The Metabolic Fate of Leucine in Muscle and Adipose Tissue of Sheep

Wijayasinghe, M. S.; Thompson, James R.; Milligan, L. P.

doi:10.4141/cjas84-262

Cited by 4 publications

(1 citation statement)

References 5 publications

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“…Leucine is also used for protein synthesis and for lipid incorporation, although at a lower rate. Our results are in agreement with previous results that demonstrated that leucine is a deficient precursor of fatty acids and sterols in adipose tissue of sheep, rats, and mice [Feller and Feist, ; Rosenthal et al, ; Wijayasinghe et al, ; Vernon et al, ]. Although, further studies are needed to evaluate whether hormones or other metabolites are capable of modifying BCAA metabolic fate in primary adipocytes, our work establishes a basis for these further studies.…”

Section: Discussionsupporting

confidence: 93%

Metabolic Fate of Branched‐Chain Amino Acids During Adipogenesis, in Adipocytes From Obese Mice and C2C12 Myotubes

Estrada-Alcalde

Tenorio-Guzman

Tovar

et al. 2016

J of Cellular Biochemistry

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Branched-chain amino acid (BCAA) catabolism is regulated by the branched-chain aminotransferase (BCAT2) and the branched-chain α-keto acid dehydrogenase complex (BCKDH). BCAT2 and BCKDH expression and activity are modified during adipogenesis and altered in adipose tissues of mice with genetic or diet-induced obesity. However, little is known about how these modifications and alterations affect the intracellular metabolic fate of BCAAs during adipogenesis, in adipocytes from mice fed a control or high-fat diet or in C2C12 myotubes. Here, we demonstrate that BCAAs are mainly incorporated into proteins during the early stages of adipocyte differentiation. However, they are oxidized and incorporated into lipids during the late days of differentiation. Conversely, 92% and 97% of BCAA were oxidized, 1.6% and 6% were used for protein synthesis and 1.2% and 1.5% were incorporated into lipids in adipocytes from epididymal and subcutaneous adipose tissue, respectively. All three pathways were decreased in adipocytes from mice fed a high-fat diet. In C2C12 myotubes, leucine is mainly used for protein synthesis and palmitate is incorporated into lipids. Interestingly, leucine decreased both palmitate oxidation and its incorporation to lipids and proteins; and palmitate increased leucine oxidation and decreased its incorporation to lipids and proteins in a dose-dependent manner. These results demonstrate that BCAA metabolic fate differs between the early and late stages of adipocyte differentiation and in adipocytes from mice fed a control or high-fat diet; and that leucine affects the metabolic fate of palmitate and vice versa in C2C12 myotubes. J. Cell. Biochem. 118: 808-818, 2017. © 2016 Wiley Periodicals, Inc.

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Section: Discussionsupporting

confidence: 93%

Metabolic Fate of Branched‐Chain Amino Acids During Adipogenesis, in Adipocytes From Obese Mice and C2C12 Myotubes

Estrada-Alcalde

Tenorio-Guzman

Tovar

et al. 2016

J of Cellular Biochemistry

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Fatty acid synthesis from amino acids in sheep adipose tissue

Vernon

Finley

Taylor

1985

Comparative Biochemistry and Physiology Part B: Comparative Bio

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Estimation of tissue protein synthesis in sheep during sustained elevation of plasma leucine concentration by intravenous infusion

Schaefer¹,

Davis²,

Hughson³

1986

Br J Nutr

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I . The fractional rate of protein synthesis (FSR) was determined in skeletal muscle, liver, rumen and cardiac muscle of wether sheep by continuous intravenous infusion of ~-[4,5-~H]leucine accompanied by infusion of 0, 7.6, 15.2 or 22.8 mmol leucine/h (three sheep per treatment). FSR was calculated assuming plasma (ks,) or intracellular (ksi) leucine-specific radioactivity (SRA) was representative of the leucine precursor pool SRA for protein synthesis.2. Plasma leucine concentration (plateau) was linearly related to leucine infusion rate, 22.8 mmol/h evoking a tenfold increase in plasma concentration.3. Difference between plasma leucine SRA and intracellular leucine SRA in all tissues diminished as plasma leucine concentration increased. 4.There were significant differences between kSt and k,, estimates for liver and rumen in control sheep. 5. As leucine infusion rate increased, differences between kSi and k,, diminished in all tissues. With increasing leucine infusion, in liver k,, decreased and k,, was increased, in rumen kSi decreased and k,, was stable, while in cardiac and skeletal muscle k,9i and k,, both increased.6 . At a leucine infusion rate of 22.8 mmol/h, mean k,, and k,qi respectively were: rumen 1 1 (SE 2), 13 (SE 1); liver 19 (SE 2), 21 (SE 2); cardiac muscle 3-6 (SE 0.4), 3.8 (SE 0.3); skeletal muscle 4.1 (SE 0.2), 4.5 (SE 0.5) and did not differ significantly in any tissue.

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The Metabolic Fate of Leucine in Muscle and Adipose Tissue of Sheep

Cited by 4 publications

References 5 publications

Metabolic Fate of Branched‐Chain Amino Acids During Adipogenesis, in Adipocytes From Obese Mice and C2C12 Myotubes

Metabolic Fate of Branched‐Chain Amino Acids During Adipogenesis, in Adipocytes From Obese Mice and C2C12 Myotubes

Fatty acid synthesis from amino acids in sheep adipose tissue

Estimation of tissue protein synthesis in sheep during sustained elevation of plasma leucine concentration by intravenous infusion

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