Tags

Type your tag names separated by a space and hit enter

Interorgan amino acid exchange in humans: consequences for arginine and citrulline metabolism.
Am J Clin Nutr. 2007 Jan; 85(1):167-72.AJ

Abstract

BACKGROUND

The liver plays a central role in amino acid metabolism. However, because of limited accessibility of the portal vein, human data on this subject are scarce.

OBJECTIVE

We studied hepatic amino acid metabolism in noncirrhotic fasting patients undergoing liver surgery.

DESIGN

Twenty patients undergoing hepatectomy for colorectal metastases in a normal liver were studied. Before resection, blood was sampled from a radial artery, portal vein, hepatic vein, and renal vein. Organ blood flow was measured by duplex ultrasound scan.

RESULTS

The intestine consumed glutamine and released citrulline. Citrulline was taken up by the kidney. This was accompanied by renal arginine release, which supports the view that glutamine is a precursor for arginine synthesis through an intestinal-renal pathway. The liver was found to extract citrulline from this pathway at a rate that was dependent on intestinal citrulline release (P < 0.0001) and hepatic citrulline influx (P = 0.03). Fractional hepatic extractions of citrulline (8.4%) and arginine (11.5%) were not significantly different. Eighty-eight percent of arginine reaching the liver passed it unchanged. Splanchnic citrulline release could account for one-third of renal citrulline uptake.

CONCLUSIONS

This is the first study of hepatic and interorgan amino acid metabolism in humans with a normal liver. The data indicate that glutamine is a precursor of ornithine, which can be converted to citrulline by the intestine; citrulline is transformed in the kidneys to arginine. Hepatic citrulline uptake limits the amount of gut-derived citrulline reaching the kidney. These findings may have implications for interventions aimed at increasing systemic arginine concentrations.

Authors+Show Affiliations

Department of Surgery, Nutrition and Toxicology Institute Maastricht, Maastricht University and University Hospital Maastricht, Netherlands. mcg.vandepoll@ah.unimaas.nlNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17209193

Citation

van de Poll, Marcel C G., et al. "Interorgan Amino Acid Exchange in Humans: Consequences for Arginine and Citrulline Metabolism." The American Journal of Clinical Nutrition, vol. 85, no. 1, 2007, pp. 167-72.
van de Poll MC, Siroen MP, van Leeuwen PA, et al. Interorgan amino acid exchange in humans: consequences for arginine and citrulline metabolism. Am J Clin Nutr. 2007;85(1):167-72.
van de Poll, M. C., Siroen, M. P., van Leeuwen, P. A., Soeters, P. B., Melis, G. C., Boelens, P. G., Deutz, N. E., & Dejong, C. H. (2007). Interorgan amino acid exchange in humans: consequences for arginine and citrulline metabolism. The American Journal of Clinical Nutrition, 85(1), 167-72.
van de Poll MC, et al. Interorgan Amino Acid Exchange in Humans: Consequences for Arginine and Citrulline Metabolism. Am J Clin Nutr. 2007;85(1):167-72. PubMed PMID: 17209193.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Interorgan amino acid exchange in humans: consequences for arginine and citrulline metabolism. AU - van de Poll,Marcel C G, AU - Siroen,Michiel P C, AU - van Leeuwen,Paul A M, AU - Soeters,Peter B, AU - Melis,Gerdien C, AU - Boelens,Petra G, AU - Deutz,Nicolaas E P, AU - Dejong,Cornelis H C, PY - 2007/1/9/pubmed PY - 2007/2/16/medline PY - 2007/1/9/entrez SP - 167 EP - 72 JF - The American journal of clinical nutrition JO - Am. J. Clin. Nutr. VL - 85 IS - 1 N2 - BACKGROUND: The liver plays a central role in amino acid metabolism. However, because of limited accessibility of the portal vein, human data on this subject are scarce. OBJECTIVE: We studied hepatic amino acid metabolism in noncirrhotic fasting patients undergoing liver surgery. DESIGN: Twenty patients undergoing hepatectomy for colorectal metastases in a normal liver were studied. Before resection, blood was sampled from a radial artery, portal vein, hepatic vein, and renal vein. Organ blood flow was measured by duplex ultrasound scan. RESULTS: The intestine consumed glutamine and released citrulline. Citrulline was taken up by the kidney. This was accompanied by renal arginine release, which supports the view that glutamine is a precursor for arginine synthesis through an intestinal-renal pathway. The liver was found to extract citrulline from this pathway at a rate that was dependent on intestinal citrulline release (P < 0.0001) and hepatic citrulline influx (P = 0.03). Fractional hepatic extractions of citrulline (8.4%) and arginine (11.5%) were not significantly different. Eighty-eight percent of arginine reaching the liver passed it unchanged. Splanchnic citrulline release could account for one-third of renal citrulline uptake. CONCLUSIONS: This is the first study of hepatic and interorgan amino acid metabolism in humans with a normal liver. The data indicate that glutamine is a precursor of ornithine, which can be converted to citrulline by the intestine; citrulline is transformed in the kidneys to arginine. Hepatic citrulline uptake limits the amount of gut-derived citrulline reaching the kidney. These findings may have implications for interventions aimed at increasing systemic arginine concentrations. SN - 0002-9165 UR - https://www.unboundmedicine.com/medline/citation/17209193/Interorgan_amino_acid_exchange_in_humans:_consequences_for_arginine_and_citrulline_metabolism_ L2 - https://academic.oup.com/ajcn/article-lookup/doi/10.1093/ajcn/85.1.167 DB - PRIME DP - Unbound Medicine ER -