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[Na+, K+, Cl-]-cotransport function and dysfunction in different forms of primary hypertension.
M N Saitta1, P A Hannaert, C Rosati
1INSERM U7/CNRS LA 318, Hôpital Necker, Paris, France.
American Journal of Hypertension
|July 1, 1988
Summary
The [Na+, K+, Cl-]-cotransport system in human red blood cells acts as a "second pump." Increased cell sodium enhances outward transport, potentially influencing primary hypertension.
Area of Science:
- Physiology
- Cell Biology
- Biochemistry
Background:
- The [Na+, K+, Cl-]-cotransport system plays a crucial role in cellular ion balance.
- Understanding its function in human erythrocytes provides insights into broader cellular mechanisms.
Purpose of the Study:
- To investigate how elevated intracellular sodium affects the [Na+, K+, Cl-]-cotransport system in human erythrocytes.
- To explore the potential roles of this cotransporter in primary hypertension.
Main Methods:
- Human erythrocytes were incubated in Li-Rb media to manipulate intracellular sodium content.
- Outward and inward unidirectional fluxes of ions mediated by the cotransporter were measured.
Main Results:
- Low intracellular sodium led to uncoupled potassium efflux.
- Increased cell sodium significantly stimulated outward Na+, K+ cotransport more than inward Li+, Rb+ cotransport.
- Stoichiometries were observed to be close to one-to-one.
Conclusions:
- The [Na+, K+, Cl-]-cotransport system can function as a "second pump" in erythrocytes, utilizing energy from net K+, Cl- efflux.
- This system may act as a "defective second pump" or a "compensatory second pump" in primary hypertension, depending on the specific cellular ion transport abnormalities.