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Vol. 65, No. 1, 2002
Issue release date: May 2002
Pharmacology 2002;65:38–48

Distribution and Muscle-Sparing Effects of Clenbuterol in Hindlimb-Suspended Rats

von Deutsch D.A. · Abukhalaf I.K. · Wineski L.E. · Roper R.R. · Aboul-Enein H.Y. · Paulsen D.F. · Potter D.E.
aSpace Medicine and Life Sciences Research Center, bDepartment of Pharmacology and Toxicology, cClinical Research Center, and dDepartment of Anatomy and Neurobiology, Morehouse School of Medicine, Atlanta,Ga.,USA; eBioanalytical and Drug Development Laboratory, Biological and Medical Research Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia

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Based on their anabolic properties in skeletal muscles, β-adrenergic agonists are of interest as potential countermeasures to microgravity-induced skeletal muscle atrophy. The levels of clenbuterol (Cb), a β2-adrenergic agonist, in both plasma and skeletal muscle were higher in hindlimb-suspended rats than in their nonsuspended Cb-treated controls. Cb treatment was shown to help maintain the body weight in suspended rats, while reducing the amount of mesenteric fat. However, hindlimb suspension attenuated Cb’s lipolytic effects. In skeletal muscle, the magnitude of response to unloading and Cb treatment followed a general regional pattern and was muscle and type specific. The highest magnitude of response to unloading was in predominantly slow-twitch muscles, and the least responsive were the predominately fast-twitch muscles.

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