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Titolo:
Coordinated down-regulation of NBC-1 and NHE-3 in sodium and bicarbonate loading
Autore:
Amlal, H; Chen, Q; Greeley, T; Pavelic, L; Soleimani, M;
Indirizzi:
Univ Cincinnati, Med Ctr, Dept Med, Cincinnati, OH 45267 USA Univ Cincinnati Cincinnati OH USA 45267 ept Med, 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: 5, volume: 60, anno: 2001,
pagine: 1824 - 1836
SICI:
0085-2538(200111)60:5<1824:CDONAN>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
NA+-H+ EXCHANGE; RENAL NA-HCO3 COTRANSPORTER; PROXIMAL CONVOLUTED TUBULE; METABOLIC-ACIDOSIS; MEMBRANE-VESICLES; NA+HCO3 COTRANSPORTER; NA+/HCO3 COTRANSPORTER; PARATHYROID-HORMONE; MOLECULAR ASPECTS; DISEASE PROCESSES;
Keywords:
acid-base transporters; metabolic alkalosis; renoprotection; transporters; basolateral membrane; kidney proximal tubule;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Soleimani, M Univ Cincinnati, Med Ctr, Dept Med, 231 Albert Sabin Way,MSB 5502, Cincinnati, OH 45267 USA Univ Cincinnati 231 Albert Sabin Way,MSB 5502 Cincinnati OH USA 45267
Citazione:
H. Amlal et al., "Coordinated down-regulation of NBC-1 and NHE-3 in sodium and bicarbonate loading", KIDNEY INT, 60(5), 2001, pp. 1824-1836

Abstract

Background. Bicarbonate reabsorption in the kidney proximal tubule is predominantly mediated via the apical Na+/H+ exchanger (NHE-3) and basolateral Na+:HCO3- cotransporter (NBC-1). The purpose of these studies was to examine the effects of Na+ load and altered acid-base status on the expression ofNHE-3 and NBC-1 in the kidney. Methods. Rats were placed on 280 mmol/L of NaHCO3, NaCl, or NH4Cl added totheir drinking water for 5 days and examined for the expression of NHE-3 and NBC-1 in the kidney. Results. Serum [HCO3-] was unchanged in NaHCO3- and NaCl-loaded animals versus control (P>0.05). However, a significant hyperchloremic metabolic acidosis was developed in NH4Cl-loaded animals. A specific polyclonal antibody against NBC-1 recognized a 130 kD band, which was exclusively expressed in the basolateral membrane of proximal tubules. Immunoblot studies indicated that the protein abundance of NBC-1 and NHE-3 in the cortex decreased by 74% (P<0.04) and 66% (P<0.03), respectively, in NaHCO3 loading and by 72% (P<0.003) and 55% (P<0.04), respectively, in NaCl loading. Switching from NaHCO3 to distilled water resulted in rapid recovery of NHE-3 and NBC-1 proteinexpression toward normal levels. Metabolic acidosis increased the abundance of NHE-3 (P<0.0001) but not NBC-1 (P>0.05). Conclusions. NaHCO3- or NaCl loading coordinately downregulates the apicalNHE-3 and basolateral NBC-1 in rat kidney proximal tubule, presumably due to increased Na+ load. We propose that the down-regulation of these two Na+- and HCO3-absorbing transporters is, to a large degree, responsible for enhanced excretion of excess of Na+ and alkaline load and prevention of metabolic alkalosis in rats subjected to NaHCO3- loading.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/01/20 alle ore 15:19:45