First evidence of holocrine secretory mechanism in granular ducts in mouse mandibular gland

Abstract

The mouse mandibular gland contains granular ducts, which possess a particular structure. They are termed granular ductsbecause they contain numerous granules in the cells lining them, having a secretory activity. We aimed to assess the secretory mechanismin granular ducts. Consequently, we harvested the mandibular glands from five male mice and processed them for histologicalinvestigations. A large number of cells appeared intact, without obvious distortions or disruptions in the cell membrane. Based on themorphological aspect, these cells either transferred the secretory product through exocytosis or were in “standby” mode. There werecells that presented prominent bulges of the apical pole, thus suggesting an apocrine mechanism. Some cells presented discontinuities inthe apical pole and a tendency of granule transfer towards the lumen. According to the morphological aspects, these cells eliminated thesecretory product through a holocrine mechanism. The morphological aspects noticed in this study revealed that the release of secretoryproducts in some cells lining the granular ducts in the mouse mandibular gland can also be achieved through a holocrine mechanism.