RELATIONSHIP OF NA-K-ATPASE INHIBITORS TO BLOOD-PRESSURE REGULATION IN CONTINUOUS AMBULATORY PERITONEAL-DIALYSIS AND HEMODIALYSIS

Inhibitors of sodium-potassium-activated adenosine triphosphatase (Na- K-ATPase) have been implicated in the pathogenesis of hypertension. In the study presented here, an attempt was made to determine whether di fferences in the plasma levels and the removal rates of high-molecular weight (HMW) and low-molecular weight (LMW) forms of Na-K-ATPase inhi bitors might relate to blood-pressure control in hemodialysis (N = six ultrafiltered and N = six non-ultrafiltered) and CAPD (N = six long-t erm and N = five short-term) patients. The latter group was studied be fore the initiation of continuous ambulatory peritoneal dialysis (CAPD ) and 2 wk after starting the treatment. The mean blood pressure was s ignificantly reduced after dialysis in the non-ultrafiltered hemodialy sis group and in both CAPD groups. Plasma levels of both HMW and LMW i nhibitors were found to be elevated before dialysis in all patients an d were modified only slightly after dialysis, irrespective of whether ultrafiltration was utilized in hemodialysis patients and despite sign ificant losses of both HMW and LMW inhibitors into CAPD effluent, Beca use CAPD effluent was found to contain vasopressors that were not excl usively Na-K-ATPase inhibitors, losses of these other vasopressors may contribute to improved blood-pressure control in CAPD in contrast to hemodialysis.