title: alpha-Methylglucoside satisfies only Na+-dependent transport system of intestinal epithelium.
abstract: The unidirectional influx of alpha-methylglucoside (alpha-MG) by isolated chicken intestinal epithelial cells is 98% inhibited by phlorizin. The remaining 2% of the total influx occurs in the absence of Na+, is not sensitive to phloretin, and is equal to the diffusional entry rate for 2-deoxyglucose. The glucoside is much more strongly accumulated (75-fold) than 3-O-methylglucose (3-OMG) (10-fold). Inhibitors of the serosal sugar carrier (phloretin, cytochalasin B, theophylline, and flavanoids) do not enhance alpha-MG accumulation. It is concluded that the glycoside is not a substrate for the intestinal serosal transport system. Steady-state gradients of the sugar can be represented accurately by a concentrative, phlorizin-sensitive system that is opposed by a diffusional efflux process.
mesh_terms: D019325:3-O-Methylglucose; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002645:Chickens; D003847:Deoxyglucose / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007700:Kinetics; D008757:Methylglucosides / Q000378:metabolism*; D008759:Methylglycosides / Q000378:metabolism*; D010695:Phlorhizin / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology*
chemical_list: D008757:Methylglucosides; D008759:Methylglycosides; D019325:3-O-Methylglucose; C027020:methylglucoside; D000255:Adenosine Triphosphate; D003847:Deoxyglucose; D012964:Sodium; D010695:Phlorhizin