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Estimation of allantoin flux using continuous infusion of [14C]allantoin: sensitivity to plasma loading with unlabelled allantoin

Published online by Cambridge University Press:  09 March 2007

L. P. Kahn ,
D. Ouellet  and
J. V. Nolan
L. P. Kahn*
Affiliation:
School of Rural Science and Natural Resources, University of New England, Armidale, NSW 2351, Australia
D. Ouellet
Affiliation:
Canada Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, Lennoxville, Quebec, Canada
J. V. Nolan
Affiliation:
School of Rural Science and Natural Resources, University of New England, Armidale, NSW 2351, Australia
*
*Corresponding author: Dr Lewis P. Khan, fax +61 2 67733275l, email [email protected]
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Abstract

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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 plateau some 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 microbial outflow 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.

Keywords

AllantoinMicrobial nitrogenSheep
Type
Research Article
Information
British Journal of Nutrition , Volume 86 , Issue 6 , December 2001 , pp. 691 - 696
Copyright
Copyright © The Nutrition Society 2001

References

Referenses

Balcells, J, Guada, JA, Castrillo, C & Gasa, J (1991) Urinary excretion of allantoin and allantoin precursors by sheep after different rates of purine infusion into the duodenum. Journal of Agricultural Science, Cambridge 116, 309–317.CrossRefGoogle Scholar
Balcells, J, Parker, DS & Seal, CJ (1992) Purine metabolite concentrations in portal and peripheral blood of steers, sheep and rats. Comparative Biochemistry and Physiology 101B, 633–636.Google Scholar
Chen, XB, Calder, AG, Prasitkusol, P, Kyle, DJ & Jayasuriya, MCN (1998) Determination of 15N isotopic enrichment and concentrations of allantoin and uric acid in urine by gas chromatography/mass spectrometry. Journal of Mass Spectrometry 33, 130–137.3.0.CO;2-Y>CrossRefGoogle ScholarPubMed
Chen, XB, Chen, YK, Franklin, MF, Ørskov, ER & Shand, WJ (1992) The effect of feed intake and body weight on purine derivative excretion and microbial protein supply in sheep. Journal of Animal Science 70, 1534–1542.Google Scholar
Chen, XB, Fujihara, T, Nakamura, K, Mawuenyegah, PO, Franklin, MF & Kyle, DJ (1997) Response of urinary and plasma purine derivatives to various rates and infusion patterns of purines in sheep nourished by intragastric infusion. Journal of Agricultural Science 129, 343–352.CrossRefGoogle Scholar
Chen, XB, Hovell, FDDeB & Ørskov, ER (1990 a) Excretion of purine derivatives by ruminants: recycling of allantoin into the rumen via saliva and its fate in the gut. British Journal of Nutrition 63, 197–205.Google Scholar
Chen, XB, Hovell, FDDeB, Ørskov, ER & Brown, DS (1990 b) Excretion of purine derivatives by ruminants: effect of exogenous nucleic acid supply on purine derivative excretion by sheep. British Journal of Nutrition 63, 131–142.Google Scholar
Chen, XB, Kyle, DJ, Ørskov, ER & Hovell, FDDeB (1991) Renal clearance of plasma allantoin in sheep. Experimental Physiology 76, 59–65.Google Scholar
Kahn, LP & Nolan, JV (2000) Kinetics of allantoin metabolism in sheep. British Journal of Nutrition 84, 629–634.CrossRefGoogle ScholarPubMed
Leng, RA & Leonard, GJ (1965) Measurement of the rates of production of acetic, propionic and butyric acids in the rumen of sheep. British Journal of Nutrition 19, 469–484.CrossRefGoogle ScholarPubMed
McAllan, AB & Smith, RH (1971) Nucleic acids in ruminant digesta as indices of microbial nitrogen. Proceedings of the Nutrition Society 31, 24A.Google Scholar
Shipley, RA & Clark, RE (1972) Tracer Methods for In Vivo Kinetics. New York, NY: Academic Press.Google Scholar
Smith, RH & McAllan, AB, (1970) Nucleic acid metabolism in the ruminant. British Journal of Nutrition 24, 545–556.Google Scholar
Surra, J, Guada, JA, Balcells, J and Castrillo, C (1993) Salivary losses of purine derivatives in sheep.In British Society of Animal Production Winter Meeting, 175–176.Google Scholar
Surra, J, Guada, JA, Balcells, J & Castrillo, C (1997) Renal and salivary clearance of purine derivatives in sheep. Animal Science 65, 83–91.CrossRefGoogle Scholar