TY - JOUR
T1 - Chronic metabolic acidosis reduces urinary oxalate excretion and promotes intestinal oxalate secretion in the rat
AU - Whittamore, Jonathan M.
AU - Hatch, Marguerite
N1 - Funding Information:
We are grateful to Anastasia Harris, Candi Morris, and Bonnie Murphy for their technical assistance during this study. This work was supported in part by a grant from the Oxalosis and Hyperoxaluria Foundation (OHF) to Dr. M. L. Green and National Institute of Diabetes and Digestive and Kidney Diseases Grant DK-56245 (M. Hatch) from the National Institutes of Health.
Publisher Copyright:
© 2015, Springer-Verlag Berlin Heidelberg.
PY - 2015/11/1
Y1 - 2015/11/1
N2 - 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2005], offering a more detailed analysis and interpretation of the data, together with new, previously unpublished observations revealing a marked impact on intestinal oxalate transport.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.
AB - 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.
KW - Acid–base
KW - Ammonium chloride
KW - Anion exchange
KW - Colon
KW - Kidney
KW - Ussing chamber
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U2 - 10.1007/s00240-015-0801-5
DO - 10.1007/s00240-015-0801-5
M3 - Article
C2 - 26162424
AN - SCOPUS:84946031531
SN - 2194-7228
VL - 43
SP - 489
EP - 499
JO - Urolithiasis
JF - Urolithiasis
IS - 6
ER -