Influence of indomethacin on cation excretion after acute unilateral nephrectomy in dogs

Acute unilateral nephrectomy (AUN) causes functional changes in the remaining kidney. Since renal prostaglandins (PGs) may participate in this response, we investigated the effect of the PG synthetase inhibitor, indomethacin (INDO), on the function of the remaining kidney after AUN. Glomerular filtration rate (GFR), effective renal plasma flow (ERPF), filtration fraction (FF), sodium excretion, and potassium excretion were measured for 1 hr prior to and 3 hr after AUN in dogs anesthetized with sodium pentobarbital. Group I and II animals underwent AUN. A third group was sham-operated (Group III). Group I received INDO (2 mg/kg) before and 2 hr after AUN, while Groups II and III received a buffered saline vehicle. AUN alone (Group II) had no effect on GFR, ERPF, FF, or sodium excretion, while potassium excretion was increased. In animals administered INDO prior to AUN (Group I), the increase in potassium excretion was abolished, FF rose and sodium excretion, while potassium excretion was increased. In animals administered INDO prior to AUN (Group I), the increase in potassium excretion was abolished, FF rose and sodifore and 2 hr after AUN, while Groups II and III received a buffered saline vehicle. AUN alone (Group II) had no effect on GFR, ERPF, FF, or sodium excretion, while potassium excretion was increased. In animals administered INDO prior to AUN (Group I), the increase in potassium excretion was abolished, FF rose and sodium excretion was decreased. Results suggest that renal PGs participate in the compensatory response of the remaining kidney to AUN and may specifically play a role in increased cation excretion following AUN.