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Titolo:
Polarized expression of different monocarboxylate transporters in rat medullary thick limbs of henle
Autore:
Eladari, D; Chambrey, R; Irinopoulou, T; Leviel, F; Pezy, F; Bruneval, P; Paillard, M; Podevin, RA;
Indirizzi:
Univ Paris 06, INSERM, U356, F-75270 Paris, France Univ Paris 06 Paris France F-75270 , INSERM, U356, F-75270 Paris, France Univ Paris 06, INSERM, U430, F-75270 Paris, France Univ Paris 06 Paris France F-75270 , INSERM, U430, F-75270 Paris, France Hop Broussais, Assistance Publ Hop Paris, F-75270 Paris, France Hop Broussais Paris France F-75270 Publ Hop Paris, F-75270 Paris, France
Titolo Testata:
JOURNAL OF BIOLOGICAL CHEMISTRY
fascicolo: 40, volume: 274, anno: 1999,
pagine: 28420 - 28426
SICI:
0021-9258(19991001)274:40<28420:PEODMT>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
ASCENDING LIMB; APICAL MEMBRANE; PROXIMAL TUBULE; PYRUVATE; LACTATE; CLONING; MCT2; MECHANISMS; SUBSTRATE; NEPHRON;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
24
Recensione:
Indirizzi per estratti:
Indirizzo: Podevin, RA Inst Biomed Cordeliers, 15 Rue Ecole Med, F-75270 Paris 06, France Inst Biomed Cordeliers 15 Rue Ecole Med Paris France 06 rance
Citazione:
D. Eladari et al., "Polarized expression of different monocarboxylate transporters in rat medullary thick limbs of henle", J BIOL CHEM, 274(40), 1999, pp. 28420-28426

Abstract

Extracellular lactic acid is a major fuel for the mammalian medullary thick ascending Limb (MTAL), whereas under anoxic conditions, this nephron segment generates a large amount of lactic acid, which needs to be excreted. Wetherefore evaluated, at both the functional and molecular levels, the possible presence of monocarboxylate transporters in basolateral (BLMVs) and luminal (LMVs) membrane vesicles isolated from rat MTALs. Imposing an inward H+ gradient induced the transient uphill accumulation of L-[C-14]lactate inboth types of vesicles. However, whereas the pH gradient-stimulated uptakeof L-[C-14]lactate in BLMVs was inhibited by anion transport blockers suchas alpha-cyano-4-hydroxycinnamate, 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), and furosemide, it was unaffected by these agents in LMVs, indicating the presence of a L-lactate/H+ cotransporter in BLMVs, but not in LMVs. Under non-pH gradient conditions, however, the uptake of L-[C-14]lactate in LMVs was transstimulated 100% by L-lactate, but by only 30% byD-lactate. Furthermore, this L-lactate self-exchange was markedly inhibited by alpha-cyano-4-hydroxycinnamate and DIDS and almost completely by 1 mM furosemide, findings consistent with the existence of a stereospecific carrier-mediated lactate transport system in LMVs. Using immunofluorescence confocal microscopy and immunoblotting, the monocarboxylate transporter (MCT)-2 isoform was shown to be specifically expressed on the basolateral domain of the rat MTAL, whereas the MCT1 isoform could not be detected in this nephron segment. This study thus demonstrates the presence of different monacarboxylate transporters in rat MTALs; the basolateral H+/L-lactate cotransporter (MCT2) and the luminal H+- independent organic anion exchanger are adapted to play distinct roles in the transport of monocarboxylates in MTALs.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 12/07/20 alle ore 03:26:58