The EP2 receptor is one of four GPCRs that mediate the actions of PGE2. The diverse effects of PGE2 acting via EP2 receptors point to the need to identify novel agonists and antagonists, both to further elucidate the function of this receptor subtype and for use as therapeutics for various diseases. Cayman's EP2 Receptor (rat) STEP Reporter Assay Kit (Luminescence) consists of a 96-well plate coated with both rat EP2 receptor and Secreted Alkaline Phosphatase (SEAP) reporter constructs (EP2 Receptor STEP Plate). Cells grown on the STEP complex will express EP2 at the cell surface. Binding of agonists to EP2 initiates a signal transduction cascade resulting in expression of SEAP which is secreted into the cell culture media. Aliquots of media are removed at time intervals, beginning at approximately six hours, and SEAP activity is measured following addition of a luminescence-based alkaline phosphatase substrate provided in the kit. The kit is simple to use and can be easily adapted to high throughput screening for therapeutic compounds regulating the activation of EP2. PGE2 is included in the kit for use as a positive control. The kit provides sufficient reagents to measure SEAP activity at three time points using the black plates included.