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Dietary sodium induces a redistribution of the tubular metabolic workload


Udwan, Khalil; Abed, Ahmed; Roth, Isabelle; Dizin, Eva; Maillard, Marc; Bettoni, Carla; Loffing, Johannes; Wagner, Carsten A; Edwards, Aurélie; Feraille, Eric (2017). Dietary sodium induces a redistribution of the tubular metabolic workload. Journal of Physiology:Epub ahead of print.

Abstract

Na+ excretion by the kidney varies according to dietary Na+ intake. We undertook a systematic study on 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+ , as well as 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 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. This article is protected by copyright. All rights reserved.

Abstract

Na+ excretion by the kidney varies according to dietary Na+ intake. We undertook a systematic study on 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+ , as well as 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 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. This article is protected by copyright. All rights reserved.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > Institute of Anatomy
Dewey Decimal Classification:570 Life sciences; biology
610 Medicine & health
Language:English
Date:20 September 2017
Deposited On:10 Oct 2017 14:05
Last Modified:10 Oct 2017 14:05
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:0022-3751
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1113/JP274927
PubMed ID:28940314

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Language: English
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Embargo till: 2018-09-20