Red blood cell Na+, K+-ATPase in men with newly diagnosed or previously treated essential hypertension

Richard E. Ringel, John M. Hamlyn, Bruce P. Hamilton, Gerard A. Pinkas, Stuart A. Chalew, Michael A. Berman

Research output: Contribution to journalArticlepeer-review

Abstract

Alterations of cellular function of Na+, K+-edenosine triphosphatase (ATPase; Na+-K+ pomp) have been implicated in the pathophyslology of essential hypertension. Therefore, this aspect of red blood cell (RBC) Na metabolism was studied in black men with newly diagnosed, untreated essential hypertension (NEH) and a normotensive control group. RBC Na content, Na+-K+ pump number (ouabain binding sites), and pomp activity were measured. No statistically significant differences were found between the two groups for any of these three parameters. However, a group of previously treated essential hypertensive subjects (PEH) who had been withdrawn from therapy in the preceding 6 weeks were also studied. This group differed significantly from the NEH subjects in regard to all RBC Na+-K+ pump parameters. Their RBC Na content (10.27 ± 3.23 vs 7.77 ± 2.52 mmol Na/L RBC; p = 0.006) was higher, and their Na+-K+ pump activity (166 ± 50 vs 221 ± 87 nmol inorganic phosphate/mg membrane protein/hr; p = 0.03) and Na+-K+ pump number (213 ± 40 vs 284 ± 85 binding sites/RBC; p = 0.001) were lower compared with those in NEH subjects. Although the PEH subjects were older and somewhat less hypertensive than their NEH counterparts, these factors were not found to influence the Na+-K+ pump parameters. These results indicate that chronic diuretic therapy of patients with essential hypertension is associated with a reduced number of RBC Na+-K+ pumps, Since RBCs are not considered target cells for diuretics, the effects of these drugs on RBC electrolyte metabolism may occur at the time of erythropoiesis by the production of RBCs with fewer Na+-K+ pumps. Furthermore, the finding of elevated RBC Na content in PEH subjects acutely withdrawn from diuretic therapy is compatible with the renewed production of an endogenous natriuretic hormone that functions as a Na+-K+ pump inhibitor.

Original languageEnglish (US)
Pages (from-to)437-443
Number of pages7
JournalHypertension
Volume9
Issue number5
DOIs
StatePublished - May 1987
Externally publishedYes

Keywords

  • Diuretics
  • Essential hypertension
  • K-adenosine triphosphatase
  • Na
  • Ouabain
  • Sodium

ASJC Scopus subject areas

  • Internal Medicine

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