The effect of estrogen withdrawal upon the tubal epithelium of immature ovariectomized rhesus monkey (Macaca mulatta) pretreated with estradiol dipropionate.

Immature ovariectomized rhesus monkey (Macaca mulatta) were injected intramuscuarly with estradiol dipropionate (EDP) at a dose of 20 micrograms/kg/day for 6 consecutive days and were sacrificed at days 1, 3, 8, 13 and 25 following withdrawal of the hormone. The overall height of the epithelia of the infundibulum (Inf), Ampulla (A) and the isthmus (I) and the status of the ciliated and nonciliated cells therein were observed under both the light and electron microscope and those observed at days 3-25 were assessed against those found at day 1 (control values). The EDP effect on the above aspects did not change significantly at days 3 and 8 as compared to day 1. There was rather an increase of such hormone impact on day 8: this is indicated by the observations that the nonciliated cells possessed a greater number of secretory granules (SG) and/or exhibited signs of higher secretory activity. Possible neosynthesis of SG was discerned on days 3 and 8. Retrogressive changes in the epithelia and in the constituent cell types were evident on day 13; those advanced further on day 25 but to different degrees in different segments. The changes were highest in Inf following by those in A and I in order: Inf greater than A greater than I. All these changes were described and commented upon. It is concluded that the estrogen impact lasts for some time after its withdrawal and that the nature of subsequent regression of any epithelium and of the celltype therein is determined by their position within the tube.