Bimatoprost and its free acid are prostaglandin FP receptor agonists

Bimatoprost (17-phenyl-prostaglandin F(2alpha) ethyl amide) has been reported not to exert its actions via prostaglandin receptors. Here, bimatoprost displaced [3H]prostaglandin F(2alpha) from FP receptors (K(i)=6310+/-1650 nM). Bimatoprost rapidly mobilized intracellular CA(2+) ([CA(2+)](i)) via cloned human FP receptors expressed in human embryonic kidney cells (EC(50)=2940+/-1663 nM) and via native FP receptors in 3T3 mouse fibroblasts (EC(50)=2200+/-670 nM). Furthermore, AL-8810 ((5Z, 13E)-(9S,11S,15R)-9,15-dihydroxy-11-fluoro-15-(2-indanyl)-16,17,18,19,20-pentanor-5,13-prostadienoic acid), an FP receptor antagonist, blocked the bimatoprost-induced [CA(2+)](i) mobilization.