Comparative morphology of the pituitary gland in Australian flying foxes (Megachiroptera: genus Pteropus)

Ultrastructural characterization of Gonadotrophs in the Wild caught female bat Taphozous nudiventris kachhensis (Dobson)

Present study has been design to observe the ultramicroscopic structure of Gonadotrophs in the female bat Taphozous nudiventris kachhensis during the various phases of reproductive cycle. During the present study specimen were collected during Estrous and pregnancy to know the probable role of Gonadotrophs (FSH, LH) in respective stage of reproductive cycle. After collecting female specimen they were weight and dissect out for the pituitary gland and then those were fixed in ice cold gluteraldehyde. Gonadotrophs (FSH and LH) are mostly frequently observed cell types after Somatotrophs cells in the pars distalis of the female bat Taphozous nudiventris kachhensis. FSH cell during estrus is large, ovoid to polyhedral in shape with irregular shaped nucleus. Cell cytoplasm shows well developed Golgi apparatus, rough endoplasmic reticulum and mitochondria this indicating active state. During early pregnancy cytoplasm of FSH cell appears vacuolated because of dilation of rough endoplasmic reticulum. Mitochondria are spherical to rod shaped with lamellar cristae. During late pregnancy rough endoplasmic reticulum shows dilation. Golgi complex is juxtanuclear in position and mitochondria are numerous. LH cells during early part of gestation are large with bilobed nucleus. Cell cytoplasm shows well developed rough endoplasmic reticulum heavily dotted with ribosomes and contains large number of secretory granules. Hypertrophied LH cell in pars distalis of bat during late pregnancy shows well developed rough endoplasmic reticulum occupies major part of cytoplasm. Golgi zone is well developed with dilated saccules. Secretory granules are very few.

The Chiropteran Brain Database: Volumetric Survey of the Hypophysis in 165 Species

For nearly two decades, a database of brain structures from a large sample (272 species) of chiropterans has been widely accessible and used for socioecological analyses of mammals. However, this database remains incomplete since the hypophysis has not been measured. Since this glandular/neural structure has reproductive significance to chiropterans as for other mammals, this investigation was carried out using serial coronal sections of bat brains comprising the Heinz Stephan collection, Düsseldorf, Germany. Complete serially sectioned brains were examined in 313 individuals (165 species, 15 families). Using a well-documented method, hypophyseal volumes were determined from every fourth or sixth section in each individual. The strongest correlation was between body weight and the hypophysis (R(2) = 0.887) and its various components as well as between body weight and adenohypophysis (R(2) = 0.830) and neurohypophysis (R(2) = 0.925). Correlations were also strong for brain weight-adenohypophysis (R(2) = 0.817) and brain weight- neurohypophysis (R(2) = 0.911). Results indicated that: (1) in regression analyses, hipposiderids stand apart as having relatively large adenohypophysis; (2) analysis of residuals generated using least-squares regression of hypophyseal components suggests a trend among microchiropterans where females have a relatively larger adenohypophysis than males. However, this difference is only statistically significant in the largest samples: Phyllostomidae and Vespertilionidae. Pteropodids do not appear to follow this trend. Our findings suggest both phylogenetic and sexual differences in the adenohypophysis in particular, and indicate the need for investigation of larger samples by species, especially those best understood in reproductive and social biology.