Interpretation of tracer studies of amino acid kinetics in the fed state is dependent on knowledge of splanchnic uptake of diet-derived amino acids. We studied five healthy control children and five children with cystic fibrosis (CF). After an overnight fast, the children ingested, hourly, a formula diet for 11 h. 5,5,5-[2H3]Leucine was added to the feedings during the last 6 h, and an i.v. infusion of 1-[13C]leucine was administered during the last 2 h of the formula feeding. The mean rate of splanchnic uptake of leucine was similar in the CF and control group, 23.8 +/- 24.0 and 21.5 +/- 21.2 mumol.kg-1.h-1, respectively. Fractional splanchnic uptake of leucine was not significantly different in the patients with CF (0.16 +/- 0.112 mean +/- SD) compared with the control children (0.244 +/- 0.256(-1)). The rate of whole body protein breakdown was not significantly different between the groups (CF versus control) with (159 +/- 18 versus 135 +/- 28 mumol.kg-1.h-1) or without (135 +/- 14 versus 114 +/- 20 mumol.kg-1.h-1) correction for splanchnic leucine uptake. However, for the 10 cases combined, protein breakdown corrected for splanchnic leucine uptake (147 +/- 26 mumol.kg-1.h-1) was 18% greater than uncorrected protein breakdown (124 +/- 20 mumol.kg-1.h-1) (p = 0.009). The data suggest that companion studies of splanchnic uptake might enhance the interpretation of leucine kinetics in the fed state.
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http://dx.doi.org/10.1203/00006450-199905010-00012 | DOI Listing |
Physiol Rep
January 2025
Center for Translational Research in Aging and Longevity, Department of Health and Kinesiology, Texas A&M University, College Station, Texas, USA.
Sepsis leads to an acute breakdown of muscle to support increased caloric and amino acid requirements. Little is known about the role of adipose and muscle tissue breakdown and intestinal metabolism in glucose substrate supply during the acute phase of sepsis. In a translational porcine model of sepsis, we explored the across organ net fluxes of gluconeogenic substrates.
View Article and Find Full Text PDFPhysiol Rep
September 2024
Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
Am J Physiol Gastrointest Liver Physiol
September 2024
Center for Translational Research in Aging & Longevity. Department of Health & Kinesiology, Texas A&M University, College Station, TX, United States.
Human sepsis is characterized by increased protein breakdown and changes in arginine and citrulline metabolism. However, it is unclear whether this is caused by changes in transorgan metabolism. We therefore studied in a induced pig sepsis model the changes in protein and arginine related metabolism on whole body (Wb) and transorgan level.
View Article and Find Full Text PDFJ Lipid Res
October 2024
Department of Surgery, University of California Davis School of Medicine, Sacramento, California, USA; Center for Alimentary and Metabolic Science, University of California Davis School of Medicine, Sacramento, California, USA. Electronic address:
Microbe-produced molecules (xenometabolites) found in foods or produced by gut microbiota are increasingly implicated in microbe-microbe and microbe-host communication. Xenolipids, in particular, are a class of metabolites for which the full catalog remains to be elaborated in mammalian systems. We and others have observed that cis-3,4-methylene-heptanoylcarnitine is a lipid derivative that is one of the most abundant medium-chain acylcarnitines in human blood, hypothesized to be a product of incomplete β-oxidation of one or more "odd-chain" long-chain cyclopropane fatty acids (CpFAs).
View Article and Find Full Text PDFCurr Opin Clin Nutr Metab Care
September 2024
Centre of Metabolism, Ageing and Physiology, University of Nottingham, Royal Derby Hospital Medical School, Derby, UK.
Purpose Of Review: Dietary proteins are broken down into peptides across the gastrointestinal tract, with skeletal muscle being a primary deposition site for amino acids in the form of incorporation into, for example, metabolic and structural proteins. It follows that key research questions remain as to the role of amino acid bioavailability, of which protein digestibility and splanchnic sequestration (absorption and utilization) of amino acids are determining factors, impact upon muscle protein synthesis (MPS) in clinical states.
Recent Findings: Elevated splanchnic amino acid uptake has been implicated in anabolic resistance (i.
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