Immunohistochemical observation of EGF and NGF in submandibular glands after duct ligation with or without testosterone administration.

Immunohistochemical detection of epidermal growth factor (EGF) and nerve growth factor (NGF) was carried out in duct-ligated submandibular glands (SMG) of mice with or without testosterone treatment. High levels of EGF and NGF were limited to granular convoluted tubule (GCT) cells in normal adult male mice, and reduced levels were evident in the female. After duct ligation, EGF and NGF stainings began to decrease on the 2nd or 3rd day, and by the 10th day, no staining was detectable. Decreasing levels of EGF and NGF following duct ligation, were more pronounced in the male SMG than in the female. Testosterone administration before ligation resulted in decreased EGF and NGF levels of staining; however, staining of sections on the 1st and 3rd day was a little stronger than comparable stained sections of untreated mice. In contrast, testosterone administration after duct ligation showed GCT cells of normal size with some degranulation at 10 days and irregular staining of growth factors with varying degrees of degranulation at 14 days. Histochemical staining for EGF and NGF in this group was marked, as in the normal, until the 10th day with decreasing reactions by the 14th day.