Nephropathy and changes in sodium-lithium countertransport kinetics in type 2 (non-insulin-dependent) diabetes mellitus.
Previous studies of erythrocyte sodium-lithium countertransport activity, a putative genetic marker of essential hypertension, in Type I and Type II diabetic patients with nephropathy have given conflicting results. We have found changes in the maximum velocity (Vmax) and sodium-affinity constant (Km) of sodium-lithium countertransport in Type I diabetic patients with diabetic nephropathy. In this study, sodium-lithium countertransport kinetics were measured in Type II diabetic patients with established diabetic nephropathy, matched uncomplicated Type II diabetic patients, non-diabetic patients with nephropathy and healthy control subjects. Mean standard sodium-lithium countertransport activity was not significantly increased in either of the groups of diabetic patients compared with the non-diabetic control groups. The Type II diabetic patients with nephropathy had a significantly reduced km and Vmax compared with the uncomplicated diabetic patients and non-diabetic control group. These kinetic changes are identical to those observed in Type I diabetic nephropathy patients. There are similar underlying changes in the erythrocyte plasma membrane with the development of nephropathy in both Type I and Type II diabetes.
Rutherford
P A
PA
Department of Medicine (Nephrology), Freeman Hospital, Newcastle-Upon-Tyne, UK.
Thomas
T H
TH
Taylor
R
R
Wilkinson
R
R
D017920:Antiporters / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000378:metabolism*; D003928:Diabetic Nephropathies / Q000209:etiology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D012016:Reference Values
D017920:Antiporters; C045885:sodium-lithium countertransporter