 mumol/min/100 mL glomerular filtration rate in the remnant kidney compared with 564 +/- 42 mumol/min/100 mL glomerular filtration rate in the normal kidney (P less than 0.01). Total renal ammoniagenesis per nephron increased to values found in chronic metabolic acidosis although serum (K+) and (HCO3-) were no different than in the normal dog. The oxidation of glutamine and lactate by remnant kidneys accounted for over 80% of Qo2, similar to that of normal kidneys. It is concluded that hypermetabolism per nephron occurs in the remnant kidney of the dog and that glutamine and lactate are the major energy substrates in remnant kidney. Furthermore, factors other than serum (K+) and (HCO3-) augment ammoniagenesis in this model. However, when these results are expressed per whole kidney or per gram of tissue, hypermetabolism does not occur in these remnant kidneys.(ABSTRACT TRUNCATED AT 250 WORDS)