Comparative image analysis of EGF immunoreaction in rat submandibular gland using 3,3'-diaminobenzidine with metal enhancer substrate

The amplification of polymerized diaminobenzidine with physical developers: sensitizing effects of transition metal salts and sulphide

Amplification of metal-complexed polymerized diaminobenzidine by two light-insensitive physical developers was systematically examined in a dot blot model system following either polymerizing diaminobenzidine in the presence of transition metal salts or applying the metal salts post-diaminobenzidine polymerization. The effect of sodium sulphide treatment on subsequent amplification was also investigated. Those metal-diaminobenzidine complexes that facilitated the most powerful amplification were subsequently tested in an immunohistochemical setting. The most dramatic amplification of polymerized diaminobenzidine was observed following its post-polymerization treatment with salts of platinum alone, or gold or vanadium with subsequent sulphide treatment, and allowed previously invisible quantities of polymerized diaminobenzidine to be clearly seen. Three other transition metal salts also improved the amplification of polymerized diaminobenzidine but to a lesser degree, namely nickel alone, and silver or rhodium with subsequent sulphide treatment. Sensitivity was comparable with the colloidal gold-silver amplification system.

Growth hormone and epidermal growth factor in salivary glands of giant and dwarf transgenic mice

Epidermal growth factor (EGF) in rat salivary glands is regulated by testosterone, thyroxin, and growth hormone (GH). Salivary glands of 45-day-old giant and dwarf male and female transgenic mice were examined histologically and by immunohistochemistry (IHC) for EGF. Male giants showed no significant differences from wild-type (WT) parotid and submandibular glands. However, their sublingual glands expressed EGF diffusely and strongly in granular cells within the striated ducts, where they were not found in WT mice. Submandibular gland ducts of female WT were different, having individual granular cells strongly positive for EGF and distributed sporadically along the striated duct walls. Neither female GH-antagonist dwarf mice nor GH-receptor knockout mice had any granular cells expressing EGF in any gland. Obvious presence of granular duct cells in the sublingual glands of giant male mice suggests GH-upregulated granular cell EGF expression. Furthermore, absence of granular duct cells from all glands in female GH-antagonist and GH-receptor knockout transgenic mice suggests that GH is necessary for the differentiation of the granular cell phenotype in female salivary glands.