Abstract

Background—Nitric oxide (NO) is a potent chemical mediator involved in many functions. In vivo production of NO is thought to be regulated by endogenous analogues of L-arginine: asymmetric dimethylarginine (ADMA).

Aim—To examine the effect of renal function and dialysis on the serum concentrations of ADMA and symmetric dimethylarginine (SDMA).

Methods—Blood samples were obtained from nine healthy subjects, patients with renal failure before (n = 17) and after haemodialysis (n = 9), nine patients on chronic ambulatory peritoneal dialysis (CAPD), and 13 patients with chronic renal failure on conservative treatment. Serum samples were extracted using a solid phase cation exchange column and the extracts were analysed by high performance liquid chromatography (HPLC).

Results—Serum concentrations of ADMA in patients with renal failure (mean, 1.04 μmol/litre; SD, 0.17) were significantly higher than those of controls (mean, 0.61 μmol/litre; SD, 0.13). Haemodialysis significantly decreased the serum concentration by 36% (before dialysis: mean 0.99 (SD, 0.25) μmol/litre; after dialysis: mean, 0.63 (SD, 0.15) μmol/litre). Serum SDMA concentrations were higher in patients with renal failure, and haemodialysis decreased the concentration by 60%. There was no difference in serum arginine concentrations between the groups.

Conclusion—Serum concentrations of ADMA are increased in renal failure and haemodialysis reduces the concentration.