In vivo sugar diffusion in the ileal epithelium of spontaneously hypertensive rats.
BACKGROUND
D-glucose absorption, distinguishing between active and diffusive components, was studied in the ileum of spontaneously hypertensive rats (SHR) and their normotensive control Wistar-Kyoto (WKY) rats. Net water transport was also determined.


METHODS
A perfusion system in vivo with ileum loops was used, and experiments with phlorizin, phloretin and 2,4,6-triaminopyrimidine (TAP) were performed in order to discriminate between active and diffusive components and between transcellular and paracellular routes.


RESULTS
A significant decrease in total D-glucose absorption was found in SHR compared to WKY rats, this reduction being due to a lower SGLT1-mediated component. The effect was not compensated by the total diffusive component, since the phlorizin-insensitive D-glucose absorption did not significantly change between rat strains. However, the diffusive component of D-glucose transport was relatively more important in hypertensive than in normotensive rats. The use of 2,4,6-triaminopyrimidine (TAP), which blocks the transport across the paracellular route, showed that the paracellular diffusion of D-glucose was higher in SHR than in WKY rats. Intestinal net water absorption was not modified between either group of animals, though the presence of phlorizin in the perfusate decreased the ileal water absorption to a greater extent in normotensive rats.


CONCLUSIONS
The observed reduction in D-glucose absorption in vivo in the ileum of SHR was due to a decrease in the SGLT1-active component. Despite the paracellular diffusion of D-glucose being higher in hypertensive than in normotensive rats, the total diffusion component was not high enough to compensate this alteration.
Mate
A
A
Dept. of Physiology and Zoology, University of Seville, c/Tramontana s/n, Seville, Spain.
Gómez-Amores
L
L
Vázquez
C M
CM
Bolufer
J
J
D000818:Animals; D001692:Biological Transport; D004058:Diffusion; D005947:Glucose / Q000378:metabolism*; D006973:Hypertension / Q000378:metabolism*; D007082:Ileum / Q000378:metabolism*; D007408:Intestinal Absorption / Q000502:physiology; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D010695:Phlorhizin / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D014867:Water / Q000378:metabolism
D014867:Water; D010695:Phlorhizin; D005947:Glucose