|
|
||||||||
Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland, Canada A1B 3X9
The rates of oxidation of arginine and ornithine that
occurred through a reaction pathway involving the enzyme ornithine
aminotransferase (EC 2.6.1.13) were determined using
14C-labeled amino acids in the isolated nonrecirculating
perfused rat liver. At physiological concentrations of these amino
acids, their catabolism is subject to chronic regulation by the level of protein consumed in the diet. 14CO2
production from [U-14C]ornithine (0.1 mM) and
from [U-14C]arginine (0.2 mM) was increased
about fourfold in livers from rats fed 60% casein diets for 3-4
days. The catabolism of arginine in the perfused rat liver, but not
that of ornithine, is subject to acute regulation by glucagon
(10
7 M), which stimulated arginine
catabolism by ~40%. Dibutyryl cAMP (0.1 mM) activated arginine
catabolism to a similar extent. In retrograde perfusions, glucagon
caused a twofold increase in the rate of arginine catabolism,
suggesting an effect of glucagon on arginase in the perivenous cells.
hepatic zonation; high-protein diet; antegrade and retrograde perfusion
This article has been cited by other articles:
![]() |
M. Jourdan, L. Cynober, C. Moinard, M. C. Blanc, N. Neveux, J. P. De Bandt, and C. Aussel Splanchnic sequestration of amino acids in aged rats: in vivo and ex vivo experiments using a model of isolated perfused liver Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R748 - R755. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Mouille, V. Robert, and F. Blachier Adaptative increase of ornithine production and decrease of ammonia metabolism in rat colonocytes after hyperproteic diet ingestion Am J Physiol Gastrointest Liver Physiol, August 1, 2004; 287(2): G344 - G351. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. Nissim, O. Horyn, Y. Daikhin, I. Nissim, A. Lazarow, and M. Yudkoff Regulation of urea synthesis by agmatine in the perfused liver: studies with 15N Am J Physiol Endocrinol Metab, December 1, 2002; 283(6): E1123 - E1134. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |