Chronic metabolic acidosis reduces urinary oxalate excretion and promotes intestinal oxalate secretion in the rat

Jonathan M. Whittamore, Marguerite Hatch

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Urinary oxalate excretion is reduced in rats during a chronic metabolic acidosis, but how this is achieved is not clear. In this report, we re-examine our prior work on the effects of a metabolic acidosis on urinary oxalate handling [Green et al., Am J Physiol Ren Physiol 289(3):F536–F543, 2005], offering a more detailed analysis and interpretation of the data, together with new, previously unpublished observations revealing a marked impact on intestinal oxalate transport. Sprague–Dawley rats were provided with 0.28 M ammonium chloride in their drinking water for either 4 or 14 days followed by 24 h urine collections, blood-gas and serum ion analysis, and measurements of 14C-oxalate fluxes across isolated segments of the distal colon. Urinary oxalate excretion was significantly reduced by 75 % after just 4 days compared to control rats, and this was similarly sustained at 14 days. Oxalate:creatinine clearance ratios indicated enhanced net re-absorption of oxalate by the kidney during a metabolic acidosis, but this was not associated with any substantive changes to serum oxalate levels. In the distal colon, oxalate transport was dramatically altered from net absorption in controls (6.20 ± 0.63 pmol cm−2 h−1), to net secretion in rats with a metabolic acidosis (−5.19 ± 1.18 and −2.07 ± 1.05 pmol cm−2 h−1 at 4 and 14 days, respectively). Although we cannot rule out modifications to bi-directional oxalate movements along the proximal tubule, these findings support a gut-kidney axis in the management of oxalate homeostasis, where this shift in renal handling during a metabolic acidosis is associated with compensatory adaptations by the intestine.

Original languageEnglish (US)
Pages (from-to)489-499
Number of pages11
JournalUrolithiasis
Volume43
Issue number6
DOIs
StatePublished - Nov 1 2015
Externally publishedYes

Keywords

  • Acid–base
  • Ammonium chloride
  • Anion exchange
  • Colon
  • Kidney
  • Ussing chamber

ASJC Scopus subject areas

  • Urology

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