THE HISTOCHEMISTRY AND CYTOLOGY OF THE SALIVARY GLAND DUCT CELLS

Abstract

Salivary glands of 5 species of mammals were examined by a no. of histochemical and cytological methods. A high concn. of succinic dehydrogenase and esterase activity was found in the ducts. Periodic acid-Schiff positive material was found in the duct cells in relatively small amts. compared with that of the acini, but that which was present in the duct cells was localized diffusely in the distal portions of the cells. These granules appeared to be excreted into the lumen of the ducts. There appeared to be virtually no lipase activity in the ducts or acini; the alkaline phosphatase activity was localized mainly in the capillaries surrounding the ducts and the acini. Acid phosphatase activity was present in ducts and acini, being greater in the latter. The duct cells in the salivary glands of the 2 species examined for this purpose possessed large nos. of mitochondria and a large fragmented, distally situated Golgi apparatus. It is suggested that the results obtained may be best interpreted by the assumption that the duct cells are responsible for the passage of water into the lumen in order to dilute the salivary solids. They also appear to secrete small quantities of PAS-positive material into the saliva and the possibility that they also secrete esterase cannot be excluded.