Interactions between monosaccharides and leucine in basolateral membrane of isolated chick intestinal epithelial cells.
The characteristics of the interactions between 3-O-methyl-glucose (3-OMG) and monosaccharides or leucine transport were examined on chick isolated intestinal epithelial cells. In a Na+-medium, the unidirectional influx of 1.5 mM 3-OMG was found to be already inhibited by 37.5 mM glucose and 37.5 mM leucine after 20 s incubation. In Na+-free mannitol substituted medium, either glucose, galactose or leucine (37.5 mM) inhibited the unidirectional influx of 3-OMG. Theophylline, a drug that decreases the basolateral permeability to sugars, decreased the unidirectional influx of 1.25 mM leucine in Na+-free medium but increased the steady-state uptake of the aminoacid in Na+-medium. The efflux of 3-OMG from preloaded cells into a Na+-free medium was stimulated by extracellular galactose and leucine (37.5 mM). This was inhibited by theophylline. Our results indicate that sugars and leucine interactions at the Na+-independent transport system could be produced by mutual competition for binding the same system.
D019325:3-O-Methylglucose; D000818:Animals; D001485:Basement Membrane / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002645:Chickens; D004848:Epithelium / Q000378:metabolism; D007408:Intestinal Absorption / Q000187:drug effects; D007413:Intestinal Mucosa / Q000378:metabolism*; D007930:Leucine / Q000378:metabolism*; D008297:Male; D008757:Methylglucosides / Q000378:metabolism; D009005:Monosaccharides / Q000378:metabolism*; D013806:Theophylline / Q000494:pharmacology
D008757:Methylglucosides; D009005:Monosaccharides; D019325:3-O-Methylglucose; D013806:Theophylline; D007930:Leucine