Low Na, high K diet and the role of aldosterone in BK-mediated K excretion

Ryan J. Cornelius, Donghai Wen, Huaqing Li, Yang Yuan, Jun Wang-France, Paige C. Warner, Steven C. Sansom

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

A low Na, high K diet (LNaHK) is associated with a low rate of cardiovascular (CV) disease in many societies. Part of the benefit of LNaHK relies on its diuretic effects; however, the role of aldosterone (aldo) in the diuresis is not understood. LNaHK mice exhibit an increase in renal K secretion that is dependent on the large, Ca-activated K channel, (BK-α with accessory BK-β4; BK-α/β4). We hypothesized that aldo causes an osmotic diuresis by increasing BK-α/β4-mediated K secretion in LNaHK mice. We found that the plasma aldo concentration (P[aldo]) was elevated by 10-fold in LNaHK mice compared with control diet (Con) mice. We subjected LNaHK mice to either sham surgery (sham), adrenalectomy (ADX) with low aldo replacement (ADX-LA), or ADX with high aldo replacement (ADX-HA). Compared to sham, the urinary flow, K excretion rate, transtubular K gradient (TTKG), and BK-α and BK-β4 expressions, were decreased in ADX-LA, but not different in ADX-HA. BK-β4 knockout (β4KO) and WT mice exhibited similar K clearance and TTKG in the ADX-LA groups; however, in sham and ADX-HA, the K clearance and TTKG of β4KO were less than WT. In response to amiloride treatment, the osmolar clearance was increased in WT Con, decreased in WT LNaHK, and unchanged in β4KO LNaHK. These data show that the high P[aldo] of LNaHK mice is necessary to generate a high rate of BK-α/β4-mediated K secretion, which creates an osmotic diuresis that may contribute to a reduction in CV disease.

Original languageEnglish (US)
Article numbere0115515
JournalPloS one
Volume10
Issue number1
DOIs
StatePublished - Jan 21 2015

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

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    Cornelius, R. J., Wen, D., Li, H., Yuan, Y., Wang-France, J., Warner, P. C., & Sansom, S. C. (2015). Low Na, high K diet and the role of aldosterone in BK-mediated K excretion. PloS one, 10(1), [e0115515]. https://doi.org/10.1371/journal.pone.0115515