Seasonal Variations in Anterior Pituitary Cell Types of the Emballonurid Bat, Taphozous

The pituitary gland of the Taphozous kachhensis has been studied with special reference to the cytology of the anterior pituitary during different phases of the reproductive cycle. Anterior pituitary in various physiological states has been investigated in order to localise the secretory sites of the trophic hormones by employing several cytochemical staining techniques. Six cell types have been recognized in the anterior pituitary on the basis of their morphological characteristics and tinctorial properties. LTH cells are identified by their hypertrophy and hyperplasia during gestation and lactation. The gonadotrophs exhibit cyclical changes in structure and number. LH cells show hypertrophy and hyperplasia during late pregnancy. The FSH cells are maximum during estrus and degranulated cells are observed during pregnancy. The physiological significance of these cell types during different phases of the reproductive cycle of this bat is discussed.