Jørgen Frøkiær

Long-term aldosterone treatment induces decreased apical but increased basolateral expression of AQP2 in CCD of rat kidney

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

  • Sophie de Seigneux, Denmark
  • Jakob Nielsen, Denmark
  • Emma T B Olesen
  • Henrik Dimke, Denmark
  • Tae-Hwan Kwon
  • ,
  • Jørgen Frøkiaer
  • Søren Nielsen, Denmark
  • Henrik Anthony Dimke, Denmark
The purpose of the present studies was to determine the effects of high-dose aldosterone and dDAVP treatment on renal aquaporin-2 (AQP2) regulation and urinary concentration. Rats were treated for 6 days with either vehicle (CON; n = 8), dDAVP (0.5 ng/h, dDAVP, n = 10), aldosterone (Aldo, 150 microg/day, n = 10) or combined dDAVP and aldosterone treatment (dDAVP+Aldo, n = 10) and had free access to water with a fixed food intake. Aldosterone treatment induced hypokalemia, decreased urine osmolality, and increased the urine volume and water intake in ALDO compared with CON and dDAVP+Aldo compared with dDAVP. Immunohistochemistry and semiquantitative laser confocal microscopy revealed a distinct increase in basolateral domain AQP2 labeling in cortical collecting duct (CCD) principal cells and a reduction in apical domain labeling in Aldo compared with CON rats. Given the presence of hypokalemia in aldosterone-treated rats, we studied dietary-induced hypokalemia in rats, which also reduced apical AQP2 expression in the CCD but did not induce any increase in basolateral AQP2 expression in the CCD as observed with aldosterone treatment. The aldosterone-induced basolateral AQP2 expression in the CCD was thus independent of hypokalemia but was dependent on the presence of sodium and aldosterone. This redistribution was clearly blocked by mineralocorticoid receptor blockade. The increased basolateral expression of AQP2 induced by aldosterone may play a significant role in water metabolism in conditions with increased sodium reabsorption in the CCD.
Original languageEnglish
JournalAmerican Journal of Physiology: Renal Physiology
Pages (from-to)F87-99
Publication statusPublished - 2007

    Research areas

  • Aldosterone, Angiotensin II, Animals, Aquaporin 2, Deamino Arginine Vasopressin, Drinking, Eating, Homeostasis, Hypokalemia, Immunoblotting, Immunohistochemistry, Kidney Cortex, Kidney Tubules, Collecting, Male, Microscopy, Immunoelectron, Phosphorylation, Potassium Deficiency, Rats, Rats, Sprague-Dawley, Rats, Wistar, Renal Agents, Serine, Subcellular Fractions, Water

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