Altered Expression of Epidermal Growth Factor Receptor and Nerve Growth Factor Receptor in the Rat Submandibular Gland treated with Secretagogues / 대한해부학회지

ABSTRACT

The immunohistochemical localization of epidermal growth factor receptor (EGFR) and nerve growth factor receptor (NGFR) in the submandibular gland of rats was investigated after chronic administration of isoproterenol (IPR) or phenylephrine (PEP). The weight of submandibular gland relative to body weight increased sharply by IPR administration for 14 days and reached twice of that in control, while no significant differences were observed after PEP administration. In PTAH staining, the intensity of duct compartments in rats exposed to IPR and PEP were paler than that of controls. But small secretory granules were observed in the GCT cells of IPR administrated groups. Acini showed characteristic features of hypertrophy, decreased in number of nuclei per unit area, after IPR administration, but not after PEP. EGFR immunoreactivities were distributed mainly in the duct compartments including GCT cells, intercalated duct cells and secretory duct cells. EGFR immunoactivities were more intense after both of PEP and IPR administration than those in controls. However, EGFR immunoactivities gradually decreased after IPR administration. NGFR immunoreactivities were distributed mainly in connective tissue cells surrounding ducts, but not in duct cells. Their intensities increased in the rat with PEP administration but decreased by IPR administration. These results demonstrated that EGFR or NGFR is localized mainly in the duct cells or the cells surrounding ducts, respectively, and that both population of EGFR and NGFR immunoreactive cells are altered by PEP and IPR. The results suggest that EGF and NGF may have some physiological roles by binding with their specific receptors in the submandibular gland as well as oral cavity.