Butaprost (TR4979) is a highly selective prostaglandin E receptor (EP2) agonist with EC50 of 33 nM, and Ki of 2.4 uM for murine EP2 receptor. Butaprost is less active against murine EP1, EP3 and EP4 receptors. Butaprost acts as a potent relaxant whereas PGE2 and to a lesser extent PGE1 has significant contractant activities. Butaprost inhibits both FMLP-stimulated [Ca2+]i and aggregation.
