An important role for endogenous synthesis of arginine in
maintaining arginine homeostasis in neonatal pigs.
Flynn, Nick E., and Guoyao Wu.
Faculty of Nutrition and Departments of Animal Science and Medical
Physiology, Texas A&M University, College Station, Texas 77843
-2471, Tel. 409-845-1817, Fax 409-845-5292
APStracts 3:0183R, 1996.
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 per kg body wt every 4 h during a 12-h period from 6:00 AM
to 6:00 PM. Blood was collected from piglet's jugular vein at 6:00 AM
and 6:00 PM following 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.
Received 12 December 1995; accepted in final form 6 May 1996.
APS Manuscript Number R785-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 May 96