Guanylate cyclases constitute a gene family of enzymes that synthesize the second messenger guanosine 3',5'-cyclic monophosphate (cGMP) and play important roles in diverse physiological functions. Here we report a novel, simple and highly sensitive method for measurement intracellular cGMP concentrations using a cAMP-responsive element (CRE) and cGMP-dependent protein kinase (cGK). Transient transfection of the CRE reporter plasmid, encoding a luciferase reporter gene under the control of a modified promoter containing a CRE, and a cGK expression vector into HEK293 cells followed by treatment with 8-bromo-cGMP showed a dose dependent increase in luciferase activity. Moreover, HEK293 cells expressing GC-A or GC-B natriuretic peptide receptors and harboring this reporter system responded to specific ligands in a dose dependent manner. Our results indicate that this reporter gene method enables high throughput screening of receptor-type GC selective agonists in the treatment of cardiovascular diseases and homeostatic dysfunctions. (C) 2011 Elsevier Inc. All rights reserved.