Description
Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). cGMP acts as a second messenger much like cyclic AMP. Its most likely mechanism of action is activation of intracellular protein kinases in response to the binding of membrane-impermeable peptide hormones to the external cell surface. Guanylate cyclase (GC) catalyzes cGMP synthesis. This enzyme converts GTP to cGMP. In turn, peptide hormones such as the atrial natriuretic factor activate membrane-bound GC, while soluble GC is typically activated by nitric oxide to stimulate cGMP synthesis