Absorption of N4-D-glucopyranosylsulphamethazine by rat everted intestinal sacs.

Absorption of the N4-D-glucose conjugate of sulphamethazine (glucose-SMZ, 0.5 mM) by isolated everted sacs of the rat small intestine was studied at 37 degrees and pH 6.6. Phlorizin (0.5-2.0 mM) significantly reduced (P < 0.05) both mucosal and serosal transfer of glucose-SMZ and inhibition of mucosal transfer appeared to be concentration-dependent. Phloretin (0.5 mM) and removal of Na+ from the incubation medium also diminished absorption of glucose-SMZ. Furthermore, D-glucose (0.5 and 5.0 mM) inhibited mucosal and serosal transfer of the glycoside. The results suggest the D-glucose/Na+ cotransporter mediates absorption of glucose-SMZ from the small intestine of the rat. Thus, glucose-SMZ might be bioavailable from ingested tissues in which it is present.