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Intestinal and hepatic metabolism of glutamine and citrulline in humans.
J Physiol 2007; 581(Pt 2):819-27JP

Abstract

Glutamine plays an important role in nitrogen homeostasis and intestinal substrate supply. It has been suggested that glutamine is a precursor for arginine through an intestinal-renal pathway involving inter-organ transport of citrulline. The importance of intestinal glutamine metabolism for endogenous arginine synthesis in humans, however, has remained unaddressed. The aim of this study was to investigate the intestinal conversion of glutamine to citrulline and the effect of the liver on splanchnic citrulline metabolism in humans. Eight patients undergoing upper gastrointestinal surgery received a primed continuous intravenous infusion of [2-(15)N]glutamine and [ureido-(13)C-(2)H(2)]citrulline. Arterial, portal venous and hepatic venous blood were sampled and portal and hepatic blood flows were measured. Organ specific amino acid uptake (disposal), production and net balance, as well as whole body rates of plasma appearance were calculated according to established methods. The intestines consumed glutamine at a rate that was dependent on glutamine supply. Approximately 13% of glutamine taken up by the intestines was converted to citrulline. Quantitatively glutamine was the only important precursor for intestinal citrulline release. Both glutamine and citrulline were consumed and produced by the liver, but net hepatic flux of both amino acids was not significantly different from zero. Plasma glutamine was the precursor of 80% of plasma citrulline and plasma citrulline in turn was the precursor of 10% of plasma arginine. In conclusion, glutamine is an important precursor for the synthesis of arginine after intestinal conversion to citrulline in humans.

Authors+Show Affiliations

Department of Surgery, University Hospital Maastricht and Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, PO Box 616, 6200 MD, Maastricht, the Netherlands.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17347276

Citation

van de Poll, Marcel C G., et al. "Intestinal and Hepatic Metabolism of Glutamine and Citrulline in Humans." The Journal of Physiology, vol. 581, no. Pt 2, 2007, pp. 819-27.
van de Poll MC, Ligthart-Melis GC, Boelens PG, et al. Intestinal and hepatic metabolism of glutamine and citrulline in humans. J Physiol (Lond). 2007;581(Pt 2):819-27.
van de Poll, M. C., Ligthart-Melis, G. C., Boelens, P. G., Deutz, N. E., van Leeuwen, P. A., & Dejong, C. H. (2007). Intestinal and hepatic metabolism of glutamine and citrulline in humans. The Journal of Physiology, 581(Pt 2), pp. 819-27.
van de Poll MC, et al. Intestinal and Hepatic Metabolism of Glutamine and Citrulline in Humans. J Physiol (Lond). 2007 Jun 1;581(Pt 2):819-27. PubMed PMID: 17347276.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intestinal and hepatic metabolism of glutamine and citrulline in humans. AU - van de Poll,Marcel C G, AU - Ligthart-Melis,Gerdien C, AU - Boelens,Petra G, AU - Deutz,Nicolaas E P, AU - van Leeuwen,Paul A M, AU - Dejong,Cornelis H C, Y1 - 2007/03/08/ PY - 2007/3/10/pubmed PY - 2007/7/12/medline PY - 2007/3/10/entrez SP - 819 EP - 27 JF - The Journal of physiology JO - J. Physiol. (Lond.) VL - 581 IS - Pt 2 N2 - Glutamine plays an important role in nitrogen homeostasis and intestinal substrate supply. It has been suggested that glutamine is a precursor for arginine through an intestinal-renal pathway involving inter-organ transport of citrulline. The importance of intestinal glutamine metabolism for endogenous arginine synthesis in humans, however, has remained unaddressed. The aim of this study was to investigate the intestinal conversion of glutamine to citrulline and the effect of the liver on splanchnic citrulline metabolism in humans. Eight patients undergoing upper gastrointestinal surgery received a primed continuous intravenous infusion of [2-(15)N]glutamine and [ureido-(13)C-(2)H(2)]citrulline. Arterial, portal venous and hepatic venous blood were sampled and portal and hepatic blood flows were measured. Organ specific amino acid uptake (disposal), production and net balance, as well as whole body rates of plasma appearance were calculated according to established methods. The intestines consumed glutamine at a rate that was dependent on glutamine supply. Approximately 13% of glutamine taken up by the intestines was converted to citrulline. Quantitatively glutamine was the only important precursor for intestinal citrulline release. Both glutamine and citrulline were consumed and produced by the liver, but net hepatic flux of both amino acids was not significantly different from zero. Plasma glutamine was the precursor of 80% of plasma citrulline and plasma citrulline in turn was the precursor of 10% of plasma arginine. In conclusion, glutamine is an important precursor for the synthesis of arginine after intestinal conversion to citrulline in humans. SN - 0022-3751 UR - https://www.unboundmedicine.com/medline/citation/17347276/Intestinal_and_hepatic_metabolism_of_glutamine_and_citrulline_in_humans_ L2 - https://doi.org/10.1113/jphysiol.2006.126029 DB - PRIME DP - Unbound Medicine ER -