Clinical application of sodium-23 nuclear magnetic resonance for measurement of red cell sodium concentrations.
Red cell sodium (RBC-Na+) concentrations were measured using 23Na nuclear magnetic resonance (NMR), without the destruction of erythrocyte membranes. Subjects were categorized into four groups: 20 normotensive subjects (NT group), 20 age-matched essential hypertensive patients (EHT group), 10 patients with primary aldosteronism (PA group), and 18 patients treated with digoxin (DIG group). Although RBC-Na+ concentrations were similar between the NT group (6.14 +/- 0.80 (Mean +/- SD) mmol/l) and the EHT group (5.92 +/- 0.99), they were significantly higher in both the PA group (7.55 +/- 0.88, p less than 0.001) and the DIG group (8.43 +/- 3.81, p less than 0.02). In the PA group, RBC-Na+ concentrations decreased significantly after resection of the adenoma, and there was an inverse relationship between serum potassium and RBC-Na+ concentrations (r = -0.65, p less than 0.01). In the DIG group, RBC-Na+ concentrations tended to increase in proportion to serum digoxin levels (r = 0.53, p less than 0.05). These results support the view that RBC-Na+ concentrations are determined primarily by Na+/K+-pump activity of red cell membranes. This study showed also that Na+ NMR is an useful method determining intracellular Na+ concentrations.
Kojima
S
S
Department of Medicine, National Cardiovascular Center Hospital, Osaka, Japan.
Kanashiro
M
M
Hayashi
F
F
Yoshida
K
K
Abe
H
H
Imanishi
M
M
Kawamura
M
M
Kawano
Y
Y
Ashida
T
T
Kimura
G
G
D004077:Digoxin / Q000097:blood; D004912:Erythrocytes / Q000032:analysis*; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000097:blood; D006973:Hypertension / Q000097:blood; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D011188:Potassium / Q000097:blood; D012964:Sodium / Q000097:blood*
D004077:Digoxin; D012964:Sodium; D011188:Potassium