Changes of plasminogen activator in human uterine tissue induced by intrauterine contraceptive devices.

Potassium thiocyanate-extractable uterine plasminogen activator activity was determined to be highest in the endometrium surrounding intrauterine devices (IUDs). Such activity was significantly higher than that encountered in control endometrium or in the endometrium remote to IUDs. As in control cases, extracted endometrial activity fluctuated during the intermenstrual ovarian cycle. It was highest in the pre- or periovulation part of the cycle, and it rose again prior to menstruation. These peaks of activity seem to correspond to times in the cycle when metrorrhagia and abnormal menstruation are usually encountered. Possible implications of the myometrial and endometrial patterns of plasminogen activator in control and IUD-exposed uterine tissue are discussed.