Regulation of the Renal NaCl Cotransporter and Its Role in Potassium Homeostasis

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  • Ewout J Hoorn, Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark.
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  • Martin Gritter, Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark.
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  • Catherina A Cuevas, Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands; and Department of Biomedicine, Aarhus University, Aarhus, Denmark.
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  • Robert A Fenton

Daily dietary potassium (K+) intake may be as large as the extracellular K+ pool. To avoid acute hyperkalemia, rapid removal of K+ from the extracellular space is essential. This is achieved by translocating K+ into cells and increasing urinary K+ excretion. Emerging data now indicate that the renal thiazide-sensitive NaCl cotransporter (NCC) is critically involved in this homeostatic kaliuretic response. This suggests that the early distal convoluted tubule (DCT) is a K+ sensor that can modify sodium (Na+) delivery to downstream segments to promote or limit K+ secretion. K+ sensing is mediated by the basolateral K+ channels Kir4.1/5.1, a capacity that the DCT likely shares with other nephron segments. Thus, next to K+-induced aldosterone secretion, K+ sensing by renal epithelial cells represents a second feedback mechanism to control K+ balance. NCC's role in K+ homeostasis has both physiological and pathophysiological implications. During hypovolemia, NCC activation by the renin-angiotensin system stimulates Na+ reabsorption while preventing K+ secretion. Conversely, NCC inactivation by high dietary K+ intake maximizes kaliuresis and limits Na+ retention, despite high aldosterone levels. NCC activation by a low-K+ diet contributes to salt-sensitive hypertension. K+-induced natriuresis through NCC offers a novel explanation for the antihypertensive effects of a high-K+ diet. A possible role for K+ in chronic kidney disease is also emerging, as epidemiological data reveal associations between higher urinary K+ excretion and improved renal outcomes. This comprehensive review will embed these novel insights on NCC regulation into existing concepts of K+ homeostasis in health and disease.

Original languageEnglish
JournalPhysiological Reviews
Volume100
Issue1
Pages (from-to)321-356
Number of pages36
ISSN0031-9333
DOIs
Publication statusPublished - 1 Jan 2020

    Research areas

  • CORTICAL COLLECTING DUCT, DISTAL CONVOLUTED TUBULE, FAMILIAL HYPERKALEMIC HYPERTENSION, KELCH-LIKE 3, NA+-CL-COTRANSPORTER, PSEUDOHYPOALDOSTERONISM TYPE-II, SODIUM-CHLORIDE COTRANSPORTER, TAMM-HORSFALL PROTEIN, THICK ASCENDING LIMB, URINARY EXTRACELLULAR VESICLES, WNK kinases, aldosterone, chronic kidney disease, distal convoluted tubule, hypertension

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