Cyclic AMP, or cAMP, is a molecule that plays a crucial role in cellular signaling. It acts as a secondary messenger, helping to transmit signals from hormones and other substances outside the cell to its interior. This process is vital for regulating various physiological functions, including metabolism, cell growth, and gene expression. cAMP is produced from ATP (adenosine triphosphate) by the enzyme adenylate cyclase when stimulated by certain hormones, such as epinephrine. Once formed, cAMP activates protein kinases, which then trigger specific cellular responses. This signaling pathway is essential for many biological processes, making cAMP a key player in cell communication.