Changes in D-glucose uptake by brush-border vesicles from small intestine of rats treated with mitomycin C

The effect of mitomycin C pre-administration on the D-glucose transport system in the intestinal brush-border membrane of rat small intestine was examined by a rapid filtration technique. Forty-eight hours following the intravenous administration of mitomycin C, there were extensive and severe mucosal derangements. At this time point, membrane vesicles were prepared from the mitomycin-C-pretreated and control rats. Binding studies indicated that D-glucose entered into the intravesicular space of vesicles even in the case of mitomycin-C-pretreated rats. Vesicles obtained from both the mitomycin-C-pretreated and the control rats showed sodium-dependent uptake of D-glucose, but the initial uptake at 15 sec was significantly greater in control rats than in mitomycin-C-pretreated rats. Comparison of kinetic parameters of D-glucose transport indicated that Km was not significantly different between control and mitomycin-C pretreated rats. The pretreatment with mitomycin C decreased Vmax and increased the diffusional permeability to D-glucose considerably. These changes induced by mitomycin C seemed to derive not from a direct effect on mature enterocytes but from an indirect effect secondary to mitotic inhibition in the crypts.