Cyclic Secretory Activity of the Cowper’s Gland of the Indian Fruit Bat, Rousettus Leschenaulti (desmarest)

The present study describes the cyclical changes in the secretory activity of the Cowper’s gland in the Indian fruit bat, Rousettus leschenaulti. The secretory activity in the Cowper’s gland during the breedingquiescence cycle is not well marked in Rousettus. During the sexually quiescent period (July), Cowper’s glands are regressed, acini are small and are lined by low columnar cells with darkly stained basally to centrally placed nuclei. The cytoplasm shows eosinophilic granular secretion. During the prebreeding (September) and the active breeding period (October to April), the acini are enlarged and are lined by tall columnar epithelial cells. The secretory granules are carried towards the apical plasma membrane and released into the lumen. In some secretory cells, the apical secretory blebs are seen on the surface of the plasma membrane. They detached from the apical plasma membrane and releases into the lumen. Thus, secretory cells show merocrine and apocrine modes of secretion in this species of bats. The lumen of acinus contains a homogenous secretion during active breeding period. Regressive changes in the Cowper’s gland are evident from May. The acinar cells undergo gradual hypotrophy as the quiescent period approaches in June.