ABSTRACT
It is still controversial whether endogenous nitric oxide production is increased or decreased in patients with endnstage renal disease and whether haemodialysis affect the concentration of serum nitric oxide or not. The study was designed to assess serum nitric oxide concentration in chronic renal failure patients and to evaluate its possible affection by haemodialysis. Twenty patients with endnstage renal disease and maintained regular haemodialysis were included in the study and matched against ten healthy volunteers. Total serum nitric oxide concentration was measured colourimetrically three times for patients [Just pre- and post haemodialysis sessions and then one day after haemodialysis] and once for controls. Serum nitric oxide concentration was found significantly decreased in chronic renal failure patients before haemodialysis session and its level was correlated negatively with levels of blood urea and serum creatinine and correlated positively with creatinine clearance value. The serum nitric oxide concentration significantly increased immediately and one day after haemodialysis session regardless the type of dialyzed membrane usned. This increase was temporary and the level significantly declined as the dialysis effect withdrawn. It is concluded that nitric oxide production decreased in uraemic patients, possibly due to accumulation of endogenous inhibitors to nitric oxide synthase and haemodialysis increases nitric oxide production temporary by reducing the concentration of such inhibitors