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The importance of transmethylation reactions to methionine metabolism in sheep: effects of supplementation with creatine and choline

Published online by Cambridge University Press:  09 March 2007

G. E. Lobley ,
A. Connell  and
D. Revell
G. E. Lobley
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
A. Connell
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
D. Revell
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
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Abstract

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The influence of administering the methylated products choline and creatine on methionine irreversible loss rate (ILR) and recycling from homocysteine has been investigated in sheep fed close to energy and N equilibrium. Two methods to estimate methionine recycling were compared. The first involved & [U-13C& ]methionine infused as part of a labelled amino acid mixture obtained from hydrolysed algal protein. In this approach the isotope dilution of methionine with all five C atoms labelled (m+5) will represent the ILR which does not recycle through homocysteine, while that which includes molecules with C-l–C-4 labelled will allow for loss of the labelled methyl (5)-C atom and replacement by an unlabelled moiety in the remethylation of homocysteine. The second method involved a combined infusion of [l-13C]- & [S-methyl-2H3& rsqb;methionine. These two approaches gave similar data for methionine ILR which does not include label recycled to the amino acid from homocysteine but differed for recycled methionine fluxes. Consequently the two procedures differed in the calculated extent of homocysteine methylation under control conditions (6 v. 28). These extents of remethylation are within the range observed for the fed human subject, despite the fact that fewer dietary methyl groups are available for the ruminant. Using combined data from the infwions, significant depression of methionine recycling occurred in blood (P <0·05), with a similar trendfor plasma (P = 0·077), when choline plus creatine were infused. Wool growth, assessed by intradermal injection of [35S]cysteine, was not altered by supplementation with the methylated products. From changes in the label pattern of free methionine in aortal, hepatic portal and hepatic venous blood during U-13C-labelled algal hydrolysate infusion, the major sites of homocysteine remethylation appear to be the portal-drained viscera and the liver. This was confirmed by analysis of free methionine enrichments in various tissues following dual infusion of & [1J3C& ]- and & [S-methyl-2H3methionine, with the greatest activities occurring in rumen, jejunum and liver. Of the non-splanchnic tissues examined, only kidney exhibited substantial methionine cycling; none was detected in muscle, heart, lung and skin. The implications of methyl group provision under net prduction conditions are discussed.

Keywords

MethioniueMethylationStable isotopesWool growth
Type
Amino acid metabolism
Information
British Journal of Nutrition , Volume 75 , Issue 1 , January 1996 , pp. 47 - 56
Copyright
Copyright © The Nutrition Society 1996

