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Glutamine kinetics and protein turnover in end-stage renal disease.

Abstract

Alanine and glutamine constitute the two most important nitrogen carriers released from the muscle. We studied the intracellular amino acid transport kinetics and protein turnover in nine end-stage renal disease (ESRD) patients and eight controls by use of stable isotopes of phenylalanine, alanine, and glutamine. The amino acid transport kinetics and protein turnover were calculated with a three-pool model from the amino acid concentrations and enrichment in the artery, vein, and muscle compartments. Muscle protein breakdown was more than synthesis (nmol.min(-1).100 ml leg(-1)) during hemodialysis (HD) (169.8 +/- 20.0 vs. 125.9 +/- 21.8, P < 0.05) and in controls (126.9 +/- 6.9 vs. 98.4 +/- 7.5, P < 0.05), but synthesis and catabolism were comparable pre-HD (100.7 +/- 15.7 vs. 103.4 +/- 14.8). Whole body protein catabolism decreased by 15% during HD. The intracellular appearance of alanine (399.0 +/- 47.1 vs. 243.0 +/- 34.689) and glutamine (369.7 +/- 40.6 vs. 235.6 +/- 27.5) from muscle protein breakdown increased during dialysis (nmol.min(-1).100 ml leg(-1), P < 0.01). However, the de novo synthesis of alanine (3,468.9 +/- 572.2 vs. 3,140.5 +/- 467.7) and glutamine (1,751.4 +/- 82.6 vs. 1,782.2 +/- 86.4) did not change significantly intradialysis (nmol.min(-1).100 ml leg(-1)). Branched-chain amino acid catabolism (191.8 +/- 63.4 vs. -59.1 +/- 42.9) and nonprotein glutamate disposal (347.0 +/- 46.3 vs. 222.3 +/- 43.6) increased intradialysis compared with pre-HD (nmol.min(-1).100 ml leg(-1), P < 0.01). The mRNA levels of glutamine synthase (1.45 +/- 0.14 vs. 0.33 +/- 0.08, P < 0.001) and branched-chain keto acid dehydrogenase-E2 (3.86 +/- 0.48 vs. 2.14 +/- 0.27, P < 0.05) in the muscle increased during HD. Thus intracellular concentrations of alanine and glutamine are maintained during HD by augmented release of the amino acids from muscle protein catabolism. Although muscle protein breakdown increased intradialysis, the whole body protein catabolism decreased, suggesting central utilization of amino acids released from skeletal muscle.

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  • Authors+Show Affiliations

    ,

    Division of Nephrology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131-5271, USA. draj@salud.unm.edu

    , , , ,

    Source

    MeSH

    Adult
    Alanine
    Arteries
    Diabetes Mellitus, Type 2
    Female
    Glutamic Acid
    Humans
    Kidney Failure, Chronic
    Male
    Middle Aged
    Models, Biological
    Muscle, Skeletal
    Phenylalanine
    Proteins
    Renal Dialysis
    Veins

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't
    Research Support, U.S. Gov't, P.H.S.

    Language

    eng

    PubMed ID

    15265763

    Citation

    Raj, Dominic S C., et al. "Glutamine Kinetics and Protein Turnover in End-stage Renal Disease." American Journal of Physiology. Endocrinology and Metabolism, vol. 288, no. 1, 2005, pp. E37-46.
    Raj DS, Welbourne T, Dominic EA, et al. Glutamine kinetics and protein turnover in end-stage renal disease. Am J Physiol Endocrinol Metab. 2005;288(1):E37-46.
    Raj, D. S., Welbourne, T., Dominic, E. A., Waters, D., Wolfe, R., & Ferrando, A. (2005). Glutamine kinetics and protein turnover in end-stage renal disease. American Journal of Physiology. Endocrinology and Metabolism, 288(1), pp. E37-46.
    Raj DS, et al. Glutamine Kinetics and Protein Turnover in End-stage Renal Disease. Am J Physiol Endocrinol Metab. 2005;288(1):E37-46. PubMed PMID: 15265763.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Glutamine kinetics and protein turnover in end-stage renal disease. AU - Raj,Dominic S C, AU - Welbourne,Tomas, AU - Dominic,Elizabeth A, AU - Waters,Debra, AU - Wolfe,Robert, AU - Ferrando,Arny, Y1 - 2004/07/20/ PY - 2004/7/22/pubmed PY - 2005/3/3/medline PY - 2004/7/22/entrez SP - E37 EP - 46 JF - American journal of physiology. Endocrinology and metabolism JO - Am. J. Physiol. Endocrinol. Metab. VL - 288 IS - 1 N2 - Alanine and glutamine constitute the two most important nitrogen carriers released from the muscle. We studied the intracellular amino acid transport kinetics and protein turnover in nine end-stage renal disease (ESRD) patients and eight controls by use of stable isotopes of phenylalanine, alanine, and glutamine. The amino acid transport kinetics and protein turnover were calculated with a three-pool model from the amino acid concentrations and enrichment in the artery, vein, and muscle compartments. Muscle protein breakdown was more than synthesis (nmol.min(-1).100 ml leg(-1)) during hemodialysis (HD) (169.8 +/- 20.0 vs. 125.9 +/- 21.8, P < 0.05) and in controls (126.9 +/- 6.9 vs. 98.4 +/- 7.5, P < 0.05), but synthesis and catabolism were comparable pre-HD (100.7 +/- 15.7 vs. 103.4 +/- 14.8). Whole body protein catabolism decreased by 15% during HD. The intracellular appearance of alanine (399.0 +/- 47.1 vs. 243.0 +/- 34.689) and glutamine (369.7 +/- 40.6 vs. 235.6 +/- 27.5) from muscle protein breakdown increased during dialysis (nmol.min(-1).100 ml leg(-1), P < 0.01). However, the de novo synthesis of alanine (3,468.9 +/- 572.2 vs. 3,140.5 +/- 467.7) and glutamine (1,751.4 +/- 82.6 vs. 1,782.2 +/- 86.4) did not change significantly intradialysis (nmol.min(-1).100 ml leg(-1)). Branched-chain amino acid catabolism (191.8 +/- 63.4 vs. -59.1 +/- 42.9) and nonprotein glutamate disposal (347.0 +/- 46.3 vs. 222.3 +/- 43.6) increased intradialysis compared with pre-HD (nmol.min(-1).100 ml leg(-1), P < 0.01). The mRNA levels of glutamine synthase (1.45 +/- 0.14 vs. 0.33 +/- 0.08, P < 0.001) and branched-chain keto acid dehydrogenase-E2 (3.86 +/- 0.48 vs. 2.14 +/- 0.27, P < 0.05) in the muscle increased during HD. Thus intracellular concentrations of alanine and glutamine are maintained during HD by augmented release of the amino acids from muscle protein catabolism. Although muscle protein breakdown increased intradialysis, the whole body protein catabolism decreased, suggesting central utilization of amino acids released from skeletal muscle. SN - 0193-1849 UR - https://www.unboundmedicine.com/medline/citation/15265763/Glutamine_kinetics_and_protein_turnover_in_end_stage_renal_disease_ L2 - http://www.physiology.org/doi/full/10.1152/ajpendo.00240.2004?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -