Glucocorticoids retard skeletal muscle development and myoblast protein synthesis through a mechanistic target of @entity3446 ( XXXX )-signaling pathway in broilers ( @entity1573 ).

@entity2085 @entity368 @entity3446 @entity3470 @entity1573 @entity619 @entity1017 @entity8582
UNASSIGNED: Glucocorticoids exert a well-known catabolic protein action on skeletal muscle. The mechanistic target of @entity3446 ( @entity3470 ) signaling pathway acts as a central regulator of protein metabolism. Whether glucocorticoids regulate protein synthesis through the @entity3470 pathway in skeletal muscle of @entity1573 remains unknown. This study was performed to characterize the effect of glucocorticoids on the @entity3470 pathway in skeletal muscle development in @entity1573 , and on protein synthesis in cultured @entity2085 . Male 29-d-old @entity1573 were given a @entity619 injection (2   mg/kg) twice per day for 4   d (n   =   16). @entity1573 @entity2085 were exposed to @entity619 for 24   h (100     mol/L, n   =   4 cultures). The interaction between @entity619 and @entity368 was also investigated. ANOVA and Duncan's multiple test were used to analyze the effects of the @entity619 and @entity368 treatments. The results showed that @entity619 decreased body @entity1017 , body weight, and feed efficiency. Protein synthesis was inhibited by in vitro @entity619 exposure. Phosphorylation of @entity3470 and ribosomal protein S6 protein kinase (p70S6K) were inhibited by @entity619 , suggesting the @entity3470 pathway may be involved in @entity619 -regulated muscle protein synthesis. Phosphorylation of @entity8582 -activated protein kinase (AMPK) was not altered in vitro but was reduced in vivo by @entity619 . These results imply that the @entity3470 and AMPK pathways are both involved in retarding muscle development and protein synthesis by glucocorticoids, but the @entity3470 pathway is a critical point linking glucocorticoid and protein synthesis. @entity368 , at least partially, inhibited the effects of @entity619 on protein synthesis via the @entity3470 pathway.
