Contractile patterns of isolated oviductal smooth muscle under different hormonal conditions

The isthmic portion of the human fallopian tube was excised during surgery and the ampullary-isthmic junction was identified. Muscle strips (1-mm wide) were dissected from the outer longitudinal and the inner circular layers at this region and used for isometric recordings of spontaneous contractile activity in organ bath experiments. It was found that the amplitude and the duration of individual contractions were similar during various phases of normal menstrual cycles, whereas the frequency of contractions was significantly increased during the periovulatory period in both circular and longitudinal muscle. During early pregnancy or treatment with combined oral contraceptives the motility pattern was similar to that observed in the late luteal phase, being characterized by a comparatively low contraction frequency. In the perimenopausal period, irregular patterns were frequently observed whereas preparations obtained from postmenopausal women exhibited a very weak activity with low amplitude and frequency of contractions. Similar activity was encountered in specimens from patients treated with androgens. It is concluded that endogenous estrogens stimulate human oviductal contractility while endogenous progesterone has a depressive action on tubal activity. Both effects occur with a certain delay and are prolonged for up to 3 days, i.e., the changes in the serum levels of ovarian steroids and the induced alterations of tubal contractility are out of phase.