Two endogenous methyl-alpha-D-glucopyranoside uptake activities in Xenopus oocytes.
Endogenous methyl-alpha-D-glucopyranoside (AMG) uptake in Xenopus oocytes was measured with 14C-labeled AMG. Two AMG uptake activities, one Na(+)-dependent and the other Na(+)-independent, were observed in oocytes incubated with 2 mM AMG. However, only Na(+)-dependent uptake was observed at 0.1 mM AMG. Na(+)-dependent AMG uptake was attributed to the endogenous Na+/glucose co-transporter since it was inhibited by phlorizin. On the other hand, Na(+)-independent AMG uptake was inhibited by cytochalasin B or 2-deoxy-D-glucose. This suggests that AMG can be transported by the endogenous facilitated glucose transporter as well as by the endogenous co-transporter. In addition, a substrate range of the endogenous co-transporter was examined by competition experiments.
Nagata
K
K
Department of Physiology, Faculty of Medicine, Tottori University, Yonago, Japan.
Ichikawa
O
O
D000818:Animals; D001667:Binding, Competitive; D003571:Cytochalasin B / Q000494:pharmacology; D003847:Deoxyglucose / Q000494:pharmacology; D008757:Methylglucosides / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism*; D012964:Sodium / Q000502:physiology; D014982:Xenopus laevis / Q000033:anatomy & histology / Q000378:metabolism*
D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D003571:Cytochalasin B; C027020:methylglucoside; D003847:Deoxyglucose; D012964:Sodium