Effect of postdevelopmental myostatin depletion on myofibrillar protein metabolism.

ABSTRACT: It is unclear whether the muscle hypertrophy induced by loss of myostatin signaling in mature muscles is maintained only by increased protein synthesis or whether reduced proteolysis contributes. To address this issue, we depleted myostatin by activating Cre recombinase for 2 wk in mature mice in which Mstn exon 3 was flanked by loxP sequences. The rate of phenylalanine tracer incorporation into myofibrillar proteins was determined 2, 5, and 24 wk after Cre activation ended. At all of these time points, myostatin-deficient mice had increased gastrocnemius and quadriceps muscle mass (≥27%) and increased myofibrillar synthesis rate per gastrocnemius muscle (≥19%) but normal myofibrillar synthesis rates per myofibrillar mass or RNA mass. Mean fractional myofibrillar degradation rates (estimat

SUBMITTER: Welle S 

PROVIDER: S-EPMC3118593 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature