Increased membraneous calcium concentrations in primary hypertension: a causal link to pathogenesis?
BACKGROUND
Disturbance in calcium metabolism has been suggested in the pathogenesis of hypertension, however, membrane calcium content in humans has not been studied in detail yet in primary hypertension. We compared plasma, intracellular and membrane calcium concentrations in erythrocytes of patients with essential hypertension and in healthy, normotensive control subjects to determine a possible alteration of membrane calcium in primary hypertension.


METHODS
Thirty-four never treated patients with essential hypertension were included and 34 healthy, age- and sex-matched volunteers served as controls. Atomic absorption spectroscopy was used for measurement of intracellular and membrane calcium content in erythrocytes and plasmalemmal preparations.


RESULTS
Plasma and intracellular Ca(++) concentrations were not significantly different between hypertensives and controls (plasma: 2.59 +/- 0.18 vs2.50 +/- 0.16 mmol/l, intracellular: 1.89 +/- 0.20 mmol/l vs 1.97 +/- 0.24 mmol/l, NS resp., mean +/- s.e.m.). However, membrane calcium content was significantly higher in hypertensive patients compared to control subjects (2.38 +/- 0.28 micromol/g membraneous protein vs0.86 +/- 0.32 micromol/g membrane protein, P < 0.01). Membrane calcium content was correlated to mean arterial blood pressure (r = 0.59, P < 0.01).


CONCLUSIONS
Membrane calcium content is significantly increased in patients with untreated primary hypertension and correlates to blood pressure levels. This data suggest, that an membrane mechanism may contribute to alterations in calcium metabolism and to the pathogenesis of primary hypertension.
Department of Internal Medicine D, University of Münster, D-48129 Münster, Germany. koschm@uni-muenster.de
M
M
Kosch
M
M
Hausberg
M
M
Barenbrock
A
A
Posadzy-Malaczynska
K H
KH
Rahn
K
K
Kisters
D000328:Adult; D002118:Calcium / Q000097:blood*; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000209:etiology; D007425:Intracellular Membranes / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D012016:Reference Values
D002118:Calcium