Endothelin in renal failure.

Endothelin is a 21-residue peptide vasoconstrictor produced by endothelium. Using a radioimmunoassay, endothelin values were measured in four groups of individuals: normal controls (0.54 +/- 0.12 pmol/l, n = 20); undialysed patients with chronic renal failure (CRF) (0.82 +/- 0.13 pmol/l, n = 38); chronic renal failure patients on continuous ambulatory peritoneal dialysis (CAPD) (2.81 +/- 0.63 pmol/l, n = 20); and patients with CRF on haemodialysis (HD) (4.52 +/- 1.21 pmol/l, n = 14). The endothelin values were significantly greater in undialysed patients with CRF when compared with controls (P less than 0.001) and significantly greater in both dialysis groups when compared with controls and the undialysed CRF group (P much less than 0.001). The difference between the two dialysis groups was not significant (P = 0.07). There was no correlation between endothelin and serum creatinine, mean arterial pressure, presence of chronic hypertension and/or diabetes, use of calcium-channel blockers and/or ACE inhibitors, or primary renal diagnostic category. A single haemodialysis session had no significant effect on endothelin values in the ten patients in whom this was assessed. Fast protein liquid chromatography (FPLC) appeared to confirm that the molecular species found in chronic renal failure were the same as those found in diabetic patients.