title: The muscle-hypertrophic effect of clenbuterol is additive to the hypertrophic effect of myostatin suppression.
abstract: BACKGROUND
  In this study we investigated the combined effect of myostatin (MSTN) suppression and β-agonist (clenbuterol) administration on muscle hypertrophy and the phosphorylation of muscle 4E-BP1 and p70S6k, two downstream effectors of the Akt/mTOR anabolic pathway.
  
  
  METHODS
  Female heterozygous MSTN-prodomain transgenic mice (an MSTN suppression model) and wild-type littermates were given 0 or 20 ppm of clenbuterol (CL) in their drinking water, and muscle samples were collected at 1 and 2 weeks after treatment.
  
  
  RESULTS
  CL increased body and muscle mass in both genotypes. Levels of phosphorylated muscle 4E-BP1 and p70S6k were higher in MSTN-prodomain transgenic mice than in wild-type mice. CL increased the phosphorylation of 4E-BP1 and p70S6k in both genotypes.
  
  
  CONCLUSIONS
  The muscle-hypertrophic effect of CL is additive to the effect of MSTN suppression. The combination of MSTN suppression and treatment with β-agonists may be an effective therapeutic approach to combat muscle-wasting conditions.
authors.affiliation: Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, Hawaii, USA. ykim@hawaii.edu
authors.forename: Kyung Ho
authors.initials: KH
authors.lastname: Kim
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Kim
authors.forename: Jinzeng
authors.initials: J
authors.lastname: Yang
mesh_terms: D045930:Anabolic Agents / Q000008:administration & dosage*; D000818:Animals; D002976:Clenbuterol / Q000008:administration & dosage*; D004357:Drug Synergism; D005260:Female; D006984:Hypertrophy / Q000139:chemically induced; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology*; D055435:Myostatin / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011897:Random Allocation
chemical_list: D045930:Anabolic Agents; D055435:Myostatin; D002976:Clenbuterol