Oral L-glutamine pretreatment attenuates skeletal muscle atrophy induced by 24-h fasting in mice.

Abstract

L-Glutamine (L-Gln) supplementation has been pointed out as an anticatabolic intervention, but its effects on protein synthesis and degradation signaling in skeketal muscle are still poorly known. The effects of L-Gln pretreatment (1 g kg-1 day-1 body weight for 10 days) on muscle fiber cross-sectional area (CSA), amino acid composition (measured by LC-MS/MS) and protein synthesis (Akt-mTOR) and degradation (ubiquitin ligases) signaling in soleus and extensor digitorum longus (EDL) muscles in 24-h-fasted mice were investigated. The fiber CSA of EDL muscle was not different between the L-Gln-fasted and L-Gln-fed groups. This finding was associated with reduced contents of L-Leu and L-Iso and activation of protein synthesis signaling (p-RPS6Ser240/244 and Akt-mTOR). The spectrum of soleus muscle fiber CSA distribution was larger in L-Gln-fasted as compared with placebo-fasted mice. This effect of L-Gln pretreatment was associated with changes in red fibers L-Gln metabolism as indicated by increased intracellular L-glutamine/L-glutamate ratio, L-aspartate and GABA levels. L-Gln supplementation reduced fasting-induced mass loss in tibialis anterior and gastrocnemius muscles. Evidence is presented that pretreatment with L-glutamine attenuates skeletal muscle atrophy induced by 24-h fasting through mechanisms that vary with the muscle fiber type.

• Authors: Diogo Antonio Alves de Vasconcelos, Pieter Giesbertz, Diego Ribeiro de Souza, Kaio Fernando Vitzel, Phablo Abreu, Gabriel Nasri Marzuca-Nassr, Marco Aurélio Salomão Fortes, Gilson Masahiro Murata, Sandro Massao Hirabara, Rui Curi, Hannelore Daniel, Tania Cristina Pithon-Curi
• Journal: The Journal of nutritional biochemistry (J Nutr Biochem) Vol. 70 Pg. 202-214 (08 2019) ISSN: 1873-4847 [Electronic] United States
• PMID: 31233980 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2019 Elsevier Inc. All rights reserved.

Chemical References

• Adaptor Proteins, Signal Transducing
• Cell Cycle Proteins
• Eif4ebp1 protein, mouse
• Ribosomal Protein S6
• ribosomal protein S6, mouse
• Glutamine
• gamma-Aminobutyric Acid

Topics

• Adaptor Proteins, Signal Transducing (metabolism)
• Adipose Tissue (metabolism)
• Administration, Oral
• Animals
• Cell Cycle Proteins (metabolism)
• Fasting (adverse effects)
• Glutamine (administration & dosage)
• Male
• Mice
• Mice, Inbred C57BL
• Muscle, Skeletal (pathology)
• Muscular Atrophy (prevention & control)
• Ribosomal Protein S6 (metabolism)
• Signal Transduction
• gamma-Aminobutyric Acid (metabolism)