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Characterization of Na+/H+ Antiporter Activity in PC-Cl3 Thyroid Cells.
- Source :
-
Cellular Physiology & Biochemistry (Karger AG) . 2003, Vol. 13 Issue 4, p207-214. 8p. 1 Chart, 6 Graphs. - Publication Year :
- 2003
-
Abstract
- Background/Aims: In thyroid cells, the intracellular pH plays a key role in the control of the iodide uptake, since iodide accumulation is associated with an intracellular acidification. In the present paper we studied the kinetic proprieties of the Na+/H+ antiporter (NHE) and the molecular expression of different NHE isoforms in rat thyroid PC-Cl3 cells. In addition the intracellular buffer capacity was also evaluated. Methods: pHi was measured using the pH sensitive fluorescent dye BCECF-AM. Amiloride, 5-(N,NDimethyl) hydrochloride was used to inhibit NHE activity. RT-PCR and western blot analyses were used to study the expression of NHE mRNA and protein isoforms. Results: PC-Cl3 cells shown a resting pHi, in the absence of CO2/HCO3 -, of 6.94 ± 0.1; after an acid load PC-Cl3 cells recovered toward resting pHi value, using a Na-dependent H+ extrusion mechanisms which was amiloride sensitive (Ki = 23 μM). The kinetic parameters were K(Na)app = 10 ± 2 mM and Vmax = 0.23 ± 0.02 ΔpH/min x 105 cells. NHE1, NHE2 and NHE3 were expressed at the mRNA level as well as at the protein level. Conclusion: PC-Cl3 cells express a functional Na/H exchange activity and different isoforms (NHE1, NHE2 and NHE3) are expressed in the plasma membrane. [ABSTRACT FROM AUTHOR]
- Subjects :
- *CELLS
*IODIDES
*AMILORIDE
*MESSENGER RNA
*PROTEINS
*CELL membranes
Subjects
Details
- Language :
- English
- ISSN :
- 10158987
- Volume :
- 13
- Issue :
- 4
- Database :
- Academic Search Index
- Journal :
- Cellular Physiology & Biochemistry (Karger AG)
- Publication Type :
- Academic Journal
- Accession number :
- 20728859
- Full Text :
- https://doi.org/10.1159/000072423