Background: This study explores regional differences in the response to mucosal D-glucose and L-amino acids in both normal intestine and intestine stimulated with cholera toxin.
Methods: Proximal, mid and distal small intestines from 6- to 8-week-old pigs were bathed in Ussing chambers with a buffer containing 15 mM serosal glucose, and the effect of adding a cocktail giving luminal chamber concentrations of 15 mM D-glucose and 20 mM of each L-alanine, L-proline, L-lysine, L-phenylalanine, and L-glutamine on transmucosal Na+ and Cl- transport was measured.
Results: In all segments of both normal and cholera toxin-treated intestine, electrogenic Na+ and electroneutral NaCl absorption were promoted. No significant differences in the net increase of Na+ and Cl- absorption between normal and cholera toxin-stimulated intestine were present. Under both conditions no segmental differences were present in the stimulated Cl- absorption, describing identical capacity for stimulated electroneutral NaCl absorption. In contrast the electrogenic Na+ absorption was, compared to the proximal part, doubled in the mid and distal parts under both conditions.
Conclusions: We conclude that mucosal D-glucose and L-amino acids stimulate electroneutral NaCl and electrogenic Na+ absorption to the same degree in normal and cholera toxin-treated small intestine. There is no segmental difference in stimulated electroneutral NaCl absorption, while electrogenic Na+ absorption is highest in mid and distal parts.