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Ethanol selectively affects Na+-gradient dependent intestinal transport systems.

B O'Neill·F Weber·D Hornig·G Semenza
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Abstract

Moderate concentrations of ethanol reduce the velocity of uptake of three representative Na+-symport systems (D-glucose, L-alanine, L-ascorbate), whether electrogenic (the first two) or electroneutral (L-ascorbate). This 'inhibition' is observed only if these transport systems are tested in the presence of an initial Na+ gradient (out greater than in); no inhibition is found in tracer-equilibrium exchange measurements. A representative Na+-independent system (D-fructose) is not inhibited by ethanol. 'Passive diffusion' (measured as uptake of L-glucose) is increased somewhat by alcohol. All these observations can be rationalized [as suggested by Tillotson et al. (1981) Arch. Biochem. Biophys. 207, 360-370] by an effect of ethanol on passive diffusion, which leads to a faster collapse of the Na+ gradient, with the resulting reduction of the uptake velocities of Na+-dependent transport systems when tested with the added driving force of an Na+ out----in gradient.

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AlanineAnimalsAscorbic AcidBiological Transport, ActiveDiffusionEthanolFructoseGlucoseGuinea PigsIn Vitro TechniquesIntestinal AbsorptionIntestinal MucosaIntestine, SmallMicrovilliSodiumJournal Article

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BibTeXRIS

B O'Neill, F Weber, D Hornig, G Semenza. 1986-01-01. Ethanol selectively affects Na+-gradient dependent intestinal transport systems.. https://doi.org/10.1016/0014-5793(86)80073-4

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