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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
3 Pt 1
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pubmed:dateCreated |
1996-12-5
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pubmed:abstractText |
We investigated in six healthy adult men, who received an adequate intake of protein (1 g.kg-1.day-1), the relationship among urea production, excretion, and hydrolysis. At the end of a 6-day diet-adjustment period, subjects were studied using a 24-h continuous intravenous [1-13C]leucine and [15N,15N]urea tracer protocol (A. E. El-Khoury, N. K. Fukagawa, M. Sánchez, R. H. Tsay, R. E. Gleason, T. E. Chapman, and V. R. Young. Am. J. Clin. Nutr. 59: 1000-1011, 1994) to determine rates of irreversible protein nitrogen loss and urea kinetics. By combining leucine and urea kinetic data, we found a significant degree of urea hydrolysis over the 24-h period but no evidence to support the thesis that there is a net retention or "salvage" of the urea nitrogen liberated. Our measurements revealed little or no urea hydrolysis during the fed 12-h period of the 24-h tracer protocol but substantial hydrolysis during the 12-h fasting phase. Furthermore, a mass balance model and calculations (APPENDIX) indicated that nitrogen salvage, if any, is quantitatively indistinguishable from insensible nitrogen losses and aggregate estimation errors, accounting for no more than 5% of the nitrogen intake. We conclude that urea hydrolysis, via the intestinal microflora, although representing a component of the overall cycles of nitrogen flow within the body, does not contribute via a net retention of amino nitrogen to the maintenance of body nitrogen homeostasis in healthy adults consuming an adequate diet.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Sep
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pubmed:issn |
0002-9513
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
271
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
E563-73
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:8843752-Adult,
pubmed-meshheading:8843752-Circadian Rhythm,
pubmed-meshheading:8843752-Humans,
pubmed-meshheading:8843752-Hydrolysis,
pubmed-meshheading:8843752-Leucine,
pubmed-meshheading:8843752-Male,
pubmed-meshheading:8843752-Models, Biological,
pubmed-meshheading:8843752-Nitrogen Compounds,
pubmed-meshheading:8843752-Oxidation-Reduction,
pubmed-meshheading:8843752-Urea
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pubmed:year |
1996
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pubmed:articleTitle |
Diurnal pattern of the interrelationships among leucine oxidation, urea production, and hydrolysis in humans.
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pubmed:affiliation |
Laboratory of Human Nutrition, School of Science and Clinical Research Center, Massachusetts Institute of Technology, Cambridge 02139, USA. antoine@crc.mit.edu
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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