AJP - Endocrinology and Metabolism, Vol 269, Issue 6 E996-E999, Copyright © 1995 by American Physiological Society

ARTICLES

Gut mucosal protein synthesis measured using intravenous and intragastric delivery of stable tracer amino acids

I. M. Nakshabendi, W. Obeidat, R. I. Russell, S. Downie, K. Smith and M. J. Rennie
Department of Gastroenterology, Royal Infirmary, Glasgow, United Kingdom.

We measured the rates of mucosal protein synthesis during the simultaneous delivery of [1-13C]leucine and [1-13C]valine delivered either intragastrically or intravenously to investigate any influence of the route of supply of the tracers. Dependent on the route, there were marked differences in the gradient of labeling between the plasma and intramucosal leucine and valine; i.e., for intravenous tracers the ratio was 1.73 +/- 0.16, but for intragastric tracers it was 0.65 +/- 0.12 (P < 0.05). Incorporation of intravenous tracer into mucosal protein was linear with time, and irrespective of tracer route, the calculated fractional rates of protein synthesis were identical when based on the intracellular labeling of the leucine or valine tracer, i.e., with intravenous 2.58 +/- 0.32%/h and with intragastric 2.45 +/- 0.36%/h. The results demonstrate that a robust and reproducible method of measurement of gastrointestinal mucosal protein synthesis has been developed and that use of either intragastric or intravenous routes of tracer administration gives comparable results. The high rates measured suggest that the gastrointestinal mucosa contributes substantially to whole body protein synthesis in normal healthy subjects.

This article has been cited by other articles:

				P. Rittler, B. Schiefer, H. Demmelmair, B. Koletzko, M. Vogeser, D. H. Alpers, K.-W. Jauch, and W. H. Hartl The Effect of Hyperglycemic Hyperinsulinemia on Small-Intestinal Mucosal Protein Synthesis in Patients After Surgical Stress JPEN J Parenter Enteral Nutr, March 1, 2006; 30(2): 97 - 107. [Abstract] [Full Text] [PDF]

				M. Coeffier, S. Claeyssens, B. Hecketsweiler, A. Lavoinne, P. Ducrotte, and P. Dechelotte Enteral glutamine stimulates protein synthesis and decreases ubiquitin mRNA level in human gut mucosa Am J Physiol Gastrointest Liver Physiol, July 7, 2003; 285(2): G266 - G273. [Abstract] [Full Text] [PDF]

				C. Duggan, J. Gannon, and W A. Walker Protective nutrients and functional foods for the gastrointestinal tract Am. J. Clinical Nutrition, May 1, 2002; 75(5): 789 - 808. [Abstract] [Full Text] [PDF]

				C. Morens, C. Gaudichon, G. Fromentin, A. Marsset-Baglieri, A. Bensaid, C. Larue-Achagiotis, C. Luengo, and D. Tome Daily delivery of dietary nitrogen to the periphery is stable in rats adapted to increased protein intake Am J Physiol Endocrinol Metab, October 1, 2001; 281(4): E826 - E836. [Abstract] [Full Text] [PDF]

				P. Crenn, F. Thuillier, B. Rakatoambinina, M. Rongier, D. Darmaun, and B. Messing Duodenal vs. gastric administration of labeled leucine for the study of splanchnic metabolism in humans J Appl Physiol, August 1, 2000; 89(2): 573 - 580. [Abstract] [Full Text] [PDF]

				R. Ing, Z. Su, M. E. Scott, and K. G. Koski Suppressed T helper 2 immunity and prolonged survival of a nematode parasite in protein-malnourished mice PNAS, June 20, 2000; 97(13): 7078 - 7083. [Abstract] [Full Text] [PDF]

				C. Bouteloup-Demange, S. Claeyssens, C. Maillot, A. Lavoinne, E. Lerebours, and P. Dechelotte Effects of enteral glutamine on gut mucosal protein synthesis in healthy humans receiving glucocorticoids Am J Physiol Gastrointest Liver Physiol, May 1, 2000; 278(5): G677 - G681. [Abstract] [Full Text] [PDF]

				M. E. Scott and K. G. Koski Zinc Deficiency Impairs Immune Responses against Parasitic Nematode Infections at Intestinal and Systemic Sites J. Nutr., May 1, 2000; 130(5): 1412S - 1420. [Abstract] [Full Text]

				P. Rittler, H. Demmelmair, B. Koletzko, F. W. Schildberg, and W. H. Hartl Determination of protein synthesis in human ileum in situ by continuous [1-13C]leucine infusion Am J Physiol Endocrinol Metab, April 1, 2000; 278(4): E634 - E638. [Abstract] [Full Text] [PDF]

				I. M. Nakshabendi, R. McKee, S. Downie, R. I. Russell, and M. J. Rennie Rates of small intestinal mucosal protein synthesis in human jejunum and ileum Am J Physiol Endocrinol Metab, December 1, 1999; 277(6): E1028 - E1031. [Abstract] [Full Text] [PDF]

				J. S. Marchini, P. Nguyen, J.-Y. Deschamps, P. Maugere, M. Krempf, and D. Darmaun Effect of intravenous glutamine on duodenal mucosa protein synthesis in healthy growing dogs Am J Physiol Endocrinol Metab, April 1, 1999; 276(4): E747 - E753. [Abstract] [Full Text] [PDF]

				O. A. J. Adegoke, M. I. McBurney, and V. E. Baracos Jejunal mucosal protein synthesis: validation of luminal flooding dose method and effect of luminal osmolarity Am J Physiol Gastrointest Liver Physiol, January 1, 1999; 276(1): G14 - G20. [Abstract] [Full Text] [PDF]

				B. Stoll, D. G. Burrin, J. F. Henry, F. Jahoor, and P. J. Reeds Dietary and systemic phenylalanine utilization for mucosal and hepatic constitutive protein synthesis in pigs Am J Physiol Gastrointest Liver Physiol, January 1, 1999; 276(1): G49 - G57. [Abstract] [Full Text] [PDF]

				C. Bouteloup-Demange, Y. Boirie, P. Dechelotte, P. Gachon, and B. Beaufrere Gut mucosal protein synthesis in fed and fasted humans Am J Physiol Endocrinol Metab, March 1, 1998; 274(3): E541 - E546. [Abstract] [Full Text] [PDF]

				B. Stoll, D. G. Burrin, J. Henry, F. Jahoor, and P. J. Reeds Phenylalanine utilization by the gut and liver measured with intravenous and intragastric tracers in pigs Am J Physiol Gastrointest Liver Physiol, December 1, 1997; 273(6): G1208 - G1217. [Abstract] [Full Text] [PDF]

				A. E. Halseth, P. J. Flakoll, E. K. Reed, A. B. Messina, M. G. Krishna, D. B. Lacy, P. E. Williams, and D. H. Wasserman Effect of physical activity and fasting on gut and liver proteolysis in the dog Am J Physiol Endocrinol Metab, December 1, 1997; 273(6): E1073 - E1082. [Abstract] [Full Text] [PDF]