PDC31 (THG113.31; ILGHXDYK) is an allosteric and non-competitive inhibitor of FP Prostaglandin Receptor. PDC31 is the D-amino acid-based oligopeptide, is used for smooth muscle contractile agent. PDC31 decreases the strength and duration of uterine contractions in vivo, which can be used for research of preterm labor and primary dysmenorrhea (PD). PDC31 also enhances Ca2+-dependent large-conductance K+-channel in human myometrial cells.