Effect of the beta-agonist cimaterol on growth and composition of neonatal rats selected for large and small body size.

The effect of subcutaneous injection of the beta-agonist cimaterol on growth and body composition of neonatal rats differing in growth potential was examined. Rats that represented substrain populations of Charles River CD rats selected for either large or small body size were used. Cimaterol administration resulted in a greater reduction in body weight gain in the Large strain rats. Body growth rate declined linearly with increasing doses of cimaterol in both strains. Percent carcass fat and protein were unchanged with cimaterol treatment. Administration of cimaterol inhibited skeletal muscle growth but caused cardiac hypertrophy. These results suggest that the effectiveness of beta-agonists is influenced by animal genotype.