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- Title
A circulating inhibitor of the RBC membrane calcium pump in chronic renal failure.
- Authors
Lindner, Armando; Gagne, Eve-Reine; Zingraff, Johanna; Jungers, Paul; Drijeke, Tilman B.; Hannaert, Patrick; Garay, Ricardo; Lindner, A; Gagne, E R; Zingraff, J; Jungers, P; Drüeke, T B; Hannaert, P; Garay, R
- Abstract
A humoral inhibitor of the membrane calcium pump was studied in plasma from 28 normal controls, 33 patients receiving long-term hemodialysis, and 26 with chronic renal failure (CRF; creatinine clearance range was 6 to 97 ml/min). Calcium pump activity was measured as the rate of Sr2+ efflux in normal erythrocytes (RBCs) loaded with Sr2+ (a substitute of Ca2+ in the calcium pump). Plasma, and plasma ultrafiltrates from hemodialysis patients strongly inhibited calcium pump activity compared with controls without plasma (36 +/- 18 vs. 25 +/- 12, %INHIBITION/CONTROL, P < 0.05). Inhibition markedly decreased with acute hemodialysis (16 +/- 12 vs. 5 +/- 14, %INHIBITION/NORMAL PLASMA, N = 15, P < 0.001). In CRF, degree of inhibition correlated with the serum creatinine concentration (r = 0.75, P < 0.001). A kinetic study showed that plasma decreased the maximal rate of the Ca2+ pumps (Vmax) without affecting the apparent affinity for internal cations (KSr). Moreover, the plasma inhibitory factor had a low molecular weight, and was dialyzable and heat stable. In conclusion, we found evidence for an RBC membrane calcium pump inhibitor in uremic plasma, which correlates with the degree of renal insufficiency. Possibly, it may increase calcium content in RBCs and other cells and could thus be related to uremic toxicity and/or hypertension.
- Subjects
BLOOD plasma; CHRONIC kidney failure; HEMODIALYSIS; CALCIUM; HYPERTENSION; TREATMENT of chronic kidney failure; ERYTHROCYTE metabolism; BIOLOGICAL transport; CARRIER proteins; COMPARATIVE studies; DYNAMICS; RESEARCH methodology; MEDICAL cooperation; RESEARCH; EVALUATION research; IN vitro studies
- Publication
Kidney International, 1992, Vol 42, Issue 6, p1328
- ISSN
0085-2538
- Publication type
journal article
- DOI
10.1038/ki.1992.424