References

REFERENCES

Aurousseau, B., Connell, A., Revell, D. K., Rocha, H. J. G. & Lobley, G. E. (1993). Hind-limb protein metabolism in growing sheep: effects of acute and chronic infusion of clenbuterol by close arterial and systemic routes. Comparative Biochemistry and Physiology 106C, 529–535.Google ScholarPubMed
Bardocz, S., Grant, G., Brown, D. S. & Pusztai, A. (1989). Stimulation of polyamine synthesis and growth of the small intestine by dietary kidney bean lectin. In Recent Advances of Research in Antinutritional Factors in Legume Seeds, pp. 39–42 & [Huisman, J., van der Poet, T. F. B. and Liener, J. E., editors]. Wageningen: Pudoc.Google Scholar
Benevenga, N. J., Radcliffe, B. C. & Egan, A. R. (1983). Tissue metabolism of methionine in sheep. Australian Journal of Biological Sciences 36, 475–485.CrossRefGoogle ScholarPubMed
Boss, G. R. (1985). Cobalamin inactivation decreases purine and methionine synthesis in cultured lymphoblasts. Journal of Clinical Investigation 76, 213–218.CrossRefGoogle ScholarPubMed
Calder, A. G. & Smith, A. (1988). Stable isotope ratio analysis of leucine and ketoisocaproic acid in blood plasma by gas chromatographys/mass spectrometry. Rapid Communications in Mass Spectrometry 2, 14–16.CrossRefGoogle Scholar
Campbell, I. M. (1974). Incorporation and dilution values – their calculation in mass spectrally assayed stable isotope labelling experiments. Bioorganic Chemistry 3, 386–397.CrossRefGoogle Scholar
Dawson, R. M. C., Grime, D. W. & Lindsay, D. B. (1981). On the insensitivity of sheep to the almost complete microbial destruction of dietary choline before alimentary tract absorption. Biochemical Journal 196, 499–504.CrossRefGoogle Scholar
Emmanuel, B. & Kennelly, J. J. (1984). Kinetics of methionine and choline and their incorporation into plasma lipids and milk components in lactating goats. Journal of Dairy Science 67, 1912–1918.CrossRefGoogle ScholarPubMed
Ferger, M. F. & Vigneaud, V. (1950). Oxidation in vivo of the methyl groups of choline, betaine, dimethylthetin and dimethyl-β3-propiothetin. Journal of Biological Chemistry 185, 53–57.CrossRefGoogle Scholar
Finkelstein, J. D. & Martin, J. J. (1984). Methionine metabolism in mammals. Distribution of homocysteine between competing pathways. Journal of Biological Chemistry 259, 9508–9513.CrossRefGoogle ScholarPubMed
Genstat 5 (1987). Genstat 5 Reference Manual. Rothamsted Experimental Station. Oxford: Clarendon Press.Google Scholar
Gill, M. & Ulyatt, M. J. (1979). The metabolism of methionine in silage-fed sheep. British Journalof Nutrition 41, 605–609.CrossRefGoogle Scholar
Henderson, G. D., Xue, G.-P. & Snoswell, A. M. (1983). Carnitine and creatine content of tissues of normal and alloxan-diabetic sheep and rats. Comparative Biochemistry and Physiology 76B, 295–298.Google ScholarPubMed
Lobley, G. E., Connell, A., Revell, D. K., Brown, D. S. & Calder, A. G. (1996). Mass and kinetic amino acid transfers across the ovine splanchnic bed: transport in blood and plasma, monitored through use of a multiple & [U-I3C& ] amino acid mixture in response to choline plus creatine supplementation. British Journal of Nutrition (In the Press).Google ScholarPubMed
Mudd, S. H. & Pool, J. R. (1975). Labile methyl balances for normal humans on various dietary regimens. Metabolism 24, 721–735.CrossRefGoogle ScholarPubMed
Neill, A. R., Grime, D. W., Snoswell, A. M., Northrop, A. J., Lindsay, D. B. & Dawson, R. M. C. (1979). The low availability of dietary choline for the nutrition of the sheep. Biochemical Journal 180, 559–565.CrossRefGoogle ScholarPubMed
Pisulewski, P. M. & Buttery, P. J. (1985). The effect of increasing methionine supply on the methionine conversion to cyst(e)ine in sheep. British Journal of Nutrition 54, 121–129.CrossRefGoogle ScholarPubMed
Sharma, B. K. & Erdman, R. A. (1988). Abomasal infusion of choline and methionine with or without 2-amino-2-methyl-l-propanol for lactating dairy cows. Journal of Dairy Science 71, 2406–2411.CrossRefGoogle Scholar
Storch, K. J., Wagner, D. A., Burke, J. F. & Young, V. R. (1988). Quantitative study in vivo of methionine cycle in humans using [methyL2H,]- and [l-13C]methionine. American Journal of Physiology 255, E322–331.Google ScholarPubMed
Walker, J. B. (1960). Metabolic control of creatine biosynthesis. 1. Effect of dietary creatine. Journal of Biological Chemistry 235, 2357–2361.CrossRefGoogle Scholar
Xue, G.-P. & Snoswell, A. M. (1985). Comparative studies on the methionine synthesis in sheep and rat tissues. Comparative Biochemistry and Physiology 80B, 489–494.Google ScholarPubMed
Xue, G.-P. & Snoswell, A. M. (1986). Developmental changes in the activities of enzymes related to methyl group metabolism in sheep tissues. Comparative Biochemistry and Physiology 83B, 115–120.Google ScholarPubMed