| Sodium and calcium transport in spherocytic red blood cells. |
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Shin Heh Kang1, Kir Young Kim1, Young Ho Lee2, Bok Soon Kang2 |
1Department of Pediatrics, College of Medicine, Yonsei University, Seoul, Korea
2Department of Physiology, College of Medicine, Yonsei University, Seoul, Korea |
| 구상 적혈구막을 통한 Na+과
Ca++ 이동에 관한 연구 |
|
강신혜1, 김길영1, 이영호2, 강복순2 |
1연세대학교 의과대학 소아과학교실
2연세대학교 의과대학 생리학교실 |
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Received: 24 April 1991 • Accepted: 28 May 1991 |
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| Abstract |
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Hereditary spherocytosis (HS) is an autosomal, dominantly inherited hemolytic disorder which
shows characteristic spherocytes on peripheral smear. As spherocytes are rounder, more fragile and
susceptible to extravascular hemolysis in the spleen, HS patients suffer from variable degrees of
anemia, jaundice, splenomegaly and gall stones. However the pathogenesis is heterogenous in HS,
such as spectrin deficiency, decreased spectrin-protein 4.1 binding, increased spectrin binding to the
RBC membrane, defective microfilament formation, altered membrane protein phosphorylation and
abnormal cation transport. In an attemp to clarify the abnormalities of cation transport in spher-
ocytes, we measured osmotic fragility, Na+-K+-ATPase and Ca++-ATPase activities of RBC mem-
brane, calcium binding to the red blood cell membrane fragment (RBCMF) and calcium efflux
between spherocytic red blood cells (hereditary spherocytosis; HS, themal induced spherocyte; TIS,
chlorpromazine induced spherocyte; CIS) and normal RBC (NB). The results were 1) The osmotic
fragility curves of TIS, CIS and HS shifted to the left in NaCl solution compared with that of NB
indicating increased osmotic fragility of spherocytic cells. 2) When RBC was incubated in 0.3M
sucrose for 12 hours to deplete sodium and other electrolytes, there was no difference in the osmotic
fragility in sucrose solution among TIS, CIS and NB. The osmotic fragility curves of TIS and CIS
shifted slightly to the left in NaCl solution, which became more evident when RBC was incubated in
sodium containing Tyrode solution. The osmotic fragility of ouabain incubated normal RBC was
increased compared to control RBC. 3) The osmotic fragility curve of RBC incubated with calcium
(1 mM) or calcium (1 mM) and vanadate (1 mM) shifted to the right compared with that of normal
RBC indicating decreased osmotic fragility. 4) The amount of calcium bound to RBCMF in TIS, CIS
and HS was significantly decreased compared with that of NB. 5) The Na+-K+-ATPase and Ca++-
ATPase activities of TIS, CIS and HS RBCMF were significantly decreased compared with that of
NB. 6) The calcium efflux of TIS, CIS and HS measured by calcium selective electrode was
markedly decreased compared with that of NB.
These data suggest that the decreased calcium efflux of TIS, CIS and HS is related to the decreased
Ca++-ATPase activity, and the increased osmotic fragility of TIS, CIS and HS seems to be due to
increased intracellular sodium resulting from decreased Na+-K+-ATPase activity. |
| Key Words:
Spherocyte, sodium transport, calcium transport |
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