Phosphatidic Acid-Dependent Activation of Adenosine- 3'-5'-cyclic-monophosphate-phosphodiesterase Is Necessary for Arg-Vasopressin Induction of Myogenesis

Arg8- Vasopressin (AVP) stimulates differentiation of L6 myoblasts (1) likely through activation of phospholipase D (PLD) and generation of phosphatidic acid (PA) (2). Conversely, high intracellular adenosine-3',5'-cyclic monophosphate (cAMP) levels and protein kinase A (PKA) activation inhibit myoblast differentiation (3). Intracellular cAMP level is not only regulated by activation of adenylyl cyclase but also by its hydrolysis due to phosphodiesterase (PDE) activity. We reported that PA can activate specific isoforms of type IV cAMP-phosphodiesterase (PDE4) in vitro (4). Here, we investigate whether AVP-induced differentiation of L6 myoblasts involves activation of PDE4 isoforms by PA.