Transfer of alanine isomers by rat small intestine.
1. A study was made of the transfer of L-alanine, D-alanine and beta-alanine by sacs of everted small intestine of the rat.2. D-Alanine and beta-alanine are transported against a concentration gradient and in this respect resemble L-alanine.3. Transfer of all three isomers was stimulated in presence of glucose, but stimulation was much greater with D-alanine and beta-alanine.4. Transfer of all three isomers was inhibited by galactose.5. The effect of hexoses on amino acid transfer was relatively independent of the effect on fluid transfer.6. L-Methionine inhibited transfer of the three isomers in descending order, L-alanine, D-alanine and beta-alanine, while the magnitude of sarcosine inhibition was in the reverse order.7. At the concentration used (1 mM), L-alanine was transferred mostly by the methionine carrier, and beta-alanine mostly by the sarcosine carrier. D-Alanine occupied an intermediate position.
D000409:Alanine / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects*; D005690:Galactose / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006601:Hexoses / Q000494:pharmacology; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism; D007421:Intestine, Small / Q000378:metabolism*; D007536:Isomerism; D008297:Male; D008353:Mannitol / Q000494:pharmacology; D008715:Methionine / Q000494:pharmacology; D011392:Proline / Q000494:pharmacology; D051381:Rats; D012521:Sarcosine / Q000494:pharmacology
D000596:Amino Acids; D006601:Hexoses; D008353:Mannitol; D011392:Proline; D008715:Methionine; D005947:Glucose; D000409:Alanine; D005690:Galactose; D012521:Sarcosine