Repositorio
Institucional

Gorjao, Renata

Rodrigues Jr, Carlos Flores

Murata, Gilson Masahiro

Gerlinger-Romero, Frederico

Nachbar, Renato Tadeu

Marzuca-Nassr, Gabriel Nasri

Vitzel, Kaio Fernando

Hirabara, Sandro Massao

Pithon-Curi, Tania Cristina

Curi, Rui

Changes in Skeletal Muscle Protein Metabolism Signaling Induced by Glutamine Supplementation and Exercise

MDPI

NUTRIENTS

en

Aim: To evaluate the effects of resistance exercise training (RET) and/or glutamine supplementation (GS) on signaling protein synthesis in adult rat skeletal muscles. Methods: The following groups were studied: (1) control, no exercise (C), (2) exercise, hypertrophy resistance exercise training protocol (T), (3) no exercise, supplemented with glutamine (G), and (4) exercise and supplemented with glutamine (GT). The rats performed hypertrophic training, climbing a vertical ladder with a height of 1.1 m at an 80 degrees incline relative to the horizontal with extra weights tied to their tails. The RET was performed three days a week for five weeks. Each training session consisted of six ladder climbs. The extra weight load was progressively increased for each animal during each training session. The G groups received daily L-glutamine by gavage (one g per kilogram of body weight per day) for five weeks. The C group received the same volume of water during the same period. The rats were euthanized, and the extensor digitorum longus (EDL) muscles from both hind limbs were removed and immediately weighed. Glutamine and glutamate concentrations were measured, and histological, signaling protein contents, and mRNA expression analyses were performed. Results: Supplementation with free L-glutamine increased the glutamine concentration in the EDL muscle in the C group. The glutamate concentration was augmented in the EDL muscles from T rats. The EDL muscle mass did not change, but a significant rise was reported in the cross-sectional area (CSA) of the fibers in the three experimental groups. The levels of the phosphorylated proteins (pAkt/Akt, pp70S6K/p70S6K, p4E-BP1/4E-BP1, and pS6/S6 ratios) were significantly increased in EDL muscles of G rats, and the activation of p4E-BP1 was present in T rats. The fiber CSAs of the EDL muscles in T, G, and GT rats were increased compared to the C group. These changes were accompanied by a reduction in the 26 proteasome activity of EDL muscles from T rats. Conclusion: Five weeks of GS and/or RET induced muscle hypertrophy, as indicated by the increased CSAs of the EDL muscle fibers. The increase in CSA was mediated via the upregulated phosphorylation of Akt, 4E-BP1, p70S6k, and S6 in G animals and 4E-BP1 in T animals. In the EDL muscles from T animals, a decrease in proteasome activity, favoring a further increase in the CSA of the muscle fibers, was reported.

2023

artículo original

Acceso abierto

10.3390/nu15224711

PDF

physical exercise

hypertrophy

pS6

proteasome

4E-BP-1

26S proteasome

Nutrición y Dietética

ejercicio físico

hipertrofia

pS6

proteosoma

4E-BP-1

proteosoma 26S

artículo original

versión publicada

CC BY 4.0

CC BY 4.0

acceso abierto

acceso abierto

WOS:001113731800001

verde# dorado

Nutrición y Dietética

FAPESP 2018/09868-7

CIES RED211993