Elevated erythrocyte sodium-lithium counter-transport in hypertensive patients with non-insulin-dependent diabetes mellitus.
Increased erythrocyte (RBC) sodium-lithium (Na-Li) counter transport (CT) has been reported to be a genetic marker for essential hypertension (EHT). In addition, increased RBC Na-Li CT has been demonstrated in insulin-dependent diabetic (IDDM) patients with nephropathy, indicating that a predisposition to hypertension may cause renal damage and impaired renal function. Therefore, the present study was designed to determine RBC Na-Li CT in subjects with essential hypertension (EHT) and non-insulin-dependent diabetics (NIDDM) with or without hypertension (NIDDMHT or NIDDMNT), using the method of Canessa et al. with a slight modification by flame photometry and expressed as nmol Li/5 x 10(6) RBC/h. Na-Li CT in patients with EHT (0.159 +/- 0.051 (S.D.), n = 26) or NIDDMHT (0.168 +/0 0.083, n = 42) was higher than that in NIDDMNT patients (0.127 +/- 0.059, n = 27, P < 0.05). Among the NIDDMHT patients, those with clinical nephropathy had the same levels of Na-Li CT as those without nephropathy. When the NIDDM patients were divided into two groups with or without insulin treatment, the Na-Li CT in hypertensives was higher than that in normotensives, irrespective of whether or not they were on insulin therapy. Addition of insulin to RBCs in vitro did not augment the Na-Li CT activity. These results suggest that an increase of Na-Li CT may not be due to the stimulatory effect of endogenous or exogenous insulin, and reflect a genetic predisposition for hypertension, and hence diabetic nephropathy, not only in IDDM but also NIDDM patients.
Senda
T
T
Fourth Department of Medicine, Saitama Medical School, Japan.
Serizawa
N
N
Negishi
K
K
Katayama
S
S
D017920:Antiporters / Q000097:blood* / Q000187:drug effects; D001794:Blood Pressure; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000097:blood* / Q000503:physiopathology; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D008094:Lithium / Q000097:blood*; D008875:Middle Aged; D012016:Reference Values; D012964:Sodium / Q000097:blood
D017920:Antiporters; D007328:Insulin; C045885:sodium-lithium countertransporter; D008094:Lithium; D012964:Sodium