title: Intragastric tryptophan reduces glycemia after glucose, possibly via glucose-mediated insulinotropic polypeptide, in early-weaned piglets.
abstract: The aim of this experiment was to investigate the influence of oral tryptophan on insulin, glucose-mediated insulinotropic polypeptide and glucose concentrations in early-weaned piglets. Piglets were given by intragastric infusion, at the same level of feeding, either a tryptophan-deficient or tryptophan-adequate diet for 22 d. During the experiment blood samples were taken after intragastric infusion of 1) the accustomed meal, 2) a glucose plus tryptophan load and 3) a glucose load. Plasma samples were analyzed for insulin, glucose-mediated insulinotropic polypeptide, glucose and lactate. After the accustomed meal plasma insulin concentrations were augmented and liquid gastric emptying faster in pigs fed tryptophan-adequate compared with tryptophan-deficient diets (P < 0.05) but glucose-mediated insulinotropic polypeptide, glucose and lactate were unaffected. The addition of tryptophan to a glucose load increased glucose-mediated insulinotropic polypeptide and reduced glucose in both tryptophan-adequate and tryptophan-deficient diet fed pigs (P < 0.05). Piglets adapted to the tryptophan-adequate diet had a greater glucose-mediated insulinotropic polypeptide response to intragastric glucose plus tryptophan than piglets adapted to the tryptophan-deficient diet. Adaptation to a tryptophan-adequate diet seems to increase the release of glucose-mediated insulinotropic polypeptide due to infusion of a tryptophan-adequate compared with a tryptophan-deficient diet. The addition of tryptophan to a glucose load reduces the level of glycemia, possibly through glucose-mediated insulinotropic polypeptide-mediated glucose disposal.
authors.affiliation: Institut National de la Recherche Agronomique, Saint-Gilles, France.
authors.forename: A A
authors.initials: AA
authors.lastname: Ponter
authors.forename: B
authors.initials: B
authors.lastname: Sève
authors.forename: L M
authors.initials: LM
authors.lastname: Morgan
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001786:Blood Glucose / Q000032:analysis / Q000187:drug effects*; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects; D005749:Gastric Inhibitory Polypeptide / Q000097:blood / Q000502:physiology*; D005947:Glucose / Q000008:administration & dosage; D007328:Insulin / Q000097:blood; D007773:Lactates / Q000097:blood; D008297:Male; D013552:Swine; D014364:Tryptophan / Q000008:administration & dosage / Q000172:deficiency / Q000494:pharmacology*; D014886:Weaning; D015430:Weight Gain / Q000187:drug effects
chemical_list: D001786:Blood Glucose; D007328:Insulin; D007773:Lactates; D005749:Gastric Inhibitory Polypeptide; D014364:Tryptophan; D005947:Glucose