Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-23T15:53:30.008Z Has data issue: false hasContentIssue false
  • English
  • Français

Metabolism of leucine by the isolated perfused goat udder

Published online by Cambridge University Press:  01 June 2009

Eddy Roets ,
Anne-Marie Massart-Leën ,
Georges Peeters  and
Roger Verbeke
Eddy Roets
Affiliation:
Department of Physiology, Veterinary Faculty of the University of Ghent, Casinoplein 24, B-9000 Ghent, Belgium
Anne-Marie Massart-Leën
Affiliation:
Department of Physiology, Veterinary Faculty of the University of Ghent, Casinoplein 24, B-9000 Ghent, Belgium
Georges Peeters
Affiliation:
Department of Physiology, Veterinary Faculty of the University of Ghent, Casinoplein 24, B-9000 Ghent, Belgium
Roger Verbeke
Affiliation:
Laboratory of Chemical Analysis of Food of Animal Origin, Veterinary Faculty of the University of Ghent, Casinoplein 24, B-9000 Ghent, Belgium
Get access Rights & Permissions [Opens in a new window]

Summary

Seven lactating goat mammary glands from 6 goats were perfused for several hours in the presence of [U-14C]L-leucine (4 experiments) or [2-3H; l-14C]DL-leucine (3 experiments) and received adequate quantities of glucose, acetate and amino acids. Radioactivity in casein was mainly recovered in leucine and 90% of casein leucine was derived from free plasma leucine. About 64% of the leucine molecules were used for casein synthesis. Up to 12% of the molecules were channelled into lipid synthesis, while the remaining (up to 24%) were metabolized to CO2. From the 3H/14C ratio of casein and casein leucine, it was calculated that 70–80% of the leucine molecules were reversibly transaminated before their incorporation into milk protein. However, only 4–8% of the plasma leucine molecules were transaminated during passage through the udder. Different pools for oxidation and for protein synthesis may be present in the goat mammary gland.

Type
Original Articles
Information
Journal of Dairy Research , Volume 50 , Issue 4 , November 1983 , pp. 413 - 424
Copyright
Copyright © Proprietors of Journal of Dairy Research 1983

