Anabolic effects of clenbuterol on skeletal muscle are mediated by beta 2-adrenoceptor activation

Am J Physiol. 1992 Jul;263(1 Pt 1):E50-6. doi: 10.1152/ajpendo.1992.263.1.E50.


The potent anabolic effects of the beta 2-adrenoceptor agonist clenbuterol on skeletal muscle have been reported to be independent of actions on beta-adrenoceptors. In the present study clenbuterol, presented to rats in the diet (4 mg/kg), caused significant increases in gastrocnemius muscle mass, protein, and RNA content and a decrease in epididymal fat pad mass. These effects were not mimicked by oral administration of the beta 2-adrenoceptor agonist salbutamol even at high dose (52 mg/kg diet), and the effects of clenbuterol were not inhibited by addition of DL-propranolol (200 mg/kg diet). However, the selective beta 2-antagonist ICI-118,551 (200 mg/kg diet) reversed the anabolic effects of clenbuterol, and a high dose of DL-propranolol (1,000 mg/kg diet) also inhibited these actions of clenbuterol. Furthermore, continuous infusion of salbutamol (1.15 body via miniosmotic pumps did cause significant increases in muscle mass, protein, and RNA content. These results indicate that the anabolic effects of clenbuterol are dependent on interaction with the beta 2-adrenoceptor. However, a long duration of action appears to be required to induce the anabolic effects of beta 2-agonists.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Albuterol / pharmacology
  • Animals
  • Body Weight / drug effects
  • Clenbuterol / pharmacology*
  • Dose-Response Relationship, Drug
  • Male
  • Muscles / drug effects
  • Muscles / metabolism*
  • Organ Size / drug effects
  • Propranolol / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Receptors, Adrenergic, beta / physiology*


  • Receptors, Adrenergic, beta
  • Propranolol
  • Albuterol
  • Clenbuterol