We studied the effect of OP-41483.alpha-CD, a stable prostacyclin analog, on, 15-HPETE induced bovine endothelial cell dysfunction, which was assessed by measuring a number of endothelial cells attached to plastic plates. 15-HPETE decreased the number of attached endothelial cells in a concentration- and time-dependent manner. OP-41483.alpha-CD and PGI2 significantly inhibited 15-HPETE induced dysfunction of the cells at a concentration of more than 10(-9)M. Besides, DDA (10(-6) - 10(-4)M) an adenylate cyclase inhibitor, diminished the inhibitory effect of OP-41483.alpha-CD on 15-HPETE induced cell dysfunction in a concentration-dependent manner. Furthermore, OP-41483.alpha-CD increased cAMP levels in the endothelial cells in the range of 10(-10) to 10(-8)M in a dose-dependent manner. These data suggest that OP-41483.alpha-CD could exert an inhibitory action on 15-HPETE induced endothelial cell dysfunction via partly increasing its effect on the intracellular cAMP level.