MyometriumUterine ContractionLabor, ObstetricLeiomyomaUterusUterine NeoplasmsPregnancyOxytocinPregnancy, AnimalReceptors, OxytocinLabor OnsetOxytocicsEndometriumParturitionTocolytic AgentsProgesteroneEstradiolRNA, MessengerObstetric Labor, PrematureMyomaMenstrual CycleDinoprostExtraembryonic MembranesLeiomyomatosisRelaxinDeciduaUterine DiseasesOvariectomyRioprostilReceptors, ProstaglandinMuscle, SmoothProstaglandins FReceptor, Galanin, Type 1Adrenergic beta-3 Receptor AgonistsPlacentaHameliaReverse Transcriptase Polymerase Chain ReactionSheepImmunohistochemistryReceptor, Galanin, Type 2