NMR studies of intracellular free calcium, free magnesium and sodium in the guinea pig reticulocyte and mature red cell

Linda A. Jelicks, Janet Weaver, Simeon Pollack, Raj K. Gupta

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


During the maturation process reticulocytes lose their intracellular organelles and undergo changes in membrane lipid composition and ion transport properties. While several reports indicate differences in the levels of magnesium, sodium and calcium in reticulocytes and erythrocytes, controversy remains concerning the actual magnitude and direction of ionic alterations during reticulocyte maturation. One problem with all of these studies is that the techniques used are invasive and are limited to measuring only the total cell ion content. We have used 31P, 23Na and 19F nuclear magnetic resonance (NMR) spectroscopy to compare the intracellular free ion and phosphometabolite levels in guinea pig reticulocytes and mature red blood cells. In contrast to a sharply decreased concentration of ATP in erythrocytes in comparison to reticulocytes, the intracellular free magnesium, measured using 31P-NMR, was increased by about 65% upon maturation (150 μmol/l cell water in reticulocytes in comparison to 250 μmol/l cell water in erythrocytes). Sizeable but opposite changes in intracellular sodium (5.5 μmol/ml cells in reticulocytes vs. 8.5 μmol/ml cells in erythrocytes) and intracellular free calcium (99 nM vs. 31 nM in reticulocytes and mature red cells, respectively) were also observed, suggesting that alterations in the kinetics of membrane ion transport systems, accompanying changes in phospholipid and cholesterol content, occur during the process of red cell maturation. However, in contrast to dog red blood cells, there was no evidence for the presence of a Na+/Ca2+ exchanger in guinea pig reticulocytes or erythrocytes.

Original languageEnglish (US)
Pages (from-to)261-266
Number of pages6
JournalBBA - Molecular Cell Research
Issue number3
StatePublished - Aug 15 1989
Externally publishedYes


  • (Guinea pig blood)
  • Calcium ion, intracellular
  • Erythrocyte
  • Magnesium ion, intracellular
  • Reticulocyte
  • Sodium ion, intracellular

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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