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Open AccessPrematurity blunts protein synthesis in skeletal muscle independently of body weight in neonatal pigs
Postnatal growth failure in premature infants is associated with reduced lean mass accretion. Prematurity impairs the feeding-induced stimulation of translation initiation and protein synthesis in the skeletal...
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Article
Preterm birth alters the feeding-induced activation of Akt signaling in the muscle of neonatal piglets
Postnatal lean mass accretion is commonly reduced in preterm infants. This study investigated mechanisms involved in the blunted feeding-induced activation of Akt in the skeletal muscle of preterm pigs that co...
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Article
Intermittent leucine pulses during continuous feeding alters novel components involved in skeletal muscle growth of neonatal pigs
When neonatal pigs continuously fed formula are supplemented with leucine pulses, muscle protein synthesis and body weight gain are enhanced. To identify the responsible mechanisms, we combined plasma metabolo...
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Article
Short- and long-term effects of leucine and branched-chain amino acid supplementation of a protein- and energy-reduced diet on muscle protein metabolism in neonatal pigs
The objective of this study was to determine if enteral leucine or branched-chain amino acid (BCAA) supplementation increases muscle protein synthesis in neonates who consume less than their protein and energy...
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Article
Insulin modulates energy and substrate sensing and protein catabolism induced by chronic peritonitis in skeletal muscle of neonatal pigs
Acute infection promotes skeletal muscle wasting and insulin resistance, but the effect of insulin on energy and substrate sensing in skeletal muscle of chronically infected neonates has not been studied.
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Article
Amino acids, independent of insulin, attenuate skeletal muscle autophagy in neonatal pigs during endotoxemia
Sepsis induces loss of skeletal muscle mass by activating the ubiquitin proteasome (UPS) and autophagy systems. Although muscle protein synthesis in healthy neonatal piglets is responsive to amino acids (AA) s...
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Article
Leucine supplementation of a chronically restricted protein and energy diet enhances mTOR pathway activation but not muscle protein synthesis in neonatal pigs
Suboptimal nutrient intake represents a limiting factor for growth and long-term survival of low-birth weight infants. The objective of this study was to determine if in neonates who can consume only 70 % of t...
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Article
Open AccessRegulation of protein degradation pathways by amino acids and insulin in skeletal muscle of neonatal pigs
The rapid gain in lean mass in neonates requires greater rates of protein synthesis than degradation. We previously delineated the molecular mechanisms by which insulin and amino acids, especially leucine, mod...
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Article
Abundance of amino acid transporters involved in mTORC1 activation in skeletal muscle of neonatal pigs is developmentally regulated
Previously we demonstrated that the insulin- and amino acid-induced activation of the mammalian target of rapamycin complex 1 (mTORC1) is developmentally regulated in neonatal pigs. Recent studies have indicat...
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Article
Viscera and muscle protein synthesis in neonatal pigs is increased more by intermittent bolus than by continuous feeding
Continuous and intermittent bolus orogastric feedings are strategies used in infants unable to tolerate normal feeds.
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Article
Enteral leucine supplementation increases protein synthesis in skeletal and cardiac muscles and visceral tissues of neonatal pigs through mTORC1-dependent pathways
Leucine (Leu) activates mammalian target of rapamycin (mTOR) to upregulate protein synthesis (PS).
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Article
Open AccessDifferential regulation of protein synthesis in skeletal muscle and liver of neonatal pigs by leucine through an mTORC1-dependent pathway
Neonatal growth is characterized by a high protein synthesis rate that is largely due to an enhanced sensitivity to the postprandial rise in insulin and amino acids, especially leucine. The mechanism of leucin...
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Article
Differential Regulation of Protein Synthesis and mTOR Signaling in Skeletal Muscle and Visceral Tissues of Neonatal Pigs After a Meal
Protein synthesis (PS) increases after a meal in neonates, but the time course of the changes in PS in different tissues after a meal is unknown. We aimed to evaluate the changes in tissue PS, mammalian target...
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Article
Sepsis and Development Impede Muscle Protein Synthesis in Neonatal Pigs by Different Ribosomal Mechanisms
In muscle, sepsis reduces protein synthesis (MPS) by restraining translation in neonates and adults. Even though protein accretion decreases with development as neonatal MPS rapidly declines by maturation, the...
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Article
Differential effects of long-term leucine infusion on tissue protein synthesis in neonatal pigs
Leucine is unique among the amino acids in its ability to promote protein synthesis by activating translation initiation via the mammalian target of rapamycin (mTOR) pathway. Previously, we showed that leucine...
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Article
Differential regulation of protein synthesis by amino acids and insulin in peripheral and visceral tissues of neonatal pigs
The high efficiency of protein deposition during the neonatal period is driven by high rates of protein synthesis, which are maximally stimulated after feeding. In the current study, we examined the individual...
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Article
Insulin Signaling in Skeletal Muscle and Liver of Neonatal Pigs During Endotoxemia
Sepsis has been associated with tumor necrosis factor α (TNF-α) and nitric oxide (NO) overproduction, insulin resistance, and a profound suppression of muscle protein synthesis. However, lesser suppression of ...
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Article
Expression of the TGF-β Family of Ligands Is Developmentally Regulated in Skeletal Muscle of Neonatal Rats
To dissect the possible role of the transforming growth factor-β (TGF-β) family in the regulation of skeletal muscle growth during the early postnatal period, the protein abundances of the TGF-β family and the...
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Article
Developmental Regulation of Protein Kinase B Activation Is Isoform Specific in Skeletal Muscle of Neonatal Pigs
The postprandial activation of the insulin signaling pathway that leads to translation initiation is enhanced in skeletal muscle of the neonate and decreases with development in parallel with the developmental...
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Article
Regulation of Muscle Protein Synthesis in Neonatal Pigs During Prolonged Endotoxemia
In adults, protein synthesis in skeletal muscle is reduced by as much as 50% after a septic challenge, and is associated with repression of translation initiation. Neonates are highly anabolic and their muscle...
