title: Red cell Na+/Li+ countertransport in non-insulin-dependent diabetics with diabetic nephropathy.
abstract: Genetic predisposition to essential hypertension, as indicated by increased maximal velocity of Na+/Li+ countertransport in red cells, has been suggested as a marker for the risk of developing diabetic nephropathy. To evaluate the validity of this concept in non-insulin-dependent diabetics, we measured the maximal velocity of Na+/Li+ countertransport in red cells in 18 male diabetics suffering from proteinuria due to biopsy proven diabetic glomerulosclerosis (GFR: 51 [range 27 to 146] ml/min/1.73 m2), 17 male diabetics with normoalbuminuria, and in 18 sex-, age-, and body mass index-matched healthy control subjects. Na+/Li+ countertransport was identical in patients with and without diabetic nephropathy, 0.43 (0.24 to 0.92) versus 0.44 (0.20 to 0.83) mmol/(liter cells x hr), but was elevated compared to control subjects, 0.32 (0.09 to 0.73; P less than 0.05). Arterial blood pressure was elevated in patients with nephropathy (162/92 +/- 21/9 mm Hg) compared to normoalbuminuric patients (132/82 +/- 15/7) and control subjects (133/83 +/- 14/7 mm Hg; P less than 0.001). Our study does not support the hypothesis that the risk of diabetic nephropathy in non-insulin-dependent diabetes is associated with a genetic predisposition to hypertension. Diabetes per se seems to enhance Na+/Li+ countertransport activity.
authors.affiliation: Hvidöre Hospital, Klampenborg, Denmark.
authors.forename: M A
authors.initials: MA
authors.lastname: Gall
authors.forename: P
authors.initials: P
authors.lastname: Rossing
authors.forename: J S
authors.initials: JS
authors.lastname: Jensen
authors.forename: J
authors.initials: J
authors.lastname: Funder
authors.forename: H H
authors.initials: HH
authors.lastname: Parving
mesh_terms: D017920:Antiporters; D002352:Carrier Proteins / Q000097:blood*; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D003928:Diabetic Nephropathies / Q000097:blood* / Q000453:epidemiology; D004912:Erythrocytes / Q000378:metabolism*; D005069:Evaluation Studies as Topic; D006801:Humans; D006973:Hypertension / Q000235:genetics; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
chemical_list: D017920:Antiporters; D002352:Carrier Proteins; C045885:sodium-lithium countertransporter