Effect of the route of nutrient administration on whole-body protein kinetics in man Journal Article


Authors: Jeevanandam, M.; Lowry, S. F.; Brennan, M. F.
Article Title: Effect of the route of nutrient administration on whole-body protein kinetics in man
Abstract: The kinetic mechanism resulting in nitrogen (N) retention during oral or continuous intravenous feeding (IVF) was investigated in normal subjects and hospitalized patients. The whole-body protein turnover rate (Q) in these adult subjects was estimated using a primed-constant infusion of 15N-glycine and measuring the isotope enrichments in urinary urea and ammonia. Based on a stochastic model, the total protein synthesis (S) and breakdown (C) rates were calculated from N excretion and intake. These protein kinetic responses were studied either after brief (two or three days) or extended (ten days) fasting or during the fourth day of defined formula oral feeding or the tenth to 14th day of parenteral repletion by IVF. The mean daily intake during feeding was 270 ± 7 mg N/kg and 28 ± 2 nonprotein kcal/kg. The results from a total of 120 studies are summarized. In the absence of any N intake, depleted patients with cancer demonstrated a higher Q (+ 16%), with increased S (+25%) than depleted patients without cancer or acutely depleted normals. In all groups, protein kinetics were increased to a greater extent by oral feeding, compared to IVF. All subjects are in positive N balance during feeding and the mean N retention is 32 ± 3%, which is not different among groups. Protein accretion during oral feeding is due to an increase in S and a similar decrease in C of body protein. During IVF this is achieved by a larger decrease in C with relatively little or no change in S. © 1987.
Keywords: adult; aged; aged, 80 and over; energy intake; neoplasms; proteins; models, biological; protein metabolism; food intake; kinetics; protein synthesis; intravenous administration; administration, oral; therapy; fasting; glycine; nitrogen; oral drug administration; endocrine system; middle age; food, formulated; nutritional value; parenteral nutrition, total; human; male; female; support, non-u.s. gov't; support, u.s. gov't, p.h.s.; nitrogen balance
Journal Title: Metabolism
Volume: 36
Issue: 10
ISSN: 0026-0495
Publisher: Elsevier Inc.  
Date Published: 1987-10-01
Start Page: 968
End Page: 973
Language: English
DOI: 10.1016/0026-0495(87)90134-x
PUBMED: 3116365
PROVIDER: scopus
DOI/URL:
Notes: Article -- Export Date: 5 February 2021 -- Source: Scopus
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  1. Murray F Brennan
    1059 Brennan
  2. Stephen F Lowry
    20 Lowry