Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3 Pt 1
pubmed:dateCreated
1996-12-5
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.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
271
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
E563-73
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Diurnal pattern of the interrelationships among leucine oxidation, urea production, and hydrolysis in humans.
pubmed:affiliation
Laboratory of Human Nutrition, School of Science and Clinical Research Center, Massachusetts Institute of Technology, Cambridge 02139, USA. antoine@crc.mit.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.