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Proton-lactate cotransport in basolateral membrane vesicles from rat jejunum
M N Orsenigo1, M Tosco, U Laforenza
1Dipartimento di Fisiologia e Biochimica Generali, Università di Milano, Italy.
Bioscience Reports
|December 1, 1996
Summary
This study shows proton-coupled lactate transport in rat jejunal enterocytes. An inward proton gradient drives L-lactate uptake, suggesting a symport mechanism.
Area of Science:
- Physiology
- Biochemistry
- Molecular Biology
Background:
- Lactate transport is crucial for cellular energy metabolism.
- Understanding proton-coupled lactate transport in the jejunum is important for nutrient absorption.
Purpose of the Study:
- To investigate the mechanism of L-lactate transport across the basolateral membrane of rat jejunal enterocytes.
- To determine the role of proton gradients in this transport process.
Main Methods:
- Purified rat jejunal enterocyte membrane vesicles were used.
- L-lactate uptake was measured under various conditions, including different pH gradients and in the presence of inhibitors.
Main Results:
- L-lactate uptake was stimulated by an inwardly directed H+ gradient.
- This stimulation was reduced by FCCP and pCMBS, and inhibited by unlabeled L-lactate and SCN-.
- Furosemide had no effect on L-lactate uptake.
Conclusions:
- The results strongly suggest a proton-lactate symport mechanism at the basolateral membrane of rat jejunal enterocytes.
- This finding helps explain previously conflicting reports on H(+)-lactate symport in this tissue.