The Cyclic AMP Pathway

Cyclic adenosine 3 ′ ,5 ′ -monophosphate (cAMP) was the first second messenger to be identified and plays fundamental roles in cellular responses to many hormones and neurotransmitters (Sutherland and Rall 1958).The intra-cellular levels of cAMP are regulated by the balance between the activities of two enzymes (see Fig. 1): adenylyl cyclase (AC) and cyclic nucleotide phosphodiesterase (PDE).Different isoforms of these enzymes are encoded by a large