title: Intestinal transport of tryptophan and its analogs.
abstract: A comparative study of the intestinal transport of DL-tryptophan and its 1-methylindole (tryptophan-l-Me) and benzo[b]thiophene (tryptophan-S) analogs has been carried out in vitro, using the everted intestinal sac of the rat and hamster. Both tryptophan and tryptophan-S are actively transported across the intestine, while tryptophan-l-Me is not actively transported. The active transport of tryptophan is competitively inhibited by tryptophan-S, suggesting a similar carrier, while tryptophan-l-Me is not an inhibitor of tryptophan transport, suggesting little or no interaction with the carrier. The transport of tryptophan and tryptophan-S is depressed at concentrations (10 mM), and all three amino acids produce subtle alterations in the barrier properties of the sacs, as evidenced by increased tetraethylammonium bromide-14C diffusion.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D001693:Biological Transport, Active; D006224:Cricetinae; D004058:Diffusion; D007413:Intestinal Mucosa / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051381:Rats; D013757:Tetraethylammonium Compounds / Q000378:metabolism; D014364:Tryptophan / Q000031:analogs & derivatives / Q000378:metabolism*
chemical_list: D013757:Tetraethylammonium Compounds; D014364:Tryptophan