Summary
The effects of various dosages and of various time periods of treatment with progesterone have been studied in the spayed, mature rat. Test objects were the cells of the luminal epithelium and of the endometrial stroma which were examined by qualitative and quantitative electron microscopy. No significant response was observed in epithelial or stromal cells until after 12 hrs of progesterone treatment. The nuclei of both cell types were then more circular than earlier with reduced long diameters. The functional significance of this change in configuration is unclear since only in the stromal cells was it followed by nuclear growth. Further, after 12 hrs of treatment the relative amounts of mitochondria and granular endoplasmic reticulum of stromal cells were reduced while the volume of the stromal cell cytoplasm appeared enlarged. This is taken as evidence that progesterone causes an intracellular oedema probably by decreasing cell membrane permeability. This response is probably not specific for the stroma but also includes the luminal epithelium, although the volume of the epithelial cell cytoplasm could not be determined here.
Nucleolar enlargement did occur in stromal cells and was observed after 12 hrs of treatment but was not significant until after 24 hrs. At this point of time the net amount of granular endoplasmic reticulum in stromal and epithelial cells was increased indicating an increased protein synthesis in both cell types. However, only in the stromal cells was this associated with nucleolar enlargement, which supports the idea that progesterone stimulates protein synthesis through different mechanisms in the two cell types.
Testing various dosages of progesterone showed that 0.5 mg had an effect similar to 5 mg of progesterone. When 0.05 mg progesterone was injected the only effect observed was an increase in the amount of apical vesicles of the luminal epithelium, showing that the epithelium is more sensitive to progesterone than the stroma.
Similar content being viewed by others
References
Brown-Grant, K., John, P. N., Rogers, A. W.: Analysis of the effects of progesterone on the synthesis of RNA and protein in the uterus of the ovariectomized rat and on the development of an iodide concentrating mechanism. J. Endocr. 53, 363–374 (1972)
Hechter, O., Krohn, L., Harris, J.: The effect of estrogen on the permeability of the uterine capillaries. Endocrinology 29, 386–392 (1941)
Hooker, C. W., Forbes, T. R.: A bio-assay for minute amounts of progesterone. Endocrinology 41, 158–169 (1974)
Jensen, E. V., DeSombre, E. R.: Mechanism of action of the female sex hormones. Ann. Rev. Biochem. 41, 203–230 (1972)
Ljungkvist, I.: Attachment Reaction of Rat Uterine Luminal Epithelium. I. Gross and fine structure of the endometrium of the spayed, virgin rat. Acta Soc. Med. upsalien 76, 91–109 (1971a)
Ljungkvist, I.: Attachment Reaction of Rat Uterine Luminal Epithelium. II. The effect of progesterone on the morphology of the uterine glands and the luminal epithelium of the spayed, virgin rat. Acta Soc. Med. upsalien 76, 110–126 (1971b)
Ljungkvist, I.: Attachment reaction of rat uterine luminal epithelium. III. The effect of estradiol, estrone and estriol on the morphology of the luminal epithelium of the spayed, virgin rat. Acta Soc. Med. upsalien 76, 139–157 (1971c)
Ljungkvist, I.: Uterine stromal morphology of the spayed, virgin rat when prepared with progesterone and oestrogen for implantation. Z. Anat. Entwickl.-Gesch. 141, 161–169 (1973)
Parr, M. B., Parr, L. A.: Uterine luminal epithelium: Protrusions mediate endocytosis, not apocrine secretion, in the rat. Biol. Reprod. 11, 220–233 (1974)
Stumpf, W. E., Sar, M.: Cellular and subcellular localization of [3H]-progesterone and its metabolites in rat uterus studied by autoradiography. J. Steroid Biochem. 4, 477–481 (1973)
Tachi, C., Tachi, S., Linder, H. R.: Modification by progesterone of oestradiol-induced cell proliferation, RNA synthesis and oestradiol distribution in the rat uterus. J. Reprod. Fert. 31, 59–76 (1972)
Tachi, C., Tachi, S., Lindner, H. R.: Effect of ovarian hormones upon nucleolar ultrastructure in endometrial stromal cells of the rat. Biol. Reprod. 10, 404–413 (1974)
Weibel, E. R., Kistler, G. S., Scherle, W. F.: Practical stereological methods for morphometric cytology. J. Cell Biol. 30, 23–38 (1966)
Author information
Authors and Affiliations
Additional information
This investigation was supported by the Swedish Medical Research Council (project No. B75-12X-4479).
Rights and permissions
About this article
Cite this article
Ljungkvist, I. Quantitative studies of the effect of progesterone on endometrial morphology of the spayed rat. Anat Embryol 148, 47–58 (1975). https://doi.org/10.1007/BF00315562
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00315562