Most striated duct (SD) cells in the adult mouse parotid gland (PAG) have a few small secretory granules. These granules, however, are usually too small and sparse to be detected using light microscopy. Our serial studies have suggested that these PAG SD cells belong to a group of hormone-responsive granular duct cells, similar to the granular convoluted tubule (GCT) cells found in the submandi...
