Ultrastructure of the secretory epithelial cells of the Cowper's gland in the Indian fruit bat, Rousettus leschenaulti (Desmarest) during the reproductive cycle.

The present paper describes the ultrastructural characteristics of the Cowper' glands of the Indian fruit bat, Rousettus leschenaulti during its sexually inactive-breeding cycle. The functional significance of the secretions of the Cowper's gland in reproduction is discussed. In Rousettus, Cowper's glands are small, pear-shaped, bilaterally symmetrical and are situated on either side of the base of the penis. Each lobule is made up of secretory acini lined by columnar or pyramidal cells. Ultrastructurally, the secretory epithelial cells are characterized by well-developed rough endoplasmic reticulum, extensively developed Golgi complex, and mitochondria. Three different types of secretory granules can be identified on the basis of electron density. These granules represent the different stages of granule maturation. The secretory products are released into the lumen both by apocrine and merocrine modes. The secretory material synthesized by the Cowper' gland may be involved in various male reproductive processes of this species of bat.