Fine structure of the ventral and dorsal lobes of the prostate in the young adult Syrian hamster, Mesocricetus auratus.

The normal ventral and dorsal prostatic lobes of the young adult Syrian hamster were examined at the light and electron microscopic levels. Each lobe is composed of branched tubular secretory units separated from each other by loose interacinar connective tissue and draining into the urethra. The lumen of each acinus is lined by a simple epithelium composed of columnar secretory cells with occasional small basal cells. The epithelial layer, with the thin underlying lamina propria, forms a mucosa that is often highly folded. The whole acinus is bounded by a thick muscular stroma. In each of the ventral lobes, there are three main ducts, each one formed of tubular branched tributary secretory units. The walls of the secretory acini are moderately folded. Microvilli dominate the lumenal surface of the secretory epithelial cells. The Golgi complex is very extensive and shows dilated cisternae and secretory vesicles and vacuoles of various sizes. Membrane-bounded secretory granules populate the Golgi and apical areas and are released into the acinar lumen by exocytosis. The rough endoplasmic reticulum is dispersed throughout the cytoplasm, except in the region of the Golgi apparatus. In each of the dorsal lobes, there are several main tubular ducts that open into the urethra. Both proximal (ductal) and distal portions of the glandular tree are secretory in nature. Microvilli and cytoplasmic bulges and blebs dominate the lumenal surface of the secretory cells. The cells are also characterized by highly dilated cisternae of rough endoplasmic reticulum. The secretory cells show heterogeneity in the degree of dilation and distribution of rough endoplasmic reticulum, and this heterogeneity may reflect location in the glandular tree.(ABSTRACT TRUNCATED AT 250 WORDS)