Comparative Study of the Proliferative Activity of Serous- and Mucous-type Acinar Cells in Developing Mongolian Gerbil Mixed Salivary Glands

We estimated the proliferative activity of serous and mucous acinar cells in mixed-type salivary glands of sucking Mongolian gerbils, using immunohistochemistry with proliferating cell nuclear antigen (PCNA) and in vivo labeling of S-phase cells with the thymidine analog bromodeoxyuridine (BrdU). In both sublingual and Weber\u27s (postlingual) salivary glands, acinar secretory cells showing immunoreactivity for anti-PCNA and anti-BrdU were restricted to serous-type cells that were also positive for a serous component, lysozyme. Some less-differentiated cells found in the serous demilunes or acini, which were negative for lysozyme, also showed proliferative activity, while mucous-type cells never did. These results suggest that in the histogenesis of the mixed gland endpieces, the serous-type cells include immature, differentiating cells, while the mucous-type cells consist of only mature, well-differentiated cells