The long term objective of this project is to develop methods for large scale production and quantification of human prostaglandin H synthase-2 (PGHS-2), a recently discovered enzyme that is differentially regulated and has significantly different properties than the pGHS-1. Data obtained to date in experimental systems suggest that the PGHS-2 isoform plays a significant role in inflammation, reproduction, and possibly carcinogenesis. Methods for large scale production of human PGHS-2 cDNA as the source of human PGHS-2. Availability of large quantities of purified, metabolically active human PGHS-2 will permit accelerated development of non-steroidal anti- inflammatory drugs (NSAIDs) that are selective for PGHS-2, as well as the mRNA molecules that encode these enzymes, would permit the monitoring of the levels of these enzymes in platelets, leukocytes, and other clinical specimens. Specific enzyme immunoassays for these enzymes will accelerate research on the differential expression of PGHS isoforms in different disease states, and to monitor individuals taking low dose aspirin based on its reported antithrombotic and/or anticancer activities.