Expression and distribution of myoepithelial cells in developing bovine parotid gland

The expression and distribution of myoepithelial cells in relation to parotid acinar cells were studied immunohistochemically in bovine fetuses and neonates. Definitive myoepithelial cells first appeared as slender, brown short lines around the perimeters of developing secretion acini at four months of fetal age (in a 26 cm long fetus). At this time, parotid acinar cells possessed no distinct secretory granules in the supranuclear region. The differentiation of myoepithelial cells subsequently progressed during late gestation and birth. In neonates, the myoepithelial cells surrounded the secretory acini and parts of the intercalated ducts.