REGULATION OF EICOSANOID SYNTHESIS IN FIBROBLASTS FROM INFLAMED GALLBLADDERS

Gallbladder cell cultures obtained from rabbits subjected to sham or 7 2 h of bile duct ligation (72 h BDL, cholecystitis model) were incubat ed with calcium ionphore (A23187), dibutyryl cAMP (cAMP): and phorbol 12,13-diacetate (phorbol) to determine the intracellular signal transd uction mechanisms responsible for increased inflamed gallbladder eicos anoid synthesis. Incubation of sham and 72 h BDL cell cultures with A2 3187 or phorbol significantly increased, whereas cAMP decreased, relea se of 6-keto-PGF(1 alpha), PGE(2), thromboxane B-2 (measured by enzyme immunoassay) in a dose-related manner. Seventy-two-hour BDL cell cult ures contained a specific 2-fold increased level of prostacyclin synth ase compared to sham cell cultures which was not altered by preincubat ion with A23187, phorbol or cAMP. These findings suggest that increase d PGI(2) release in the sham and inflamed cell cultures following A231 87 and phorbol stimulation was mediated in part via the inositol triph osphate pathway and protein kinase C activation and was not associated with altered cyclooxygenase or prostacyclin synthase content.