PDE isozyme (and subtype) | Substrate Specificity | Tissue Distribution |
PDE1 (A, B) | cAMP < cGMP | Heart, skeletal muscle, brain, liver, vascular smooth muscle |
PDE2 (A) | cAMP = cGMP | Heart, brain, skeletal muscle, adrenal cortex, corpus caverrnosum |
PDE3 (A, B) | cAMP > cGMP | Heart, brain, corpus cavernosum, vascular and visceral muscle, platelets, liver, kidney |
PDE4 (A, B, C, D) | cAMP > cGMP | Brain, testes, skeletal, visceral and vascular muscle, heart, leukocytes |
PDE5 (A) | cGMP > cAMP | Corpus cavernosum, platelets, visceral and vascular muscle, pancreas, brain, liver, lung |