What is the function of cyclic adenosine monophosphate (cAMP)?

Cyclic adenosine monophosphate (cAMP) serves as a secondary messenger inside of a cell. It is made from ATP by the enzyme adenylate cyclase, which is located on the inner side of the cell membrane. Adenylate cyclase activity is controlled by hormonal signaling. Thus, a hormone is secreted by an endocrine gland and binds to a receptor on a target cell. This binding influences adenylate cyclase activity, which then influences cAMP levels inside the cell. The change in cAMP levels inside the cell affect the activity of specific enzymes. Thus, cAMP is not part of the cell membrane, does not provide energy for the cell, nor is it an endocrine hormone.