Role of estrogen and progesterone in the regulation of uterine peristalsis: results from perfused non-pregnant swine uteri

BACKGROUND: Adequate uterine contractility and peristalsis are involved in the transport of semen and gametes and in successful embryo implantation. Estrogen and progesterone fluctuate characteristically during the menstrual cycle. It has been suggested that both hormones influence uterine peristalsis in characteristic ways. METHODS: An extracorporeal perfusion model of the swine uterus was used that keeps the uterus in a functional condition and is suitable for the study of physiological questions. The effects of estrogen and progesterone on oxytocin-induced uterine peristalsis were assessed using an intrauterine double-chip microcatheter. RESULTS: Estrogen perfusion was associated with an increase in intrauterine pressure (IUP) in a dose-dependent manner. There was a significant difference between the IUP increase measured in the isthmus uteri and that in the corpus uteri, resulting in a cervico-fundal pressure gradient. Estrogen perfusion resulted in a significantly higher rate of peristaltic waves starting in the isthmus uteri and directed towards the corpus uteri. Progesterone was able to antagonize the estrogen effect in general. CONCLUSIONS: This study demonstrates that estrogen and progesterone have differential effects in the regulation of uterine peristalsis. The present observation shows that estrogen stimulates uterine peristalsis and is able to generate a cervico-fundal direction of peristalsis, whereas progesterone inhibits directed uterine peristalsis.