Leukocyte intracellular pH and Na/H antiporter activity in uraemia and type I diabetes mellitus.
The leukocyte Na/H antiporter has been studied in patients with end-stage renal failure on maintenance haemodialysis. Thirteen non-diabetic haemodialysis patients (CRF group) and eight haemodialysis patients with diabetic nephropathy (CRF-DM group) were investigated. Measurements were made using the pH-sensitive fluorescent dye bis (carboxyethyl) carboxyfluorescein (BCECF). The initial intracellular pH (pHi), intracellular buffering capacity, and Na/H antiporter Vmax (at pHi = 6.0) have been recorded in bicarbonate-free solutions. The mean initial intracellular pH in the CRF group was 7.34 (SD 0.05, P less than 0.004) and this was significantly less than the CRF-DM group (7.42, SD 0.07) and normal controls (7.43, SD 0.09, n = 25). The mean intracellular buffering capacity was normal in the CRF and CRF-DM groups. The mean Na/H antiporter Vmax was also normal in the CRF and CRF-DM groups (56.5, SD 9.9; and 56.8, SD 12.8, mmol/l per min respectively compared to 55.2, SD 8.8, mmol/l per min in controls). These data are discussed with reference to the reported high values of Na/H antiporter Vmax in diabetic patients with early nephropathy. This abnormality does not appear to be present in end-stage diabetic nephropathy.
Poli de Figueiredo
C E
CE
University Laboratory of Physiology, Oxford, UK.
Ng
L L
LL
Garrido
M C
MC
Davies
J E
JE
Ellory
J C
JC
Hendry
B M
BM
D000293:Adolescent; D000328:Adult; D000368:Aged; D002352:Carrier Proteins / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D003928:Diabetic Nephropathies / Q000097:blood; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007424:Intracellular Fluid / Q000378:metabolism; D007962:Leukocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D017923:Sodium-Hydrogen Exchangers; D014511:Uremia / Q000097:blood*
D002352:Carrier Proteins; D017923:Sodium-Hydrogen Exchangers