Possible microapocrine-type secretion developing in prostatic secretory epithelial cells of older rats in the early...

Secretory epithelial cells at 1 and 2 d after castration became higher than those of control as the result of convex protrusion of the apical cytoplasm into the acinar lumen, which was quickly followed by pinching off the small balloon-like cytoplasmic process developing on its surface. At the same time, the secretory vacuoles became more numerous, while the well-developed Golgi region, prominent rough endoplasmic reticulum and its dilated end facing the Golgi region remeined. On 7 and 14 d after castration, secretory epithelial cells became markedly low and they had very few secretory vacuoles, regressed Golgi region and a markedly reduced amount of rough endoplasmic reticulum. At 7 d after castration, marcrophage-like cells appeared among secretory epithelial cells and acinar basal lamina. These findings might suggest that the involutionary process of secretory epithelial cells was started by apical convex protrusion and accompanied by microapocrine secretion of its subsurface cytoplasm followed by phagocytosis of the remaining disintegrated cytoplasm by macrophage-like cells.