Étude de la glycolyse et de la perméabilité des érythrocytes aux ions orthophosphates dans le rachitisme vitamino-résistant hypophosphatémique héréditaire

Cartier, P; Leroux, Jean‐Paul; Balsan, S; Royer, P.

doi:10.1016/0009-8981(70)90046-x

Cited by 7 publications

(3 citation statements)

References 27 publications

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“…2). The distribution ratio in vitro is similar to the steady-state chemical distribution ratio observed in vivo in the present study and elsewhere (18,19). The observed values correspond closely to the Donnan equilibrium for phosphate which we have calculated for the combined monovalent and divalent species of phosphate anion.…”

Section: Discussionsupporting

confidence: 91%

“…Under all conditions, Pi transfer across the erythrocyte membrane was similar in X-LH patients and in normal subjects. However, phosphate pools in the erythrocyte are significantly depleted in hypophosphatemic X-LH patients (19) and under such conditions the relative rates of Pt entry have been reported to be greater than normal in the glycolyzing X-LH erythrocyte (19). We were careful to carry out our studies in the presence of iodoacetamide so that entry into the intracellular orthophosphate pool alone would be compared in control subjects and in patients.…”

Section: Discussionmentioning

confidence: 99%

“…First, the whole-blood partial-pressure of oxygen at 50% saturation (P5o) is low in the X-LH patient with marked hypophosphatemia (5). Secondly, the concentrations of 2,3-diphosphoglycerate and total organic phosphate are diminished in the erythrocytes in children with hereditary hypophosphatemic states (19). Oral administration of phosphate in doses sufficient to raise the phosphate concentration in serum above 1 mM, restores P50 to normal in X-LH subjects (5).…”

Section: Discussionmentioning

confidence: 99%

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Orthophosphate transport in the erythrocyte of normal subjects and of patients with X-linked hypophosphatemia.

Tenenhouse¹,

Scriver²

1975

J. Clin. Invest.

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A B S T R A C T We have examined the mechanism of TCA-soluble orthophosphate (P.) transfer across the membrane of mature human erythrocytes in normal subjects and in patients with X-linked hypophosphatemia (X-LH). The studies were carried out largely at pH 7.4 and 370C, in partial simulation of conditions in vivo. (a) At physiological concentrations (1-2 mM) P. enters the intact normal erythrocyte down its chemical gradient and under no conditions could we identify a steady-state trans-membrane gradient for Pi greater than 0.6. Calculations of the phosphate anion distribution ratio using the Nernst equation yield theoretical values that closely approximate observed values. (b) Glycolytic inhibitors have little effect on total entry of 'P, into erythrocytes but they do affect the intracellular distribution of P.. In the presence of iodoacetamide, label accumulates almost exclusively in the orthophosphate pool and less than 1% enters the organic phosphate pool. (c) Specific activity measurements in unblocked cells indicate that P. anion equilibrates first with its intracellular P. pool. These initial findings imply that neither group translocation, nor energy coupling, influence P. permeation into the human erythrocytes. (d) The relationship between 'P entry and extracellular P. concentration is parabolic in the presence of chloride, and linear in the presence of sulfate.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%