Cyclic nucleotide phosphodiesterase with a dual specificity for the second messengers cAMP and cGMP, which are key regulators of many important physiological processes (PubMed:15673286). Required for male fertility and male mating behavior (PubMed:20551439). a nucleoside 3',5'-cyclic phosphate + H2O = a nucleoside 5'-phosphate + H(+) 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. Binds 2 divalent metal cations per subunit. Site 2 has a preference for magnesium ions. Type I PDE are activated by the binding of calmodulin in the presence of Ca(2+) (PubMed:15673286). Inhibited by zaprinast and sildenafil (PubMed:15673286). Expressed in the head (at protein level) (PubMed:15673286). Expressed in Malpighian tubules (PubMed:15673286). Expressed in neurons in the brain and ventral ganglia with male flies having higher levels of expression in the abdominal ganglia compared to female flies (PubMed:20551439). Belongs to the cyclic nucleotide phosphodiesterase family. PDE1 subfamily.