| Colonic luminal ammonia and portal blood L-glutamine and L-arginine concentrations: a possible link between colon mucosa and liver ureagenesis. | |
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MedLine Citation:
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PMID: 19082688 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The highest ammonia concentration in the body is found in the colon lumen and although there is evidence that this metabolite can be absorbed through the colonic epithelium, there is little information on the capacity of the colonic mucosa to transfer and metabolize this compound. In the present study, we used a model of conscious pig with a canula implanted into the proximal colon to inject endoluminally increasing amounts of ammonium chloride and to measure during 5 h the kinetics of ammonia and amino acid concentration changes in the portal and arterial blood. By injecting as a single dose from 1 to 5 g ammonia into the colonic lumen, a dose-related increase in ammonia concentration in the portal blood was recorded. Ammonia concentration remained unchanged in the arterial blood except for the highest dose tested, i.e. 5 g which thus apparently exceeds the hepatic ureagenesis capacity. By calculating the apparent net ammonia absorption, it was determined that the pig colonic epithelium has the capacity to absorb 4 g ammonia. Ammonia absorption through the colonic epithelium was concomitant with increase of L-glutamine and L-arginine concentrations in the portal blood. This coincided with the expression of both glutamate dehydrogenase and glutamine synthetase in isolated colonic epithelial cells. Since L-glutamine and L-arginine are known to represent activators for liver ureagenesis, we propose that increased portal concentrations of these amino acids following increased ammonia colonic luminal concentration represent a metabolic link between colon mucosa and liver urea biosynthesis. |
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Authors:
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Mamy Eklou-Lawson; Fran??oise Bernard; Nathalie Neveux; Catherine Chaumontet; C??cile Bos; Anne-Marie Davila-Gay; Daniel Tom??; Luc Cynober; Fran??ois Blachier |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2008-12-11 |
Journal Detail:
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Title: Amino acids Volume: 37 ISSN: 1438-2199 ISO Abbreviation: Amino Acids Publication Date: 2009 Oct |
Date Detail:
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Created Date: 2009-09-29 Completed Date: 2010-01-14 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9200312 Medline TA: Amino Acids Country: Austria |
Other Details:
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Languages: eng Pagination: 751-60 Citation Subset: IM |
Affiliation:
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INRA, CNRH-IdF, AgroParisTech, UMR 914 Nutrition Physiology and Ingestive Behavior, 16 rue Claude Bernard, 75005, Paris, France. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Ammonia
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blood,
metabolism* Ammonium Chloride / pharmacology Animals Arginine / analysis, blood, metabolism* Glutamate Dehydrogenase / drug effects, metabolism Glutamate-Ammonia Ligase / drug effects, metabolism Glutamine / analysis, blood, metabolism* Intestinal Mucosa / drug effects, metabolism* Liver / drug effects, metabolism* Portal Vein / metabolism* Sus scrofa Urea / agonists, blood, metabolism* |
| Chemical | |
Reg. No./Substance:
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12125-02-9/Ammonium Chloride; 56-85-9/Glutamine; 57-13-6/Urea; 74-79-3/Arginine; 7664-41-7/Ammonia; EC 1.4.1.2/Glutamate Dehydrogenase; EC 6.3.1.2/Glutamate-Ammonia Ligase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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