Author:
Mao Xiangbing,Zeng Xiangfang,Huang Zhimin,Wang Junjun,Qiao Shiyan
Abstract
Leucine and leptin play important roles in regulating protein synthesis and degradation in skeletal musclesin vitroandin vivo.However, the objective of the present study was to determine whether leptin and leucine function synergistically in regulating protein metabolism of skeletal muscles. In thein vitroexperiment, C2C12 myotubes were cultured for 2 h in the presence of 5 mm-leucine and/or 50 ng/ml of leptin. In thein vivoexperiment, C57BL/6 andob/obmice were randomly assigned to be fed a non-purified diet supplemented with 3 %l-leucine or 2·04 %l-alanine (isonitrogenous control) for 14 d.Ob/obmice were injected intraperitoneally with sterile PBS or recombinant mouse leptin (0·1 μg/g body weight) for 14 d. In C57BL/6 mice, dietary leucine supplementation increased (P< 0·05) plasma leptin, leptin receptor expression and protein synthesis in skeletal muscles, but reduced (P< 0·05) plasma urea and protein degradation in skeletal muscles. Dietary leucine supplementation and leptin injection increased the relative weight of the gastrocnemius and soleus muscles inob/obmice. Moreover, leucine and leptin treatments stimulated (P< 0·05) protein synthesis and inhibited (P< 0·05) protein degradation in C2C12 myotubes and skeletal muscles ofob/obmice. There were interactions (P< 0·05) between the leucine and leptin treatments with regard to protein metabolism in C2C12 myotubes and soleus muscles ofob/obmice but not in the gastrocnemius muscles ofob/obmice. Collectively, these results suggest that leptin and leucine synergistically regulate protein metabolism in skeletal muscles bothin vitroandin vivo.
Publisher
Cambridge University Press (CUP)
Subject
Nutrition and Dietetics,Medicine (miscellaneous)
Cited by
25 articles.
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