In vivo administration of β₂-agonist clenbuterol and subsequent increase in skeletal muscle mass in neonatal chicks

抄録

In this study, the effect of β₂-agonist clenbuterol administration was investigated in chicks (Gallus gallus domesticus) at 6 days of age. Chicks were given single subcutaneous administration of clenbuterol dissolved in saline at a concentration of 1 mg/kg body weight. Twenty-four hours after clenbuterol administration, the ratio of skeletal muscle weight to body weight was increased in chicks treated with clenbuterol, while their body and heart weight were not affected. Although expressions of IGF-I and myostatin mRNA were not changed, the expression of atrogin-1/MAFbx mRNA was significantly decreased by clenbuterol administration. This observation suggested that administration of clenbuterol to neonatal chicks might increase the proportion of muscle mass to body mass. And the decreased expression of atrogin-1/MAFbx might be involved in the growth of skeletal muscle of chicks treated with clenbuterol.