In:
American Journal of Physiology-Gastrointestinal and Liver Physiology, American Physiological Society, Vol. 276, No. 3 ( 1999-03-01), p. G789-G794
Abstract:
Traditionally, intestinal glucose absorption was thought to occur through active, carrier-mediated transport. However, proponents of paracellular transport have argued that previous experiments neglected effects of solvent drag coming from high local concentrations of glucose at the brush-border membrane. The purpose of this study was to evaluate glucose absorption in the awake dog under conditions that would maximize any contribution of paracellular transport. Jejunal Thiry-Vella loops were constructed in six female mongrel dogs. After surgical recovery, isotonic buffers containingl-glucose as the probe for paracellular permeability were given over 2-h periods by constant infusion pump. At physiological concentrations ofd-glucose (1–50 mM), the fractional absorption ofl-glucose was only 4–7% of total glucose absorption. Infusion of supraphysiological concentrations (150 mM) of d-glucose,d-maltose, ord-mannitol yielded low-fractional absorptions ofl-glucose (2–5%), so too did complex or nonabsorbable carbohydrates. In all experiments, there was significant fractional water absorption (5–19%), a prerequisite for solvent drag. Therefore, with even up to high concentrations of luminal carbohydrates in the presence of significant water absorption, the relative contribution of paracellular glucose absorption remained low.
Type of Medium:
Online Resource
ISSN:
0193-1857
,
1522-1547
DOI:
10.1152/ajpgi.1999.276.3.G789
Language:
English
Publisher:
American Physiological Society
Publication Date:
1999
detail.hit.zdb_id:
1477329-6
SSG:
12
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