Effect of clenbuterol on normal and denervated muscle growth and contractility.
The reported anabolic action of some beta 2 agonists may have clinical applications in certain muscle wasting states. Administration of clenbuterol (2 mg/kg diet for 14 days) to rats resulted in a limited degree of hypertrophy of normal muscles; the effect was more pronounced on fast-twitch muscles than on slow-twitch muscles. The anabolic effect was greatest in denervated muscles, where it was significantly more effective on the slow-twitch type. Clenbuterol significantly improved the contractile properties of denervated slow-twitch muscle, reverting them toward normal, but had little effect on contractile properties of denervated fast-twitch muscle. Such differential effects of clenbuterol must be taken into consideration in the evaluation of any future human intervention study.
Agbenyega
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Department of Physiological Sciences, School of Biological Sciences, Medical School, University of Manchester, United Kingdom.
Wareham
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D000818:Animals; D002976:Clenbuterol / Q000494:pharmacology*; D003714:Denervation; D004983:Ethanolamines / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D024510:Muscle Development; D009132:Muscles / Q000187:drug effects* / Q000503:physiopathology; D051381:Rats; D011919:Rats, Inbred Strains
D004983:Ethanolamines; D002976:Clenbuterol