Claim: PDE1 has three subtypes and nine localizations.
Evidence: PDE1 has three subtypes, PDE1A, PDE1B and PDE1C which divide further into various isoforms. PDE1A () Smooth muscle, heart, lung, brain, sperm PDE1A1 Heart, lung PDE1A2 Brain PDE1B1 () Neurons, lymphocytes, smooth muscle brain, heart, skeletal muscle PDE1B2 Macrophages, lymphocytes PDE1C () Brain, proliferating human smooth muscle, spermatids PDE1C1 Brain, heart, testis PDE1C2 Olfactory epithelium PDE1C4/5 mRNA is present in the testis