Cited by 157Muscle metabolism and nutritionAmino Acid Enzymes and MetabolismClinical Nutrition and Gastroenterology

Effect of Infused Branched-Chain Amino Acids on Muscle and Whole-Body Amino Acid Metabolism in Man

Louard, Rita J., Barrett, Eugene J., Gelfand, Robert A.·1990·Clinical Science

Abstract

1. Using the forearm balance method, together with systemic infusions of l-[ring-2,6-3H]phenylalanine and l-[1-14C]leucine, we examined the effects of infused branched-chain amino acids on whole-body and skeletal muscle amino acid kinetics in 10 postabsorptive normal subjects; 10 control subjects received only saline. 2. Infusion of branched-chain amino acids caused a four-fold rise in arterial branched-chain amino acid levels and a two-fold rise in branched-chain keto acids; significant declines were observed in circulating levels of most other amino acids, including phenylalanine, which fell by 34%. Plasma insulin levels were unchanged from basal levels (8 ± 1 μ-units/ml). 3. Whole-body phenylalanine flux, an index of proteolysis, was significantly suppressed by branched-chain amino acid infusion (P < 0.002), and forearm phenylalanine production was also inhibited (P < 0.03). With branched-chain amino acid infusion total leucine flux rose, with marked increments in both oxidative and non-oxidative leucine disposal (P < 0.001). Proteolysis, as measured by endogenous leucine production, showed a modest 12% decrease, although this was not significant when compared with saline controls. The net forearm balance of leucine and other branched-chain amino acids changed from a basal net output to a marked net uptake (P < 0.001) during branched-chain amino acid infusion, with significant stimulation of local leucine disposal. Despite the rise in whole-body non-oxidative leucine disposal, and in forearm leucine uptake and disposal, forearm phenylalanine disposal, an index of muscle protein synthesis, was not stimulated by infusion of branched-chain amino acids. 4. The results suggest that in normal man branched-chain amino acid infusion suppresses skeletal muscle proteolysis independently of any rise of plasma insulin. Muscle branched-chain amino acid uptake rose dramatically in the absence of any apparent increase in muscle protein synthesis, as measured by phenylalanine disposal, or in branched-chain keto acid release. Thus, an increase in muscle branched-chain amino acid concentrations and/ or local branched-chain amino acid oxidation must account for the increased disposal of branched-chain amino acids.

Integrity signals

Registry

Crossref · 10.1042/cs0790457

Cites

18 of 18 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

This paper’s full text isn’t openly available, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Louard, R. J., Barrett, E. J., & Gelfand, R. A.
Affiliations
Yale University (US)
Venue
Clinical Science
Published
1990-11-01
Volume
79
Issue
5
Pages
457-466
ISSN
  • 0143-5221 (ISSN-L)
  • 1470-8736
OpenAlex
W14752674
Cited by
157
References
18
Citations by year
2025: 1 · 2024: 2 · 2023: 5 · 2022: 8 · 2021: 7 · 2020: 5 · 2019: 3 · 2018: 4 · 2017: 5 · 2016: 6 · 2015: 6 · 2014: 5 · 2013: 5 · 2012: 3
FWCI
2.60
Type
journal article
Language
en
Open access
closed
Locations
  • Clinical Science (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health (5t32dk007476-15)
  • U.S. Public Health Service
  • National Institute of Diabetes and Digestive and Kidney Diseases (DK 38578, R01DK038578, DK07476)
  • National Center for Research Resources (RR 125)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Biochemistry › Amino Acid Enzymes and Metabolism
  • Health Sciences › Nursing › Nutrition and Dietetics › Clinical Nutrition and Gastroenterology
Keywords
branched-chain amino acids, amino acid metabolism, skeletal muscle proteolysis, muscle protein synthesis, leucine flux, amino acid kinetics, branched-chain keto acids
MeSH terms
Adolescent, Adult, Amino Acids, Branched-Chain, Female, Forearm, Humans, Infusions, Intravenous, Insulin, Kinetics, Leucine, Male, Muscle Proteins, Muscles, Phenylalanine

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review