Hypophysectomy and hormonal therapy modulate mK1-immunoreactive duct cells in the mice sublingual glands

Abstract

The immunocytochemical localization of a true tissue kallikrein, mK1, in mouse sublingual glands (SLGs) was examined following hypophysectomy and hormonal replacement therapy. In the glands of intact mice (14 weeks of age), mK1 was detected in the striated ducts (SDs). Full-fledged granular cells were scattered in the SDs of male mice (but not in those of female mice), showing a cellular mosaic distribution of mK1 with some being positive and others being negative. mK1 was also detected in transitional-type granular cells, though the secretory granules were too small and scarce to be visible by a light microscopy. Hypophysectomy in male mice resulted in the atrophy and loss of secretory granules in many SD cells. Granulation recovered after the repeated injection of 5a-dihydrotestosterone (DHT), 3,5,3 0 -triiodo-L thyronine (T 3 ), and dexamethasone (Dex), given either alone or in combination to the hypophysectomized mice. The concomitant injection of DHT and T 3 , with or without Dex, resulted in the reappearance of the full-fledged granular cells, only some of which were mK1-positive. Electron microscopy revealed mK1 to be present exclusively in the secretory granules of these mK1-positive cells, and no ultrastructural differences were observed between mK1-positive and mK1-negative full-fledged granular cells. These results show that the differentiation of the granular cell phenotype in the mouse SLG duct system requires the concomitant action of androgen and thyroid hormone and retards mK1 synthesis.

Reversible Conversion among Subtypes of Salivary Gland Duct Cells as Identified by Production of a Variety of Bioactive Polypeptides

“…Administration of hormones (DHT, T 3 , or Dex) restored the phenotype of the GCT-like duct cells, and large secretory granules reappeared. These results suggested that GCT-like duct cells of the mouse SLG are also regulated by hormones, and that androgen and thyroid hormones are necessary for phenotype expression and mK1 synthesis in a mechanism similar to that in the SMG GCT [21].…”

Hormone-induced granular convoluted tubule-like cells in mouse parotid gland

“…A few morphologically similar granular duct cells have also been detected in the SD of the mouse sublingual gland (SLG), usually in males, and rarely in females (4). Such GCTlike cells in the SLG express GCT-specific secretory products (5)(6)(7) and are also up-regulated by pituitary-dependent hormones (7). GCT-like cells were induced in the SD of the SLG in female mice treated with androgen (5).…”