Platelet and erythrocyte Mg2+, Ca2+, Na+, K+ and cell membrane adenosine triphosphatase activity in essential hypertension in blacks

Touyz, R.M. , Milne, F.J. and Reinach, S.G. (1992) Platelet and erythrocyte Mg2+, Ca2+, Na+, K+ and cell membrane adenosine triphosphatase activity in essential hypertension in blacks. Journal of Hypertension, 10(6), pp. 571-578.

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Publisher's URL: http://journals.lww.com/jhypertension/Abstract/1992/06000/Platelet_and_erythrocyte_Mg2_,_Ca2_,_Na_,_K__and.10.aspx

Abstract

Objective: To assess the relationship between intracellular Mg2+, Ca2+, Na+ and K+ and cell membrane adenosine triphosphatase (ATPase) activity in normotensive and hypertensive blacks.

Design: Intracellular cations and cell membrane ATPase activity were studied in black patients with untreated essential hypertension and age-, weight- and height-matched normotensive controls. Platelet, erythrocyte and serum Mg2+, Ca2+, Na+ and K+ levels as well as platelet and erythrocyte membrane Na+, K+ -ATPase, Ca2+ -ATPase and Mg2+-ATPase activities were measured in all subjects.

Methods: Intracellular Na+ and K+ were measured by flame photometry and Mg+ and Ca+ by atomic absorption spectrophotometry. Cell membrane ATPase activity was determined by a colorimetric method.

Results: The hypertensive group consistently demonstrated depressed activity of each ATPase studied, with significantly lower serum Mg2+, serum K+, erythrocyte Mg2+ and platelet Mg2+ levels compared with the normotensive group. Platelet Na+ and Ca2+ and erythrocyte Ca2+ were significantly elevated in the hypertensive group. In the hypertensive group, mean arterial pressure (MAP) was inversely correlated with platelet and erythrocyte membrane Na+, K+ -ATPase, Ca2+-ATPase and Mg2+-ATPase. Serum Mg2+, serum Ca2+ and platelet Mg2+ were negatively correlated with MAP in the hypertensive group whilst erythrocyte and platelet Ca2+ were positively correlated. In the normotensive group, platelet Mg2 + and MAP were negatively, and erythrocyte Ca2+ and MAP, positively correlated.

Conclusions: Black patients with essential hypertension have widespread depression of cell membrane Na+, K+ -ATPase, Ca2+-ATPase and Mg2+-ATPase activities with serum and intracellular Mg2+ depletion and cytosolic Na+ and Ca2+ overload, which may reflect an underlying membrane abnormality in essential hypertension. These cellular abnormalities may be related to the defective transport mechanisms that in turn may be aggravated by Mg2+ depletion.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Touyz, Professor Rhian
Authors: Touyz, R.M., Milne, F.J., and Reinach, S.G.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Journal Name:Journal of Hypertension
ISSN:0263-6352
ISSN (Online):1473-5598

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