title: The transport of glutamine and alanine into rat colonocytes.
abstract: The transport of glutamine and alanine into isolated rat colonocytes was studied. The transport of both amino acids appears to be dependent on a Na+ gradient. The apparent Km values for the transport of glutamine and alanine were 2.56 +/- 0.84 and 5.35 +/- 1.20 mM respectively, but with similar Vmax. values. Glutamine and alanine transport were mutually competitive, and the transport of both amino acids was competitively inhibited by 2-methylaminoisobutyrate. In contrast, histidine inhibited the transport of both glutamine and alanine non-competitively. It is concluded that glutamine and alanine are transported into rat colonocytes by a common carrier system similar to System A of other cells. It is suggested that the metabolic function of this transport system in rat colonocytes might be the partial exchange of extracellular glutamine for intracellular alanine.
mesh_terms: D000409:Alanine / Q000378:metabolism*; D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D003106:Colon / Q000378:metabolism*; D004734:Energy Metabolism; D005973:Glutamine / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D005973:Glutamine; D012964:Sodium; D000409:Alanine