The mechanisms of brush border Na+/H+ exchanger activation by corticosteroids
Background: Previously we showed that corticosterone and aldosterone increased proton fluxes in proximal tubule, by micropuncture and stationary microperfusion. Since the Na+/H+ exchanger is responsible for the main proximal proton secretion, we have now evaluated the effects aldosterone on Na+/H+ e...
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2003
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_12341010_v9_n2_pBR85_Zallocchi http://hdl.handle.net/20.500.12110/paper_12341010_v9_n2_pBR85_Zallocchi |
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paper:paper_12341010_v9_n2_pBR85_Zallocchi2023-06-08T16:10:11Z The mechanisms of brush border Na+/H+ exchanger activation by corticosteroids Zallocchi, Marisa Laura Calvo, Juan Carlos Aldosterone Glucocorticoids H+ transport NHE2 NHE3 acridine orange aldosterone corticosteroid corticosterone gluconate sodium mineralocorticoid sodium proton exchange protein article brush border fluorometry kidney proximal tubule molecular dynamics molecular mechanics proton transport receptor affinity transport kinetics upregulation Western blotting Adrenalectomy Aldosterone Animals Anti-Inflammatory Agents Corticosterone Gluconates Kidney Tubules, Proximal Male Microvilli Protein Isoforms Rats Rats, Sprague-Dawley Sodium-Hydrogen Antiporter Background: Previously we showed that corticosterone and aldosterone increased proton fluxes in proximal tubule, by micropuncture and stationary microperfusion. Since the Na+/H+ exchanger is responsible for the main proximal proton secretion, we have now evaluated the effects aldosterone on Na+/H+ exchange activity in brush border vesicles. In order to evaluate the mechanism of action of glucocorticoids and mineralocorticoids, we studied the comparative effects of corticosterone and aldosterone on the abundance of NHE3 and NHE2 isoforms. Material/Methods: We isolated renal brush border vesicles from rats by differential centrifugation in sham-operated, adrenalectomized, and adrenalectomized-aldosterone treated (ADX + aldosterone) animals. We measured the kinetics of H+ transport in response to increasing concentrations of Sodium Gluconate by fluorimetry using acridine orange. For Na+/H+ exchanger abundance we used Western blot analysis of brush border proteins in the above groups and in adrenalectomized-corticosterone treated rats. Results: The Vmax in adrenalectomized animals was 22,162±1828 fluorescence units/min; in sham animals, 37,020±2722; and in ADX + aldosterone, 42,344±3044 (p<0.01 adrenalectomized vs others). No differences in Km were observed. Adrenalectomy decreased NHE3 abundance over Sham by 32% without modifying NHE2. Corticosterone-replacement enhanced NHE3 abundance by 76% and failed to increase NHE2. Aldosterone enhanced NHE2 abundance by 75% and did not increase NHE3. Conclusion: Mineralocorticoids enhance Na+/H+ exchange activity by increasing NHE2 abundance; glucocorticoids, by increasing NHE3 abundance. Fil:Zallocchi, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Calvo, J.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2003 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_12341010_v9_n2_pBR85_Zallocchi http://hdl.handle.net/20.500.12110/paper_12341010_v9_n2_pBR85_Zallocchi |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Aldosterone Glucocorticoids H+ transport NHE2 NHE3 acridine orange aldosterone corticosteroid corticosterone gluconate sodium mineralocorticoid sodium proton exchange protein article brush border fluorometry kidney proximal tubule molecular dynamics molecular mechanics proton transport receptor affinity transport kinetics upregulation Western blotting Adrenalectomy Aldosterone Animals Anti-Inflammatory Agents Corticosterone Gluconates Kidney Tubules, Proximal Male Microvilli Protein Isoforms Rats Rats, Sprague-Dawley Sodium-Hydrogen Antiporter |
| spellingShingle |
