Distribution and effect on the endometrium of progesterone released from a progestasert device

Progestasert devices releasing 65 micrograms of [14C]progesterone daily were inserted in 10 women 3 months prior to elective hysterectomy. Following surgery, specimens were examined by light and electron microscopy and by autoradiography. In three uteri, removed during the early follicular phase, there was a clear contrast between the appearance of the superficial portion of the endometrium in the zone immediately adjacent to the device, when compared to areas away from the progestasert. This difference became more pronounced in four specimens obtained at mid-cycle and tended to diminish during the luteal phase: the number of glands was still lower than normal, but stromal decidual reaction was apparent throughout the functional layer of endometrium; in addition, in portions away from the device, glands showed the characteristics of a secretory phase. Progesterone and/or its metabolites were abundant in the superficial epithelium and in the portion of the glands adjacent to the surface; and also well distributed in the stroma and in the capillary walls. Historadiography however, clearly showed that progesterone barely penetrated the deeper portion of the endometrium. This picture does not substantially change during the entire cycle.