DETECTION OF INDUCIBLE PROSTAGLANDIN-H SYNTHASE-2 IN CELLS IN THE EXUDATE OF RAT CARRAGEENAN-INDUCED PLEURISY

Pleurisy was induced in rats by intrapleural injection of 0.2 ml of 2% lambda-carrageenin. Prostaglandin H synthase (PGHS)-2 was detected us ing immunoblot analysis in cells of the pleural exudate 5 h after carr ageenin injection, and waned at 19 h. PGHS-1 was also detected, but wa s maintained at similar levels in cells before and after carrageenin i njection. The level of PGHS-2 was markedly suppressed by pretreatment of rats with anti-inflammatory dose of dexamethasone (3 mg/kg, i.p.) 2 h before carrageenin injection. Furthermore, only PGHS-1, but not PGH S-2, was detected in the microsomal fraction of the lung, stomach and kidney of pleurisy-affected and non-affected normal rats. These result s suggest the involvement of PGHS-2 in the prostanoid formation in the inflammatory site.