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Titolo:
Glucocorticoids enhance the expression of the basolateral Na+: HCO3- cotransporter in renal proximal tubules
Autore:
Ali, R; Amlal, H; Burnham, CE; Soleimani, M;
Indirizzi:
Univ Cincinnati, Dept Internal Med, Div Nephrol & Hypertens, Cincinnati, OH 45267 USA Univ Cincinnati Cincinnati OH USA 45267 pertens, Cincinnati, OH 45267 USA Vet Affairs Med Ctr, Cincinnati, OH 45267 USA Vet Affairs Med Ctr Cincinnati OH USA 45267 Ctr, Cincinnati, OH 45267 USA
Titolo Testata:
KIDNEY INTERNATIONAL
fascicolo: 3, volume: 57, anno: 2000,
pagine: 1063 - 1071
SICI:
0085-2538(200003)57:3<1063:GETEOT>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
NA+-H+ EXCHANGE; BORDER MEMBRANE-VESICLES; METABOLIC-ACIDOSIS; RAT-KIDNEY; ANTIPORTER; TRANSPORT; ADAPTATION; ALKALOSIS; CLONING; BINDING;
Keywords:
acid-base; glucocorticoids; HCO3- reabsorption; transporters; Na+/H+ antiporter;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Soleimani, M Univ Cincinnati, Dept Internal Med, Div Nephrol & Hypertens, 231 Bethesda Ave,MSB 5502, Cincinnati, OH 45267 USA Univ Cincinnati 231 Bethesda Ave,MSB 5502 Cincinnati OH USA 45267
Citazione:
R. Ali et al., "Glucocorticoids enhance the expression of the basolateral Na+: HCO3- cotransporter in renal proximal tubules", KIDNEY INT, 57(3), 2000, pp. 1063-1071

Abstract

Background, Studies have shown that glucocorticoids enhance HCO3- reabsorption in proximal tubules. Functional and molecular studies indicate that HCO3- reabsorption in proximal tubules is mediated via luminal H+-ATPase and Na+/H+ exchanger (NHE-3), and basolateral Na+:HCO3- co-transporter (NBC) acting in series. The purpose of these experiments was to examine the effect of adrenal steroids on NBC-1 and NHE-3 expression and activity in rat renalproximal tubules. Methods. Rats were injected subcutaneously with dexamethasone (100 mu/day)or deoxycorticosterone acetate (30 mg/kg), potent glucocorticoid, or mineralocorticoid analogues, respectively. Animals were sacrificed after two or four days, and NBC-1 and NHE-3 mRNA expression and activities were measuredin cortex and proximal tubules. Results. Northern hybridizations indicated that cortical NBC-1 mRNA expression increased by approximately 92% in rats treated with dexamethasone for four days (N = 6, P < 0.03) but not two days. NHE-3 mRNA expression remained unchanged. NBC and NHE-3 activities were measured as the Na-dependent pH(i) recovery from an acid load in the presence or absence of HCO3-, respectively, and appropriate inhibitors in proximal tubule suspensions loaded withBCECF. NBC activity increased by approximately 80% in rats treated with dexamethasone for four days (P < 0.01, N = 5) but not two days. NHE-3 activity increased by 34 and 42% in rats treated with dexamethasone for two and four days, respectively (P < 0.05 and P < 0.02 for each group vs, control). Treatment with deoxycorticosterone acetate did not alter NBC-1 expression. Conclusion. Glucocorticoids at pharmacologic concentrations enhance the mRNA expression and functional activity of renal proximal tubule NBC-1. Enhanced NBC and NHE-3 activities could result in increased HCO3- reabsorption in proximal tubule and could contribute to the maintenance of metabolic alkalosis in pathophysiologic states associated with increased glucocorticoid production.

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Documento generato il 06/04/20 alle ore 04:55:59