Cytomorphological changes in the rabbit oviductal epithelium after human chorionic gonadotropin treatment

An electron microscopic investigation was performed to examine the ultrastructural changes occurring in the rabbit oviductal epithelium after human chorionic gonadotropin (HCG) administration. Mainly, the non-ciliated secretory cells proved to be affected by the hormonal treatment which resulted in qualitative and quantitative modifications of the secretory patterns differently expressed in the ampulla and isthmus. Thus, morphological evidence of intense secretion was observed in both the oviduct regions at preovulatory stages. Following ovulation, timing of expression of active secretory patterns in the ampulla and isthmus correlated well with the rate of gamete transport and relative functional roles of the oviductal regions in the reproductive process. At present, HCG-induced changes concerning the ciliated cells seem to consist of the occurrence of secretory granules responsible for the appearance of "mixed cells".