Cyclooxygenase-2 expression and function in renal pathophysiology.

Cyclooxygenase (COX) constitutes the rate-limiting enzyme in the biosynthetic cascade of prostaglandin (PG). Evidence has accrued suggesting pathophysiological states with altered COX-2 activity and expression. Recent experimental evidence suggests that COX-2 has a pathogenetic role in some of these derangements. In other situations, the effect of altered COX-2 regulation is unclear or possibly beneficial. These processes suggest new areas for potential use of COX-2-specific inhibitors. Conversely, in some conditions COX-2-specific inhibitors should be avoided. The conventional view is that COX-2 is an inducible enzyme. However, COX-2 is also active in the constitutive production of prostanoids in the kidney. Consequently, the pathophysiological states discussed herein include not only COX-2 induction during inflammation but also derangements in COX-2 expression and function caused by non-inflammatory stimuli.