Please use this identifier to cite or link to this item: https://une.intersearch.com.au/unejspui/handle/1959.11/240
Title: Estimation of allantoin flux using continuous infusion of [14C]allantoin: Sensitivity to plasma loading with unlabelled allantoin
Contributor(s): Kahn, Lewis (author)orcid ; Ouellet, D (author); Nolan, JV (author)orcid 
Publication Date: 2001
Open Access: Yes
Handle Link: https://hdl.handle.net/1959.11/240
Abstract: Allantoin net flux through the plasma allantoin compartment was determined in sheep given a roughage diet by means of a continuous infusion of [4,5-14C]allantoin for 17 h. Unlabelled allantoin was infused intravenously during the last 7 h of the tracer infusion to increase the allantoin flux by approximately 75%. When unlabelled allantoin was infused, the specific radioactivity of allantoin in plasma and urine declined exponentially to approach a lower plateausome 2–3 h later. The estimate of net flux during the infusion of unlabelled allantoin, estimated from blood plasma and urine, was on average 79 and 90% of expected values. Expected values of allantoin net flux during infusion of unlabelled allantoin were calculated as the sum of allantoin net flux pre-loading plus the known rate of infusion of the allantoin load. It is probable that endogenous allantoin synthesis was decreased by the infusion of allantoin: allosteric inhibition of uricase appears a plausible explanation for this observation, and for lower estimates of net flux. Appearance of labelled allantoin-C in ruminal or blood bicarbonate was negligible. Our results indicate that net flux of allantoin through blood plasma is a good predictor of the entry rate of allantoin into the primary compartment and should be a better predictor of rumen microbialoutflow than urinary allantoin excretion. However, measurements of allantoin-specific radioactivity, during continuous infusion, should be taken after a period of 24 h, at which time the true plateau specific radioactivity value of allantoin in plasma would be attained.
Publication Type: Journal Article
Source of Publication: British Journal of Nutrition, 86(6), p. 691-696
Publisher: Cambridge University Press
Place of Publication: United Kingdom
ISSN: 0007-1145
Field of Research (FOR): 070204 Animal Nutrition
Peer Reviewed: Yes
HERDC Category Description: C1 Refereed Article in a Scholarly Journal
Statistics to Oct 2018: Visitors: 92
Views: 91
Downloads: 10
Appears in Collections:Journal Article
School of Environmental and Rural Science

Files in This Item:
6 files
File Description SizeFormat 
open/SOURCE03.pdfAuthor final version171.16 kBAdobe PDF
Download Adobe
View/Open
open/SOURCE02.pdfPublisher version (open access)92.7 kBAdobe PDF
Download Adobe
View/Open
Show full item record

Page view(s)

88
checked on Dec 29, 2018

Download(s)

16
checked on Dec 29, 2018
Google Media

Google ScholarTM

Check

SCOPUSTM   
Citations

 

Items in Research UNE are protected by copyright, with all rights reserved, unless otherwise indicated.