The fine structure of the epithelial cells of the mouse prostate. I. Coagulating gland epithelium.

The fine structure of the epithelial cells of the anterior lobe, or coagulating gland, of the mouse prostate has been investigated by electron microscopy. This organ is composed of small tubules, lined by tall, simple cuboidal epithelium surrounded by connective tissue and smooth muscle. The epithelial cells are limited by a distinct plasma membrane, which covers minute projections of the cytoplasm into the lumen. The cell membranes of adjacent cells are separated by a narrow layer of structureless material of low density. The cavities of the endoplasmic reticulum are greatly dilated, and the cytoplasmic matrix is reduced to narrow strands, in which the various organelles are visible. The content of the cavities of the endoplasmic reticulum appears as structureless material of lesser density than the cytoplasmic matrix. Material which may be interpreted as secretion products can be seen in the lumina of the tubules. The possible nature of the material inside the cisternal spaces and the secretory mechanisms in these cells is discussed.