Development of the olfactory glands in fetal and neonatal mice- An electron microscopic observation – *
To clarify the development of the olfactory glands at the ultrastructural level, the olfactory mucosae of ICR-mice were examined at 17 days of gestation, at birth and at six days after birth by transmission electron microscopy. The formation of secretory granules in the secretory cells could not be identified until birth. At birth, a small number of secretory granules, appeared and then a marked increase in their number occurred between 0 and six days. Secretory cells at birth contained small granules of high electron density, but, at six days, their electron density had become low. Enlarged granules became fused with neighboring granules, and the contents of apically situated granules were extruded from the cells by exocytosis. The acinus lumen became enlarged at six days after birth. The ducts of the olfactory glands in fetuses had numerous microvilli, and the lumen was very narrow, although, it expanded markedly after birth. In addition, duct epithelial cells, cuboidal during the fetal period, became flattened in neonates. Ultrastructurally, the secretion activity of the olfactory glands showed a marked increase, especially during the neonatal period. (Accepted on September 13, 2005)
