Effects of clomiphene citrate on vaginal epithelium of ovariectomised rats

Scanning electron microscopy and light microscopy have been used to study changes to the vaginal epithelium induced by exogenous hormones and clomiphene citrate (CC) administered to ovariectomised rats. Oestrogen (E2) administration resulted in epithelial cell proliferation and keratinisation. The administration of the E2/anti-E2 CC also resulted in the stimulation of cell proliferation, but not to the extent produced by E2. Lack of keratinisation, a decreased number of epithelial layers and decreased epithelial height were viewed as non-oestrogenic, or retarded oestrogenic, effects of CC. Modifications to the surface of vaginal luminal cells were also apparent following CC treatment. Cell apices were raised and separated by prominent borders; the surface covering consisted of short bulb-tipped microvilli that clumped together to form rosettes. Individual, elongated microvilli were also evident. The results of this study indicate that CC has retarded oestrogenic actions, as well as a unique ability to alter cell and surface morphology to produce characteristics dissimilar to those seen after treatment with E2 and progesterone.