Summary
Estradiol benzoate was injected into virgin rats, at a concentration of 50 μg/day, for 7 days. The animals were fixed by perfusion and the mammary glands prepared for electron microscopy. Many myoepithelial cells in the mammary glands were altered as a result of the estradiol treatment. The affected cells had a markedly reduced number of myofilaments that were restricted to a specific region of the cytoplasm. Large foot-like projections with many vesicles extended from the myoepithelial cells into the surrounding connective tissue. The altered cells also had more organelles, suggesting that their metabolic activity was increased. Nuclei in the altered cells had deep infoldings that may reflect an increase in nuclear/cytoplasmic exchanges. The results of this study indicate that estradiol causes specific morphological alterations in myoepithelial cells of the mammary gland.
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The author thanks Ms. T. Anne Doyle for technical assistance and Ms. Pat Phelps for help with the manuscript. This work was supported by Grant Number R01 CA20765, awarded by the National Cancer Institute, DHEW
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Strum, J.M. Estrogen-induced alterations in the myoepithelial cells of the rat mammary gland. Cell Tissue Res. 193, 155–161 (1978). https://doi.org/10.1007/BF00221608
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DOI: https://doi.org/10.1007/BF00221608