In vitro contractile activity of porcine myometrium during luteolysis and early pregnancy: effect of oxytocin and progesterone.

The mean area under the contractility curve (AUC) was higher in the outer longitudinal muscle layer compared to the inner circular layer in both cyclic and pregnant sows.

• Both myometrial layers exhibited spontaneous contractility during luteolysis and early pregnancy.
• Pregnant sows showed higher AUC in both muscle layers compared to cyclic sows.
• Oxytocin increased the AUC and frequency of contractions in the outer longitudinal layer, with greater effectiveness observed during luteolysis.
• The response of the outer longitudinal layer to oxytocin was related to the initial spontaneous contractility level.
• The presence of an oxytocin antagonist inhibited the contractile response in the outer longitudinal layer.
• In pregnant sows, progesterone inhibited oxytocin-stimulated contractile activity in the myometrium.

AI simplified