Scanning Electron Microscopy of the Effect of Short-term Hormonal Therapy on Postmenopausal Endometrium

Abstract

A scanning electron microscopic study of the endometrial surface was made in postmenopausal women, both untreated and after short-term hormonal therapy. In the untreated women the endometrial surface was characterized by slightly bulging cell surfaces with few, short microvilli. The surface area of the cells varied. Often a single kinocilium was observed.

After administration of estrogen alone the epithelial cells showed a uniform surface area. The cell surfaces were bulging and possessed numerous fairly long microvilli, which often formed tuft-like structures. The length of the microvilli seemed to depend upon the potency of the estrogen used.

After sequential administration of estrogen followed by a gestagen, the uterine surface was characterized by microvilli and apical protrusions. The microvilli were long and numerous when the priming estrogen was estradiol + estriol, while they were shorter when estradiol valerate was given. The apical protrusions were larger and more numerous after administration of progesterone than after treatment with norgestrel or noretisterone. The type of estrogen used also influenced the development of the protrusions: generally, they were largest and more numerous after treatment with estradiol and estriol followed by progesterone.

It is concluded that by appropriate hormone administration the surface ultrastructure of the menopausal endometrium can be altered to correspond to that of the normal cycle and that the surface morphology obtained is closely correlated to the type of hormone treatment used.