Abstract
Cat+-ATPase activity in rat pancreatic exocrine cells and endocrine cells during perinatal development was cytochemically examined at the electron microscopic level. The intense enzyme activity on the plasma membrane of endocrine cells was observed from the beginning of differentiation of endocrine cells, as well as in adult rats. However, no activity was seen on the plasma membrane of exocrine cells in prenatal rats. Ca2+-ATPase activity on the basolateral plasma membrane of exocrine cells appeared after birth, whereas pancreatic acini and zymogen granules were fully developed during the late embryonic stage. It seemed that the appearance of Ca2+-ATPase activity on the plasma membrane corresponded to the beginning of exocrine secretory function. These results suggest that Ca2+-ATPase activity on plasma membrane of exocrine cells may be deeply involved in the secretory function and/or its regulation.
