Leucine Supplementation in a Chronically Protein-Restricted Diet Enhances Muscle Weight and Postprandial Protein Synthesis of Skeletal Muscle by Promoting the mTOR Pathway in Adult Rats
| Autor: | Shiyan Qiao, Xiangfang Zeng, Hong Liu, Chunyuan Xie, Licui Chu, Bo Zhang |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
medicine.medical_specialty Environmental Engineering Low protein General Computer Science Growth performance Materials Science (miscellaneous) General Chemical Engineering medicine.medical_treatment Energy Engineering and Power Technology P70-S6 Kinase 1 Low-protein diet 03 medical and health sciences Leucine Valine Internal medicine Casein medicine 030109 nutrition & dietetics Chemistry General Engineering Skeletal muscle Eukaryotic initiation factor 4E binding Adult rats 030104 developmental biology Endocrinology medicine.anatomical_structure Biochemistry lcsh:TA1-2040 Muscle weight Protein synthesis lcsh:Engineering (General). Civil engineering (General) |
| Zdroj: | Engineering, Vol 3, Iss 5, Pp 760-765 (2017) |
| ISSN: | 2095-8099 |
| DOI: | 10.1016/j.eng.2017.03.008 |
| Popis: | Low protein intake causes a decrease in protein deposition in most animal tissues. The purpose of this study was to investigate whether leucine supplementation would increase the synthesis rate of protein and muscle weight in adult rats, which chronically consume only 58.8% of their protein requirements. Thirty-six male Sprague-Dawley rats were assigned to one of three dietary treatments including a 20% casein diet (CON), a 10% casein + 0.44% alanine diet (R), and a 10% casein + 0.87% leucine diet (RL). After a 10 d dietary treatment, plasma amino acid levels were measured after feeding, the gastrocnemius muscles and soleus muscles were harvested and weighed, and the fractional synthesis rate (FSR) and mammalian target of rapamycin (mTOR) signaling proteins in skeletal muscle were measured. Regarding the plasma amino acid level, the RL group had the highest concentration of leucine (P < 0.05) and the lowest concentration of isoleucine (P < 0.05) among the three groups, and the CON group had a lower concentration of valine (P < 0.05) than the R and RL groups. Compared with the R and RL groups, the CON group diet significantly increased (P < 0.05) feed intake, protein synthesis rate, and the phosphorylation of eukaryotic initiation factor 4E binding protein 1 (4E-BP1), and decreased the weight of abdominal adipose. Compared with the R group, the RL group significantly increased in gastrocnemius muscle weight, protein synthesis rate, and phosphorylation of both ribosomal protein S6 kinase 1 (S6K1) and 4E-BP1. In conclusion, when protein is chronically restricted in adult rat diets, leucine supplementation moderately improves body weight gain and increases muscle protein synthesis through mTOR activation. |
| Databáze: | OpenAIRE |
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