We investigated the existence of an endogenous system for lactate transport in Xenopus laevis oocytes. Cl-36-uptake studies excluded the involvement of a DIDS-sensitive anion antiporter as a possible pathway for lactate movement. L-[C-14]lactate uptake was unaffected by superimposed pH gradients, stimulated by the presence of Na+ in the incubating solution, and severely reduced by the monocarboxylate transporter inhibitor p-chloromercuribenzenesulphonate (pCMBS). Transport exhibited a broad cation specificity and was cis inhibited by other monocarboxylates, mostly by pyruvate. These results suggest that lactate uptake is mediated mainly by a transporter and that the preferred anion is pyruvate. [C-14]pyruvate uptake exhibited the same pattern of functional properties evidenced for L-lactate. Kinetic parameters were calculated for both monocarboxylates, and a higher affinity for pyruvate was revealed. Various inhibitors of monocarboxylate transporters reduced significantly pyruvate uptake. These studies demonstrate that Xenopus laevis oocytes possess a monocarboxylate transport system that shares some functional features with the members of the mammalian monocarboxylate cotransporters family, but, in the meanwhile, exhibits some particular properties, mainly concerning cation specificity.
An endogenous monocarboxylate transport in Xenopus laevis oocytes / M. Tosco, M.N. Orsenigo, G. Gastaldi, A. Faelli. - In: AMERICAN JOURNAL OF PHYSIOLOGY. REGULATORY, INTEGRATIVE AND COMPARATIVE PHYSIOLOGY. - ISSN 0363-6119. - 278:5(2000), pp. R1190-R1195.
|Titolo:||An endogenous monocarboxylate transport in Xenopus laevis oocytes|
TOSCO, MARISA GIUSEPPINA DOROTEA (Primo)
ORSENIGO, MARIA NOVELLA (Secondo)
FAELLI, ALIDE (Ultimo)
|Parole Chiave:||Lactate transport; Pyruvate transport; Xenopus oocytes|
|Settore Scientifico Disciplinare:||Settore BIO/09 - Fisiologia|
|Data di pubblicazione:||2000|
|Appare nelle tipologie:||01 - Articolo su periodico|