Effect of amino acids on sugar absorption.
1. Sacs of everted mid-small intestine of the hamster have been used to study the effect of amino acids on sugar absorption.2. The sugars employed were D-glucose, D-galactose, 3-O-methyl-D-glucose, D-fucose, L-glucose, alpha-glucoheptose, L-fucose, D-mannose and L-sorbose. The amino acids were L- and D-histidine, L- and D-methionine, L- and D-alanine, L- and D-valine, L- and D-glutamic acid, L-leucine, L-proline, L-ornithine and L-aspartic acid.3. Actively absorbed amino acids considerably inhibit the transport of actively absorbed sugars. The results give support for the view that D-histidine and L-glucose are actively transferred. Passively absorbed amino acids and sugars are not involved.4. As L-glutamic and L-aspartic acids in the mucosal fluid have no inhibitory effect on D-glucose absorption, although mucosal fluid L-alanine is quite potent, the step at which the latter exerts its inhibitory action must be before that at which the intracellular transamination of L-glutamic and L-aspartic acids occurs. It would seem likely, therefore, that L-alanine interferes with the process by which epithelial cells capture and concentrate sugars at the luminal border.5. More than one active transfer system may exist for D-glucose.6. The influence of actively absorbed L-amino acids on D-glucose active transport seems to be in some way related to the efficiency with which the amino acids are themselves concentrated.7. Inhibition of D-glucose active absorption by an amino acid may be a simple test of an amino acid's participation in an active transport system.
D000409:Alanine / Q000494:pharmacology; D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects*; D006224:Cricetinae; D005971:Glutamates / Q000494:pharmacology; D006601:Hexoses / Q000378:metabolism*; D006639:Histidine / Q000494:pharmacology; D007408:Intestinal Absorption / Q000187:drug effects*; D009952:Ornithine / Q000494:pharmacology; D011392:Proline / Q000494:pharmacology; D014633:Valine / Q000494:pharmacology
D000596:Amino Acids; D005971:Glutamates; D006601:Hexoses; D006639:Histidine; D011392:Proline; D009952:Ornithine; D014633:Valine; D000409:Alanine