1. The present report focuses on some aspects of the intra-erythrocytic cation metabolism (e.g. the maximal velocity of the Na+–Li+ countertransport and Na+/K+/Cl−1 cotransport) in uraemic patients on different dialysis treatments.
2. Patients undergoing dialysis treatment [continuous ambulatory peritoneal dialysis (CAPD) or haemodialysis (HD)] overall showed higher Na+–Li+ countertransport than controls. With regard to Na+/K+/Cl−1 cotransport, CAPD patients and controls did not differ and both showed, on average, higher values than HD patients.
3. A subgroup of HD patients was studied before and after dialysis. No significant overall changes were detected as a result of the dialysis process with regard to Na+/K+/Cl−1 cotransport. Na+-Li+ countertransport was significantly reduced by dialysis and a distinctly different response to dialysis was evident according to predialysis values. Patients with high values of Na+–Li+ countertransport showed a significant reduction in this parameter while patients with normal values showed no effect. No distinct association was detected between alteration in either Na+–Li+ countertransport or Na+/K+/Cl−1 cotransport and the clinical characteristics of the patients.
4. It is concluded that uraemia and/or dialysis influences the maximal velocity of the parameters under investigation. The effect on Na+–Li+ countertransport seems to be similar for both CAPD and HD, while Na+/K+/Cl−1 cotransport is not altered in CAPD patients.