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.

Abstract

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 mg.kg body wt-1.day-1) 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*

Substances

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