MECHANISM OF ACTION OF TNF-ALPHA-STIMULATED PROSTAGLANDIN PRODUCTION IN CULTURED BOVINE LUTEAL CELLS

Tumor necrosis factor-alpha (TNF-alpha) influences hormone synthesis o f many ovarian cell types and can also exert cytotoxic effects, possib ly by increasing the synthesis of prostaglandins. The purpose of the p resent study was to characterize the mechanism of TNF-alpha-stimulated prostaglandin F-2 alpha (PGF(2 alpha)) production in cultured bovine luteal cells. Inhibitors of RNA and protein synthesis (actinomycin D a nd cycloheximide, respectively) completely blocked TNF-alpha-stimulate d PGF(2 alpha) production. The phospholipase A(2) inhibitor, aristoloc hic acid, prevented TNF-alpha-stimulated, but not basal, PGF(2 alpha) production, whereas the phospholipase C inhibitor, compound 48/80, was without effect. The addition of arachidonic acid to cultures did not overcome the inhibitory effects of cycloheximide or aristolochic acid. In conclusion, TNF-alpha-stimulated prostaglandin production by bovin e luteal cells is dependent upon the stimulation of phospholipase A(2) through mechanisms which require synthesis of RNA and protein.