Potassium inhibits free radical formation

Richard D. McCabe, Michael A. Bakarich, Kumud Srivastava, David B. Young

Research output: Contribution to journalArticlepeer-review

104 Scopus citations

Abstract

We conducted this study to determine whether physiological changes in potassium concentration affect free radical formation by vascular cells. We assessed the effects of potassium on reactive oxygen species formed by cultured endothelial and monocyte/macrophage cells or freshly isolated human white blood cells by cytochrome c reduction or luminol chemiluminescence, respectively. Reducing potassium concentration of endothelial cell media (normally 5.1 to 6.1 mmol/L) to 3.0 mmol/L exponentially increased the rate of cytochrome c reduction, up to 8.4-fold at 2 hours; raising potassium concentration to 5.5 or 7.0 mmol/L at 1 hour reduced the maximal rate of cytochrome c reduction by 86% or 93%. Subsequent studies were done 30 to 75 minutes after media change. Potassium reduced the rate of cytochrome c reduction by 49% (endothelial cells) to 55% (monocytes/macrophages) between 3.0 and 7.0 mmol/L; the greatest decrement (20% to 26%) occurred between 3.0 and 4.0 mmol/L. Superoxide dismutase reduced the rate of cytochrome c reduction by 62% or 50% in endothelial or monocyte/macrophage cells. Potassium had no effect on the rate of cytochrome c reduction in the presence of superoxide dismutase. Increasing potassium concentration from 1.48 to 4.77 or 7.94 mmol/L also reduced luminol chemiluminescence in human white blood cells challenged by 1 to 10 mg/mL zymosan. We conclude that physiological increases in potassium concentration inhibit the rate of superoxide anion formation by cell lines derived from endothelium and from monocytes/macrophages and reactive oxygen species formation by human white blood cells.

Original languageEnglish
Pages (from-to)77-82
Number of pages6
JournalHypertension
Volume24
Issue number1
DOIs
StatePublished - Jul 1994

Keywords

  • cell line
  • endothelium
  • free radicals
  • macrophages
  • monocytes
  • potassium
  • reactive oxygen species
  • superoxide anion

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