Morphologic changes in the granular convoluted tubule cells of the mouse submandibular gland following hypophysectomy and hormonal replacement |
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Authors: | Kurabuchi Shingo |
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Institution: | (1) Department of Histology, The Nippon Dental University School of Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159, Japan Tel. +81-3-3261-8835; Fax +81-3-3263-5152 e-mail: kurabuchi@tokyo.ndu.ac.jp, JP |
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Abstract: | Morphological changes in the granular convoluted tubule (GCT) cells of the male mouse submandibular gland (SMG) were examined
following hypophysectomy and hormonal replacement. Semithin sections stained with Heidenhain's iron hematoxylin showed that
hypophysectomy severely regressed the GCT phenotype. Although only a few dispersed cells containing secretory granules were
observed in the GCT segments under a light microscope, electron microscopy revealed that many regressed cells continued to
constitutively elaborate apical secretory granules (although they were very small) and contained a euchromatic nucleus at
the center of the cell, poor rough endoplasmic reticulum (RER) and Golgi apparatus in the perinuclear region, and well-developed
basal infoldings. These findings suggest that hypophysectomy resulted in atrophy of GCT cells, but that they retained evidence
of being secretory cells. 5α-Dihydrotestosterone (DHT); 3,5,3′-triiodo-l-thyronine (T3); and dexamethasone (Dex) each enhanced the GCT phenotype of hypophysectomized males to some degree. Combined hormonal replacement
with DHT + T3 in hypophysectomized males restored a nearly normal male GCT phenotype with a full complement of secretory granules and rare
basal infoldings, whereas T3 alone induced a normal female-like GCT phenotype, with considerably abundant secretory granules and the usual short basal
infoldings, in hypophysectomized male glands. Furthermore, Dex was found to synergistically enlarge secretory granules when
administered with T3 and/or DHT, although it was only weakly effective in enhancing the GCT phenotype when used alone. Taken together, the above
findings confirmed that the GCT phenotype of the mouse SMG is regulated by the synergistic action of pituitary-dependent hormones.
Received: October 1, 2001 / Accepted: May 13, 2002 |
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Keywords: | Granular convoluted tubule Submandibular gland Hypophysectomy Hormonal regulation Mouse |
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