Lack of effect of circulating prostacyclin on contractility of the non-pregnant human uterus

Summary. To study the effect of prostacyclin (PGI₂) on the contractility of the non-pregnant human uterus, the intrauterine pressures in the isthmus and fundus of the uterus were recorded before, during and after intravenous PGI₂ at different phases of two consecutive menstrual cycles in eight women. Infusions of 1–8 ng of PGI₂ mur^?1 kg^?1 for 20 min caused no changes in intrauterine pressure either during menstruation or any other phase of the cycle when compared with the contractility patterns in the same woman during the control infusion. Thus these data suggest that circulating PGI₂ is not involved in regulating the contractility of the non-pregnant human myometrium.