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Decreased rate of protein synthesis, caspase-3 activity, and ubiquitin-proteasome proteolysis in soleus muscles from growing rats fed a low-protein, high-carbohydrate diet.
Can J Physiol Pharmacol ; 92(6): 445-54, 2014 Jun.
Article em En | MEDLINE | ID: mdl-24826789
The aim of this study was to investigate the changes in the rates of both protein synthesis and breakdown, and the activation of intracellular effectors that control these processes in soleus muscles from growing rats fed a low-protein, high-carbohydrate (LPHC) diet for 15 days. The mass and the protein content, as well as the rate of protein synthesis, were decreased in the soleus from LPHC-fed rats. The availability of amino acids was diminished, since the levels of various essential amino acids were decreased in the plasma of LPHC-fed rats. Overall rate of proteolysis was also decreased, explained by reductions in the mRNA levels of atrogin-1 and MuRF-1, ubiquitin conjugates, proteasome activity, and in the activity of caspase-3. Soleus muscles from LPHC-fed rats showed increased insulin sensitivity, with increased levels of insulin receptor and phosphorylation levels of AKT, which probably explains the inhibition of both the caspase-3 activity and the ubiquitin-proteasome system. The fall of muscle proteolysis seems to represent an adaptive response that contributes to spare proteins in a condition of diminished availability of dietary amino acids. Furthermore, the decreased rate of protein synthesis may be the driving factor to the lower muscle mass gain in growing rats fed the LPHC diet.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Biossíntese de Proteínas / Carboidratos da Dieta / Músculo Esquelético / Dieta com Restrição de Proteínas / Ubiquitina / Complexo de Endopeptidases do Proteassoma / Caspase 3 / Proteólise Limite: Animals Idioma: En Revista: Can J Physiol Pharmacol Ano de publicação: 2014 Tipo de documento: Article País de afiliação: Brasil País de publicação: Canadá

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Biossíntese de Proteínas / Carboidratos da Dieta / Músculo Esquelético / Dieta com Restrição de Proteínas / Ubiquitina / Complexo de Endopeptidases do Proteassoma / Caspase 3 / Proteólise Limite: Animals Idioma: En Revista: Can J Physiol Pharmacol Ano de publicação: 2014 Tipo de documento: Article País de afiliação: Brasil País de publicação: Canadá