Phosphodiesterase 4 From Wikipedia the free encyclopedia At least four types of the enzyme phosphodiesterase 4 (PDE4) are known: PDE4A PDE4B PDE4C PDE4D See also[edit] 3',5'-cyclic-AMP phosphodiesterase Phosphodiesterase (PDE) PDE4 inhibitor Index of chemical compounds with the same nameThis set index article lists chemical compounds articles associated with the same name.If an internal link led you here, you may wish to change the link to point directly to the intended article.