title: An important role for endogenous synthesis of arginine in maintaining arginine homeostasis in neonatal pigs.
abstract: This study was designed to test the hypothesis that endogenous arginine synthesis plays an important role in maintaining arginine homeostasis in neonatal pigs. Gabaculine was used as a suicide inhibitor of ornithine aminotransferase to decrease the intestinal conversion of glutamine-derived pyrroline-5-carboxylate (P-5-C) into ornithine, the precursor of both citrulline and arginine. Four-day-old suckling pigs received oral administration of 0.0 or 0.83 mg gabaculine/kg body wt every 4 h during a 12-h period from 6 A.M. to 6 P.M. Blood was collected from piglet's jugular vein at 6 A.M. and 6 P.M. after a 2-h isolation from sows. Gabaculine treatment decreased plasma concentrations of ornithine, citrulline, and arginine by 59, 52, and 76%, respectively, and increased those of glutamine and proline by 74 and 220%, respectively. The gabaculine treatment also increased plasma concentrations of leucine, taurine, and ammonia by 29, 42, and 20%, respectively. There were no differences in intramuscular concentrations of amino acids between control and gabaculine-treated pigs. Because P-5-C synthase (the enzyme required for synthesis of P-5-C from glutamate) was almost exclusively located in enterocytes of 4-day-old pigs, our data suggest that the intestinal production of citrulline plays an important role in endogenous synthesis of arginine and its homeostasis in neonatal pigs.
authors.affiliation: Faculty of Nutrition, Texas A&M University, College Station 77843-2471, USA.
authors.forename: N E
authors.initials: NE
authors.lastname: Flynn
authors.forename: G
authors.initials: G
authors.lastname: Wu
mesh_terms: D000284:Administration, Oral; D000596:Amino Acids / Q000097:blood / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001120:Arginine / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002956:Citrulline / Q000037:antagonists & inhibitors; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology; D005973:Glutamine / Q000378:metabolism; D006706:Homeostasis; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000166:cytology; D018482:Muscle, Skeletal / Q000378:metabolism; D009952:Ornithine / Q000037:antagonists & inhibitors; D009953:Ornithine-Oxo-Acid Transaminase / Q000378:metabolism; D011758:Pyrroles / Q000378:metabolism; D013552:Swine
chemical_list: D000596:Amino Acids; D003509:Cyclohexanecarboxylic Acids; D011758:Pyrroles; D005973:Glutamine; C015485:delta-1-pyrroline-5-carboxylate; D002956:Citrulline; C012987:gabaculine; D001120:Arginine; D009952:Ornithine; D009953:Ornithine-Oxo-Acid Transaminase