Elevated erythrocyte sodium-lithium countertransport activity correlates with increased intracellular sodium and free calcium-ion concentration in type 2 diabetes.
To explore the mechanism by which elevated sodium-lithium countertransport activity (SLC) associates with both predisposition to hypertension and diabetic nephropathy, we investigated the interrelationships among SLC, intracellular sodium concentration ([Na]i), intracellular free calcium-ion concentration ([Ca2+]i), diabetic nephropathy, hypertension, family history of hypertension, and other factors in 48 patients with Type 2 diabetes and 24 healthy controls. There was a significant correlation between SLC and [Na]i (r = 0.36, p < 0.05), [Na]i and [Ca2+]i (r = 0.47, p < 0.01), SLC and [Ca2+]i (r = 0.46, p < 0.01), and between HbA1c and [Ca2+]i (r = 0.38, p < 0.01). Both [Na]i and [Ca2+]i were significantly higher in the patients with elevated SLC than in those with normal SLC (p < 0.01 and p < 0.05, respectively). In stepwise multivariate regresssion analysis, [Na]i, HbA1c, and SLC appeared as independent determinants of [Ca2+]i. These data suggest a significant correlation of elevated SLC with increased [Na]i and [Ca2+]i. This may be a possible mechanism underlying the close association of elevated SLC with both predisposition to hypertension and diabetic nephropathy.
Fujita
J
J
Department of Metabolism and Clinical Nutrition, Kyoto University, Japan.
Tsuda
K
K
Seno
M
M
Obayashi
H
H
Fukui
I
I
Seino
Y
Y
D000328:Adult; D001794:Blood Pressure; D002118:Calcium / Q000097:blood*; D008076:Cholesterol, HDL / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000097:blood / Q000503:physiopathology; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D006973:Hypertension / Q000150:complications; D008094:Lithium / Q000097:blood; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012016:Reference Values; D012044:Regression Analysis; D012964:Sodium / Q000097:blood*; D014280:Triglycerides / Q000097:blood
D002118:Calcium; D008076:Cholesterol, HDL; D006442:Glycated Hemoglobin; D008094:Lithium; D012964:Sodium; D014280:Triglycerides