Normal Ca2+ extrusion by the Ca2+ pump of intact red blood cells exposed to high glucose concentrations

1  Department of Physiology, Monash University, Victoria 3800, Australia; 2  Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461; and 3  Physiological Laboratory, University of Cambridge, Cambridge CB2 3EG, United Kingdom The ATPase activity of the plasma membrane Ca 2...

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Published in:American Journal of Physiology: Cell Physiology 2001-06, Vol.280 (6), p.C1449-C1454
Main Authors: Raftos, Julia E, Edgley, Amanda, Bookchin, Robert M, Etzion, Zipora, Lew, Virgilio L, Tiffert, Teresa
Format: Article
Language:English
Subjects:
Animals
Calcium - metabolism
Calcium-Transporting ATPases - metabolism
Diabetes Mellitus, Experimental - metabolism
Erythrocyte Membrane - enzymology
Erythrocytes - drug effects
Erythrocytes - enzymology
Glucose - pharmacology
Glycated Hemoglobin A - metabolism
Humans
Male
Rats
Rats, Wistar
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Summary:1  Department of Physiology, Monash University, Victoria 3800, Australia; 2  Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461; and 3  Physiological Laboratory, University of Cambridge, Cambridge CB2 3EG, United Kingdom The ATPase activity of the plasma membrane Ca 2+ pump (PMCA) has been reported to be inhibited by exposure of red blood cell (RBC) PMCA preparations to high glucose concentrations. It has been claimed that this effect could have potential pathophysiological relevance in diabetes. To ascertain whether high glucose levels also affect PMCA transport function in intact RBCs, Ca 2+ extrusion by the Ca 2+ -saturated pump [PMCA maximal velocity ( V max )] was measured in human and rat RBCs exposed to high glucose in vivo or in vitro. Preincubation of normal human RBCs in 30-100 mM glucose for up to 6 h had no effect on PMCA V max . The mean V max of RBCs from 15 diabetic subjects of 12.9 ± 0.7 mmol · 340 g Hb 1 · h 1 was not significantly different from that of controls (14.3 ±   0.5 mmol · 340 g Hb 1 · h 1 ). Similarly, the PMCA V max of RBCs from 11 streptozotocin-diabetic rats was not affected by plasma glucose levels more than three times normal for 6-8 wk. Thus exposure to high glucose concentrations does not affect the ability of intact RBCs to extrude Ca 2+ . plasma membrane calcium pump; glycation; diabetes mellitus; streptozotocin
ISSN:0363-6143
1522-1563
DOI:10.1152/ajpcell.2001.280.6.C1449