Ultrastructure de l'endom�tre humain normal: II. Les glandes

The effects of steroids on the fine structure of the endometrium

This brief review illustrates the lack of ultrastructural studies on human endometrium, particularly on well-dated material from normal, fertile women. The glandular epithelium, with its triad of unusual organelles in the early luteal phase, poses fascinating problems in cell biology and, probably for this reason, has attracted the most work. Many problems in reproductive biology, in uterine pathology and in the study of unexplained infertility are crying out for detailed study of the luminal epithelium, the stroma and the blood vessels. If this review, by highlighting the gaps in our knowledge, stimulates research into these areas, it will have been successful.

Intercellular spaces and cell junctions in endometrial glands: their possible role in menstruation

Intercellular spaces and cell junctions in human endometrial glands were studied by elctron microscopy following different methods of fixation. The size of the spaces, known to alter during the cycle, was found to depend also on the method of fixation. Various intrusive cells and different types of cell debris were seen in these spaces. The three most widely recognized cell junctions (desmosomes, tight junctions and gap junctions), were all most abundant near the cell apices. The possible significance of these findings in elucidating the cellular mechanism of menstruation is discussed.

Action of midcycle contraceptive (R 2323) on the human endometrium

Over 2,148 cycles of midcycle oral administration of R 2323 (50 mg. per day on Days 15,16, and 17), the authors recorded a drug-failure pregnancy rate of 5 per cent and an unusually regular cycle length of 28 +/- 2 days. During this trial, endometrial biopsies obtained in the luteal phase were examined by light and electron microscopy and compared to pretreatment biopsies. Light microscopy indicated a weakly secretory endometrium suggestive of some, albeit low, progesterone impregnation. Ultrastructural examination revealed deleterious changes in the development of the nucleolar channel system and giant mitochondria and a delay in the migration of glycogen granules. This low progesterone impregnation could be explained either by a direct effect of R 2323 on cell ultrastructure or by interference with progesterone availability. It would appear that R 2323 acts as a temporary substitute for progesterone at the receptor level but that it does not induce all the biological manifestations of this hormone, in particular, the endometrial changes required for implantation.

Atrophy and apoptosis in the cyclical human endometrium

Electron microscopy of human cyclical endometrium indicates that there is considerable loss of gland epithelial cells with formation of apoptotic bodies in the late secretory, premenstrual and menstrual phases, but also to a lesser extent in the proliferative phase. Apoptotic bodies containing nuclear fragments may be recognised on light microscopy as basophilic or Feulgen positive granules. These granules accumulate in greatest numbers towards the end of the cycle and may be used as an additional aid in dating curettings.

Human endometrial fluid kinetics as observed by scanning electron microscopy

Segments of human endometrium, obtained during different stages of the menstrual cycle, were fixed in glutaraldehyde, processed by critical point drying, coated with carbon and gold, than observed with a scanning electron microscope under magnifications varying from 20 to 200,000. The endometrium was basically made of two different types of cells: secretory nonciliated cells and ciliated cells. Different types of secretory cells at different stages of secretory cycles were observed. The endometrial secretion is apocrine: the apical cell membrane of the endometrial cell ruptures, releasing secretory material. The rupture of cells within a given segment of the endometrium is asynchronous. Development of aptical microvilli, synthesis, storage, and release of endometrial secretory granules, and ciliogenesis are hormone dependent. The response of the ciliated and secretory cells of the endometrium varies throughout the menstrual cycle. This is particularly noted in cell specialization, the development of apical microcilli, and ciliogenesis.