Quantitative aspects of inter-organ relationships among arginine
and citrulline metabolism.
Yu, Yong-Ming, John F. Burke, Ronald G. Tompkins, Ramon Martin, and
Vernon R. Young.
Shriners Burns Institute and Department of Surgery, Massachusetts
General Hospital, Boston MA 02114; Laboratory of Human Nutrition,
Massachusetts Institute of Technology, Cambridge MA 02139
APStracts 3:0170E, 1996.
Quantitative Aspects of Inter-Organ Relationships Among Arginine and
Citrulline Metabolism Am. J. Physiol. -- The quantitative roles of
the splanchnic (SP) region and of the kidneys in whole body (WB)
arginine and citrulline metabolism were assessed in post-absorptive
mongrel dogs, with primed, constant intravenous infusions of [15N2
-guanidino, 5,5,2H2]arginine and [13C-ureido]citrulline or of [13C
-guanidino]arginine and [15N]urea tracers. Isotope and metabolite
concentration balances of arginine and citrulline were measured
across the gut, liver, SP and kidneys together with their WB fluxes
and urea production rate. The WB citrulline flux and rate of
citrulline to arginine conversion (C-A) was 16 and 9.4 [mu]mol.kg-1.
h-1, respectively. Concentration balance of citrulline across kidneys
was +8.2 [mu]mol.kg-1.h-1, metabolism of citrulline by kidneys was
8.7 [mu]mol.kg-1 .h-1, derived about equally from intestine and
liver. The appearance rate of citrulline-derived-arginine in renal
vein was 6.8 [mu]mol.kg-1.h-1. These three separate estimates of C-A
within the kidneys were in good agreement, indicating 40% of blood C
-A occurring outside kidneys. These findings of interorgan metabolism
are discussed in reference to the current knowledge derived largely
from studies in laboratory rodents.
Received 19 April 1996; accepted in final form 12 August 1996.
APS Manuscript Number E199-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 29 August 1996