Aldosterone Glucocorticoids H+ transport NHE2 NHE3 acridine orange aldosterone corticosteroid corticosterone gluconate sodium mineralocorticoid sodium proton exchange protein article brush border fluorometry kidney proximal tubule molecular dynamics molecular mechanics proton transport receptor affinity transport kinetics upregulation Western blotting Adrenalectomy Aldosterone Animals Anti-Inflammatory Agents Corticosterone Gluconates Kidney Tubules, Proximal Male Microvilli Protein Isoforms Rats Rats, Sprague-Dawley Sodium-Hydrogen Antiporter Zallocchi, Marisa Laura Calvo, Juan Carlos The mechanisms of brush border Na+/H+ exchanger activation by corticosteroids |
| topic_facet |
Aldosterone Glucocorticoids H+ transport NHE2 NHE3 acridine orange aldosterone corticosteroid corticosterone gluconate sodium mineralocorticoid sodium proton exchange protein article brush border fluorometry kidney proximal tubule molecular dynamics molecular mechanics proton transport receptor affinity transport kinetics upregulation Western blotting Adrenalectomy Aldosterone Animals Anti-Inflammatory Agents Corticosterone Gluconates Kidney Tubules, Proximal Male Microvilli Protein Isoforms Rats Rats, Sprague-Dawley Sodium-Hydrogen Antiporter |
| description |
Background: Previously we showed that corticosterone and aldosterone increased proton fluxes in proximal tubule, by micropuncture and stationary microperfusion. Since the Na+/H+ exchanger is responsible for the main proximal proton secretion, we have now evaluated the effects aldosterone on Na+/H+ exchange activity in brush border vesicles. In order to evaluate the mechanism of action of glucocorticoids and mineralocorticoids, we studied the comparative effects of corticosterone and aldosterone on the abundance of NHE3 and NHE2 isoforms. Material/Methods: We isolated renal brush border vesicles from rats by differential centrifugation in sham-operated, adrenalectomized, and adrenalectomized-aldosterone treated (ADX + aldosterone) animals. We measured the kinetics of H+ transport in response to increasing concentrations of Sodium Gluconate by fluorimetry using acridine orange. For Na+/H+ exchanger abundance we used Western blot analysis of brush border proteins in the above groups and in adrenalectomized-corticosterone treated rats. Results: The Vmax in adrenalectomized animals was 22,162±1828 fluorescence units/min; in sham animals, 37,020±2722; and in ADX + aldosterone, 42,344±3044 (p<0.01 adrenalectomized vs others). No differences in Km were observed. Adrenalectomy decreased NHE3 abundance over Sham by 32% without modifying NHE2. Corticosterone-replacement enhanced NHE3 abundance by 76% and failed to increase NHE2. Aldosterone enhanced NHE2 abundance by 75% and did not increase NHE3. Conclusion: Mineralocorticoids enhance Na+/H+ exchange activity by increasing NHE2 abundance; glucocorticoids, by increasing NHE3 abundance. |
| author |
Zallocchi, Marisa Laura Calvo, Juan Carlos |
| author_facet |
Zallocchi, Marisa Laura Calvo, Juan Carlos |
| author_sort |
Zallocchi, Marisa Laura |
| title |
The mechanisms of brush border Na+/H+ exchanger activation by corticosteroids |
| title_short |
The mechanisms of brush border Na+/H+ exchanger activation by corticosteroids |
| title_full |
The mechanisms of brush border Na+/H+ exchanger activation by corticosteroids |
| title_fullStr |
The mechanisms of brush border Na+/H+ exchanger activation by corticosteroids |
| title_full_unstemmed |
The mechanisms of brush border Na+/H+ exchanger activation by corticosteroids |
| title_sort |
mechanisms of brush border na+/h+ exchanger activation by corticosteroids |
| publishDate |
2003 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_12341010_v9_n2_pBR85_Zallocchi http://hdl.handle.net/20.500.12110/paper_12341010_v9_n2_pBR85_Zallocchi |
| work_keys_str_mv |
AT zallocchimarisalaura themechanismsofbrushbordernahexchangeractivationbycorticosteroids AT calvojuancarlos themechanismsofbrushbordernahexchangeractivationbycorticosteroids AT zallocchimarisalaura mechanismsofbrushbordernahexchangeractivationbycorticosteroids AT calvojuancarlos mechanismsofbrushbordernahexchangeractivationbycorticosteroids |
| _version_ |
1768545523325730816 |