BACKGROUND

Prostaglandins are a diverse group of locally acting hormones that mediate a variety of physiologic and pathologic processes. Cyclooxygenase (prostaglandin synthase) is a key enzyme in the synthesis of prostaglan-dins, catalyzing the conversion of arachidonic acid (AA) to the obligate intermediate PGH,. Two isoforms of cy-clooxygenase exist that have markedly different tissue expression patterns and physiologic functions. Cycloox-ygenase 1 (COX-1) is constitutively expressed and is thought to be involved in cellular &dquo;housekeeping&dquo; func-tions such as gastric cytoprotection, vascular homeosta-sis, renal maintenance, and reproductive functions such as parturition and ovarian homeostasis and luteolysis. The other isoform, cyclooxygenase 2 (COX-2), is an induci-ble enzyme involved in inflammation, differentiation, mi