The bulbourethral gland of the rat. Fine structure and histochemistry.

The bulbourethral gland of the rat was studied, using ordinary light microscopy, electron microscopy and histochemistry. It is a lobular gland and, centrally in each lobe, there is a duct, the ampulla, into which the alveoli drain, either directly or via a very short and narrow ductule. In some glands all the alveoli are cyst-like dilated. The alveoli and ampullae are bounded by tall glandular cells with flattened basal nuclei. The cytoplasm is full of secretion granules. There is only one large secretory duct into which all the ampullae open and this leave the gland at one end. In the electron microscope the granules can be seen to be surrounded by a unit membrane, but quite often several granules flow together in a large irregular mess. Some granules have dense corn-like structure, while others are quite light. A non-membrane bounded mass can often be seen in the luminal part of the cells, this projects as a dome in the alveolar lumen. Myoepithelial cells can be seen around the secretory cells. The histochemical investigation showed that the gland cells are in between mucous and seromucous cells. In the main they contain acid mucosubstances, but also some neutral mucosubstances. The acid mucosubstances consist mainly of sulfated acid mucosubstances and a smaller amount of carboxylated acid mucosubstances (sialomucin).