Na⁺/H⁺ Exchange in Patients with Mild Chronic Renal Failure

Abstract

Cytosolic pH (pH_i) and Na⁺/H⁺ exchange activity were measured in lymphocytes from 22 patients with mild chronic renal failure, and 21 age- and sex-matched normotensive healthy control subjects using the fluorescent dye technique. The basal pH_i in resting lymphocytes was not significantly different in both groups tested (control, pH_i 7.18 ± 0.04; patients with mild chronic renal failure, 7.17 ± 0.05). The initial rate of pH_i recovery immediately after intra-cellular acidification with 100 mmol/l propionic acid, representing the maximum Na⁺/H⁺ exchange activity, was significantly higher in lymphocytes from patients with mild chronic renal failure (7.10 ± 0.52 dpHi/s, mean ± SEM) when compared with control subjects (5.42 ± 0.47 dpH_i/s; p < 0.05). No significant correlation between Na⁺/H⁺ exchange activity and blood pressure could be obtained in patients with mild chronic renal failure. Furthermore, there was no relationship of Na⁺/H⁺ exchange activity to cytosolic pH or extracellular pH. It is concluded that an enhanced Na⁺/H⁺ exchange activity can be detected in patients with mild chronic renal failure and may not be related to the significant abnormalities of electrolyte and acid-base metabolism commonly observed in patients with end-stage renal failure or on hemodialysis.