Denervation Increases Clenbuterol Sensitivity in Muscle from Young Rats

Clenbuterol has been shown to ameliorate denervation-induced atrophy and, therefore, clearly has therapeutic potential in the treatment of muscle wasting conditions in man. Previous studies have used dosages in rats which would be unacceptable in clinical practice, but the present results show that denervated muscle has a greater sensitivity to the drug than innervated or cardiac muscle. Fiber hypertrophy and an increase in protein and RNA content could be observed in denervated muscles but not in innervated muscles at a dose of 10-mu-g/kg body weight. When considered on a metabolic body weight basis, the effective dose in rats and the "safe" dose in man are surprisingly comparable. The observations imply that there is good reason to suppose that clenbuterol could be effective in ameliorating similar wasting conditions in man.