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This Article Full Text Full Text (PDF) All Versions of this Article: 295/5/F1342    most recent 00048.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Leite-Dellova, D. C. A. Articles by Mello-Aires, M. Search for Related Content PubMed PubMed Citation Articles by Leite-Dellova, D. C. A. Articles by Mello-Aires, M.

Genomic and nongenomic dose-dependent biphasic effect of aldosterone on Na⁺/H⁺ exchanger in proximal S3 segment: role of cytosolic calcium

Department of Physiology and Biophysics, Instituto de Ciências Biomédicas, University of São Paulo, São Paulo, Brazil

Submitted 28 January 2008 ; accepted in final form 15 August 2008

The effects of aldosterone on the intracellular pH recovery rate (pHirr) via Na⁺/H⁺ exchanger and on the [Ca²⁺]_i were investigated in isolated rat S3 segment. Aldosterone [10^–12, 10^–10, or 10^–8 M with 1-h, 15- or 2-min preincubation (pi)] caused a dose-dependent increase in the pHirr, but aldosterone (10^–6 M with 1-h, 15- or 2-min pi) decreased it (these effects were prevented by HOE694 but not by S3226). After 1 min of aldosterone pi, there was a transient and dose-dependent increase of the [Ca²⁺]_i and after 6-min pi there was a new increase of [Ca²⁺]_i that persisted after 1 h. Spironolactone, actinomycin D, or cycloheximide did not affect the effects of aldosterone (15- or 2-min pi) but inhibited the effects of aldosterone (1-h pi) on pHirr and on [Ca²⁺]_i. RU 486 prevented the stimulatory effect of aldosterone (10^–12 M, 15- or 2-min pi) on both parameters and maintained the inhibitory effect of aldosterone (10^–6 M, 15- or 2-min pi) on the pHirr but reversed its stimulatory effect on the [Ca²⁺]_i to an inhibitory effect. The data indicate a genomic (1 h, via MR) and a nongenomic action (15 or 2 min, probably via GR) on [Ca²⁺]_i and on the basolateral NHE1 and are compatible with stimulation of the NHE1 by increases in [Ca²⁺]_i in the lower range (at 10^–12 M aldosterone) and inhibition by increases at high levels (at 10^–6 M aldosterone) or decreases in [Ca²⁺]_i (at 10^–6 M aldosterone plus RU 486).

mineralocorticoid stimulatory/inhibitory action; NHE1; proximal tubule; intracellular pH; intracellular Ca²⁺

This article has been cited by other articles:

				P. S. Pergher, D. Leite-Dellova, and M. de Mello-Aires Direct action of aldosterone on bicarbonate reabsorption in in vivo cortical proximal tubule Am J Physiol Renal Physiol, May 1, 2009; 296(5): F1185 - F1193. [Abstract] [Full Text] [PDF]