Journal of Nutrition OpenSOurce Diets- www.ResearchDiets.com

Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
QUICK SEARCH:   [advanced]


     

Journal of Nutrition Vol. 123 No. 12 December 1993, pp. 2129-2136
Copyright © 1993 by American Society for Nutrition
This Article
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Jackson, A. A.
Right arrow Articles by Boyes, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Jackson, A. A.
Right arrow Articles by Boyes, S.

A Noninvasive Method for Measuring Urea Kinetics with a Single Dose of [15N15N]Urea in Free-Living Humans1,2,

Alan A. Jackson3, Mark S. Danielsen and Simon Boyes

Department of Human Nutrition, University of Southampton, Southampton SO9 3TU, U.K.

A noninvasive method is described in which the endogenous rate of urea production can be determined in normal, free-living adults. A single dose of [15N15N]urea was given orally, and the amount of label excreted as [15N15N]urea and [15N14N]urea in urine over the subsequent 48 h was measured. From the rates of excretion of labeled and unlabeled urea the rate of urea production was derived. Using this single-dose protocol the rate of urea production was 207 ± 56 (mean ± SD) mg N/(kg·d) in six normal adult men consuming 74 g protein/d. These results were not different when compared with rates of urea production obtained with a prime/intermittent protocol in an earlier study in the same individuals [199 ± 20 mg N/(kg·d)]. We conclude that urea kinetics can be measured noninvasively with a single dose of [15N15N]urea and that this method may be suitable for use in free-living individuals to determine urea production rates for habitual dietary intakes.

KEY WORDS: • humans • nitrogen • protein • amino acids • respiratory quotient

1 Personal support was provided as an MRC studentship to MD. Support towards the purchase of the mass spectrometer was provided by the Rank Foundation, the Rank Prize Funds, the Hedley Trust and the Wessex Medical Trust.

2 The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 USC section 1734 solely to indicate this fact.

3 To whom correspondence should be addressed.

Manuscript received 8 February 1993. Initial review completed 24 March 1993. Revision accepted 28 July 1993.






Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]