Dietary sodium induces a redistribution of the tubular metabolic workload
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Date
2017-11-15
DOI
Authors
Udwan, Khalil
Abed, Ahmed
Roth, Isabelle
Dizin, Eva
Maillard, Marc
Bettoni, Carla
Loffing, Johannes
Wagner, Carsten A.
Edwards, Aurelie
Feraille, Eric
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Published version
OA Version
Citation
Khalil Udwan, Ahmed Abed, Isabelle Roth, Eva Dizin, Marc Maillard, Carla Bettoni, Johannes Loffing, Carsten A Wagner, Aurelie Edwards, Eric Feraille. 2017. "Dietary sodium induces a redistribution of the tubular metabolic workload." JOURNAL OF PHYSIOLOGY, Volume 595, Issue 22, pp. 6905 - 6922 (18). https://doi.org/10.1113/JP274927
Abstract
Na+ excretion by the kidney varies according to dietary Na+ intake. We undertook a systematic study of the effects of dietary salt intake on glomerular filtration rate (GFR) and tubular Na+ reabsorption. We examined the renal adaptive response in mice subjected to 7 days of a low sodium diet (LSD) containing 0.01% Na+, a normal sodium diet (NSD) containing 0.18% Na+ and a moderately high sodium diet (HSD) containing 1.25% Na+. As expected, LSD did not alter measured GFR and increased the abundance of total and cell‐surface NHE3, NKCC2, NCC, α‐ENaC and cleaved γ‐ENaC compared to NSD. Mathematical modelling predicted that tubular Na+ reabsorption increased in the proximal tubule but decreased in the distal nephron because of diminished Na+ delivery. This prediction was confirmed by the natriuretic response to diuretics targeting the thick ascending limb, the distal convoluted tubule or the collecting system. On the other hand, HSD did not alter measured GFR but decreased the abundance of the aforementioned transporters compared to NSD. Mathematical modelling predicted that tubular Na+ reabsorption decreased in the proximal tubule but increased in distal segments with lower transport efficiency with respect to O2 consumption. This prediction was confirmed by the natriuretic response to diuretics. The activity of the metabolic sensor adenosine monophosphate‐activated protein kinase (AMPK) was related to the changes in tubular Na+ reabsorption. Our data show that fractional Na+ reabsorption is distributed differently according to dietary Na+ intake and induces changes in tubular O2 consumption and sodium transport efficiency.
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© 2017 The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.