Phorbol ester inhibits myoblast fusion and activates β-adrenergic receptor coupled adenylate cyclase

Primary cultures of myoblasts, derived from embryonic chick pectoral muscle, were treated with phorbol ester (TPA) for 8–96 h. TPA treatment blocked the fusion of myoblasts along with the expression of the MM form of creatine kinase. Interestingly, TPA treatment markedly increased the activity of β-adrenergic receptor coupled adenylate cyclase (AC) activity. The study suggests that TPA treatment augments the functional interaction between a coupling Ns protein and catalytic unit of AC. The likely significance of these results is briefly presented.