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Abraham, S., Madsen, J. & Chaikoff, I. L. 1964 The influence of glucose on amino acid carbon incorporation into proteins, fatty acids and carbon dioxide by lactating rat mammary gland slices. Journal of Biologica lChemistry 239 855–864CrossRefGoogle ScholarPubMed
Annison, E. F. & Linzell, J. L. 1964 The oxidation and utilization of glucose and acetate by the mammary gland of the goat in relation to their over-all metabolism and to milk formation. Journal of Physiology 175 372–385CrossRefGoogle ScholarPubMed
Bickerstaffe, R., Annison, E. F. & Linzell, J. L. 1974 The metabolism of glucose, acetate, lipids and amino acids in lactating dairy cows. Journal of Agricultural Science 82 71–85.CrossRefGoogle Scholar
Clark, J. H., Spires, H. R. & Davis, C. L. 1978 Uptake and metabolism of nitrogenous components by the lactating mammary gland. Federation Proceedings 37 1233–1238Google Scholar
Davis, S. R., Bickerstaffe, R. & Hart, D. S. 1978 Amino acid uptake by the mammary gland of the lactating ewe. Australian Journal of Biological Sciences 31 123–132CrossRefGoogle ScholarPubMed
Davis, S. R. & Mepham, T. B. 1976 Metabolism of L-[U-14C]valine, L-[U-14C]leucine, L-[U-14C]histidine and L-[U-14C]phenylalanine by the isolated perfused lactating guinea-pig mammary gland. Biochemical Journal 156 553–560CrossRefGoogle ScholarPubMed
Dirinck, P., Veys, J., Deoloedt, M. & Schamp, N. 1980 Head-space enrichment on tenax for characterization and flavour evaluation of some tobacco types. Tobacco International 182 125–129Google Scholar
Feller, D. D. & Feist, E. 1962 The conversion of leucine carbon into CO2, fatty acids and other products by adipose tissue. Biochimica et Biophysica Acta 62 40–44CrossRefGoogle ScholarPubMed
Hardwick, D. C., Linzell, J. L. & Price, S. M. 1961 The effect of glucose and acetate on milk secretion by the perfused goat udder. Biochemical Journal 80 37–45CrossRefGoogle ScholarPubMed
Hendler, R. W. 1964 Procedure for simultaneous assay of two β-emitting isotopes with the liquid scintillation counting technique. Analytical Biochemistry 7 110–120CrossRefGoogle ScholarPubMed
Ichihara, A. 1973 Cellular differentiation and isozymes of branched-chain amino acid transaminase. Enzyme 15 210–223Google ScholarPubMed
Massart-Leën, A. M., de Pooter, H., Decloedt, M. & Schamp, N. 1981 Composition and variability of the branched-chain fatty acid fraction in the milk of goats and cows. Lipids 16 286–292.CrossRefGoogle Scholar
Massart-Leën, A. M., Florescu, S., Verbeke, R. & Peeters, G. 1970 Metabolism of [l-14C]palmitate and [1-14C]oleate by the isolated perfused mammary gland of the sheep or goat. Journal of Dairy Research 37 373–387CrossRefGoogle Scholar
Massart-Leën, A. M., Roets, E., Peeters, G. & Verbeke, R. 1983 Propionate for fatty acid synthesis by the mammary gland of the lactating goat. Journal of Dairy Science In the pressCrossRefGoogle ScholarPubMed
Mepham, T. B. 1971 Amino acid utilization by the lactating mammary gland. In Lactation pp. 297–315 (Ed. Falconer, I. R.), London: ButterworthGoogle Scholar
Mepham, T. B. 1982 Amino acid utilization by lactating mammary gland. Journal of Dairy Science 65 287–298CrossRefGoogle ScholarPubMed
Mepham, T. B. & Linzell, J. L. 1966 A quantitative assessment of the contribution of individual plasma amino acids to the synthesis of milk proteins by the goat mammary gland. Biochemical Journal 101 76–83CrossRefGoogle Scholar
Mepham, T. B., Peters, A. R. & Alexandrov, S. 1979 Effects of restriction of amino acid supply to the isolated perfused guinea-pig mammary gland. Journal of Dairy Research 46 69–73CrossRefGoogle Scholar
Odessey, R. & Goldberg, A. L. 1979 Leucine degradation in cell-free extracts of skeletal muscle. Biochemical Journal 178 475–489CrossRefGoogle ScholarPubMed
Page, M. A. & Williamson, D. H. 1972 Lactating mammary gland of the rat: a potential major site of ketone body utilization. Biochemical Journal 128 459–460CrossRefGoogle Scholar
Peeters, G., Houvenaghel, A., Roets, E., Massart-Leën, A. M., Verbeke, R., Dhondt, G. & Verschooten, F. 1979 Electromagnetic blood flow recording and balance of nutrients in the udder of lactating cows. Journal of Animal Science 48, 1143–1153CrossRefGoogle ScholarPubMed
Perry, T. L., Stedman, P. & Hansen, S. 1968 A versatile lithium buffer elution system for single column automatic amino acid chromatography. Journal of Chromatography 38 460–466CrossRefGoogle ScholarPubMed
Roets, E., Massart-Leën, A. M., Verbeke, R. & Peeters, G. 1979 a Metabolism of [U-14C; 2, 3-3H]L-valine by the isolated perfused goat udder. Journal of Dairy Research 46 47–57CrossRefGoogle ScholarPubMed
Roets, E., Verbeke, R., Massart-Leën, A. M. & Peeters, G. 1974 Metabolism of [14C]citrulline in the perfused sheep and goat udder. Biochemical Journal 144 435–446CrossRefGoogle ScholarPubMed
Roets, E., Verbeke, R., Peeters, G., Axmann, H. & Proksch, G. 1979 b Metabolism of ornithine in perfused goat udder. Journal of Dairy Science 62 259–269CrossRefGoogle ScholarPubMed
Schneible, P. A., Airhart, J. & Low, R. B. 1981 Differential compartmentation of leucine for oxidation and for protein synthesis in cultured skeletal muscle. Journal of Biological Chemistry 256 4888–4894CrossRefGoogle ScholarPubMed
Slater, T. F. 1957 A rapid method for the determination of small amounts of lactose in milk and tissue suspensions of mammary gland. Analyst 82 818–825CrossRefGoogle Scholar
Storry, J. E., Rook, J. A. F. & Hall, A. J. 1967 The effect of the amount and type of dietary fat on milk fat secretion in the cow. British Journal of Nutrition 21 425–438CrossRefGoogle ScholarPubMed
van Slyke, D. D. & Neill, J. M. 1924 The determination of gases in blood and other solutions by vacuum extraction and manometric measurement. Journal of Biological Chemistry 61 523–573CrossRefGoogle Scholar
Verbeke, R., Lauryssens, M., Peeters, G. & James, A. T. 1959 Incorporation of DL-[1-14C]leucine and [l-14C]isovaleric acid into milk constituents by the perfused cow's udder. Biochemical Journal 73 24–29CrossRefGoogle Scholar
Verbeke, R. & Peeters, G. 1965 Uptake of free plasma amino acids by the lactating cow's udder and amino acid composition of udder lymph. Biochemical Journal 94 183–189CrossRefGoogle ScholarPubMed
Verbeke, R., Peeters, G., Massart-Leën, A. M. & Cocquyt, G. 1968 Incorporation of DL-[2-14C]ornithine and DL-[5-14C]arginine in milk constituents by the isolated lactating sheep udder. Biochemical Journal 106 719–724CrossRefGoogle Scholar
Vina, J., Puertes, I. R., Saez, G. T. & Vina, J. R. 1981 Role of prolactin in amino acid uptake by the lactating mammary gland of the rat. FEBS Letters 126 250–252CrossRefGoogle ScholarPubMed
Vina, J. R. & Williamson, D. H. 1981 Effects of lactation on L-leucine metabolism in the rat. Biochemical Journal 194 941–947CrossRefGoogle ScholarPubMed
Wohlt, J. E., Clark, J. H., Derrig, R. G. & Davis, C. L. 1977 Valine, leucine and isoleucine metabolism by lactating bovine mammary tissue. Journal of Dairy Science 60 1875–1882CrossRefGoogle ScholarPubMed
Wood, H. G., Joffe, S., Gillespie, R., Hansen, R. G. & Hardenbrook, H. 1958 Lactose synthesis. IV. The synthesis of milk constituents after unilateral injection of glycerol-l,3-14C into the pudic artery. Journal of Biological Chemistry 233 1264–1270CrossRefGoogle Scholar