Expression of transforming growth factor β1 in the submandibular gland of the rat

Abstract

We employed immunocytochemical and in situ hybridization techniques to study the expression of transforming growth factor β1 (TGF-β1) in rat submandibular gland. Immunoreactivity for TGF-β1 was observed in the cells of granular convoluted tubules (GCTs), striated ducts, and excretory ducts, whereas it was absent in the intercalated ducts and secretory acini in both male and female rats. Immunoelectron microscopy revealed the ultrastructural localization of TGF-β1 in the secretory granules of GCT cells. On the other hand, signals for rat TGF-β1 mRNA were abundant in the GCT and striated duct cells but were lacking in the excretory duct cells. These results provided evidence for the production of TGF-β1 in the GCTs and striated ducts of rat submandibular gland.