<p>The present invention provides novel functional assay for G protein coupled receptors (GPCRs), by measuring intracellular cyclic adenosine monophosphate (cAMP) levels utilizing reporter gene driven cell based assay. The novel assay provides both binding affinity as well as mode of action of compounds in a single set. The novel assay of the invention is useful in identification of compounds acting through GPCRs. Furthermore, the assay offers utility in categorizing compounds in to agonist, partial agonist, inverse agonist and antagonist classes. The novel assay can be scaled up to any high throughput format.</p>
