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Cited by 223Ion Transport and Channel RegulationElectrolyte and hormonal disordersAcute Kidney Injury Research

The Physiology of Urinary Concentration: An Update

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Sands, Jeff M., Layton, Harold E.·2009·Seminars in Nephrology
DOI 10.1016/j.semnephrol.2009.03.008PMC PMC2709207
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Abstract

The renal medulla produces concentrated urine through the generation of an osmotic gradient extending from the cortico-medullary boundary to the inner medullary tip. This gradient is generated in the outer medulla by the countercurrent multiplication of a comparatively small transepithelial difference in osmotic pressure. This small difference, called a single effect, arises from active NaCl reabsorption from thick ascending limbs, which dilutes ascending limb flow relative to flow in vessels and other tubules. In the inner medulla, the gradient may also be generated by the countercurrent multiplication of a single effect, but the single effect has not been definitively identified. There have been important recent advances in our understanding of key components of the urine concentrating mechanism. In particular, the identification and localization of key transport proteins for water, urea, and sodium, the elucidation of the role and regulation of osmoprotective osmolytes, better resolution of the anatomical relationships in the medulla, and improvements in mathematic modeling of the urine concentrating mechanism. Continued experimental investigation of transepithelial transport and its regulation, both in normal animals and in knock-out mice, and incorporation of the resulting information into mathematic simulations, may help to more fully elucidate the inner medullary urine concentrating mechanism.

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  • In kidneys, an osmotic gradient from the cortico-medullary boundary to the inner medullary tip is maintained to allow water reabsorption and urine concentration (countercurrent multiplication).

    “In the kidneys, an osmotic gradient arising from the cortico-medullary boundary to the inner medullary tip is normally maintained as a mechanism that allows reabsorption of water and concentration of the urine, a process also called countercurrent multiplication143.”

    From Gut microbiota and cardiovascular disease. (2020) · cites this paper as [143]

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  1. [40]Niesel W Röskenbleck H Konzentrierung von Lösungen unterschiedlicher Zusammensetzung durch alleinige Gegenstromdiffusion und Geggenstromosmose als möglicher Mechanismus der Harnkonzentrierung Pfluegers Arch 1965 283 230 241 14311307

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Authors
Sands, J. M., & Layton, H. E.
Affiliations
  • Emory University (US)
  • Duke University (US)
ORCID
Sands, Jeff M.
Venue
Seminars in Nephrology
Publisher
Elsevier BV
Published
2009-05
Volume
29
Issue
3
Pages
178-195
ISSN
0270-9295 (ISSN-L)
DOI
10.1016/j.semnephrol.2009.03.008
PMC
PMC2709207
OpenAlex
W2063549176
Cited by
223
References
127
Citations by year
2026: 13 · 2025: 13 · 2024: 21 · 2023: 12 · 2022: 15 · 2021: 8 · 2020: 16 · 2019: 17 · 2018: 16 · 2017: 16 · 2016: 15 · 2015: 11 · 2014: 13 · 2013: 12 · 2012: 15
FWCI
0.64
Type
journal article
Language
en
Open access
Licence
www.elsevier.com/tdm/userlicense/1.0/ (tdm)
Locations
  • Seminars in Nephrology (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • National Institutes of Health (UL1TR000454)
  • National Institute of Diabetes and Digestive and Kidney Diseases (P01 DK-61521, R01-DK41707, R01DK042091, P01DK061521, R01-DK42091, R01DK041707)
  • National Center for Research Resources (UL1RR025008)
  • National Center for Advancing Translational Sciences
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Ion Transport and Channel Regulation
  • Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Electrolyte and hormonal disorders
  • Health Sciences › Medicine › Nephrology › Acute Kidney Injury Research
Keywords
urine concentration, countercurrent multiplication, renal medulla, osmotic gradient, thick ascending limb, NaCl reabsorption, inner medulla, urea transport, water transport, transepithelial transport, knockout mice
MeSH terms
Animals, Body Water, Kidney Concentrating Ability, Kidney Medulla, Kidney Tubules, Collecting, Models, Biological, Models, Theoretical, Sodium Chloride, Urea, Vasopressins, Mice, Knockout, Aquaporins, Membrane Transport Proteins, Mice

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