Histology and carbohydrate histochemistry of the prostate gland of the Brazilian four-eyed opossum (Philander opossum Linnaeus, 1758).

The histology as well as glycogen and mucosubstances were described in the cranial, middle and caudal segments of the disseminate prostate of the Philander opossum. The prostate tubuli show external, medium and internal zones. The stroma presents few thin colagenous fibers while the reticular fibers form a well developed network around the glands. The elastic fibers are scant and only observed amidst the excretory ducts (internal zones). The cranial segment is formed by the narrowest tubuli of the gland. The external and medium zones are formed by cubic or cuboidal epithelium with acidophilic granules in the cytoplasm. The internal zone is lined by slightly acidophilic columnar cells. Several excretory ducts join to each other, before emptying in the urethral lumen. The middle segment is formed by largest and longest tubuli of the gland. The secretory epithelium of the external zone shows 2 morphologically distinct types of cells. The medium zone is formed by cells showing strong acidophilia at basal part and slightly basophilia in the apical part. The caudal segment is formed by cuboidal acidophilic epithelium and show the largest lumen of the gland. The luminal secretion of the gland is constituted by acidophilic fluid and numerous globules. Neutral mucosubstances were demonstrated in epithelium and lumen secretion of the 3 prostatic segments; epithelial glycogen was not found in the medium zone of the middle segment. Sialomucins were detected in the cranial and middle segments. Sulfomucins were not found in the prostate of the Philander opossum.