PROTON-LACTATE COTRANSPORT IN BASOLATERAL MEMBRANE-VESICLES FROM RAT JEJUNUM

Proton-coupled lactate transport across the basolateral membrane of ra t jejunal enterocyte was studied using well purified membrane vesicles . L-lactate uptake is stimulated by an inwardly directed H+ gradient; the effect of the pH difference is drastically reduced by FCCP and by pCMBS; unlabelled L-lactate causes a strong inhibition, whilst furosem ide is uneffective. The H+ gradient-dependent stimulation of L-lactate uptake is significantly inhibited also by SCN-: this finding could ex plain results recently reported in the literature in which H+-lactate symport was not evidenced in basolateral membranes from rat jejunum.