Plays a role in signal transduction by regulating the intracellular concentration of cyclic nucleotides cAMP and cGMP. Dual-specificity phosphodiesterase that catalyzes the hydrolysis of both cAMP and cGMP to 5'-AMP and 5'-GMP, respectively. 3',5'-cyclic GMP + H2O = GMP + H(+) 3',5'-cyclic AMP + H2O = AMP + H(+) Binds 2 divalent metal cations per subunit. Site 1 may preferentially bind zinc ions, while site 2 has a preference for magnesium and/or manganese ions. In adults, it is enriched in Malpighian tubules. Belongs to the cyclic nucleotide phosphodiesterase family.