Scientific Results

Erythrocyte sodium pump stimulation by ouabain and an endogenous ouabain-like factor

Year: 2007

Authors: Balzan, S.; D’Urso, G.; Nicolini, G.; Forini, F.; Pellegrino, M.; Montali, U.

Autors Affiliation: CNR Institute of Clinical Physiology, Via Moruzzi 1, Pisa, Italy.
Department of Human and Environmental Sciences, Via Roma 55, Pisa, Italy.
Department of Physiology and Biochemistry ‘G. Moruzzi’, University of Pisa, via San Zeno 31, Pisa, Italy

Abstract: Cardiac glycosides inhibit the sodium pump. However, some studies suggest that nanomolar ouabain concentrations can stimulate the activity of the sodium pump.
In this study, using the Na+/K+-ATPase of human erythrocytes, we compared the effect of digoxin, ouabain and an ouabain like-factor (OLF), on Rb-86 uptake.
Ouabain concentrations below 10(-9) M significantly stimulate Rb+ uptake, and the maximal increase above base-line values is 18 +/- 5% at 10(-10) M ouabain. No stimulation is observed in the same conditions by digoxin. OLF behaved like ouabain, producing an activation of Rb+ flux at concentrations lower than 10(-9) M ouabain equivalents (14 +/- 3% at 10(-10) M).
Western blot analysis revealed the presence of both alpha(1) and alpha(3) pump isoforms in human erythrocytes. Our data confirm the analogies between OLF and ouabain and suggest that Na+/K+-ATPase activation may be related to the alpha(3) isoform.
In addition, we investigated whether ouabain at different concentrations was effective in altering the intracellular calcium concentration of erythrocytes. We found that ouabain at concentration lower than 10-9 M did not affect this homeostasis.


Volume: 25 (3)      Pages from: 297  to: 303

KeyWords: Na+/K+-ATPase; cardiac glycoside; endogenous ouabain-like factor; calcium imaging; erythrocyte
DOI: 10.1002/cbf.1387

Citations: 12
data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2022-01-16
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