Comparative morphology of the pituitary gland in Australian flying foxes (megachiroptera: GenusPteropus)

Abstract

Background Investigations of reproductive endocrinology of flying foxes (genus Pteropus) have been hampered by inadequate information on the normal morphology of the megachiropteran pituitary. Methods The novel technique of graphical three‐dimensional (3‐D) reconstruction, supported by more traditional anatomical techniques, have now been used to examine the shapes of, the interrelations between, the lobes of the pituitary of the little red flying fox, Pteropus scapulatus. Statistical analysis of data from three species tested whether there were changes in pituitary size with annual cycles in function, particularly with key stages of reproduction. Results In the three species of Australian flying foxes examined, the hypophyseal cleft is closed; the pars intermedia extends over the rostral, ventral, and lateral surfaces of the neural lobe. The pars distalis is broad rostrally and extends over two‐thirds of the lateral and ventral pars intermedia. The hypophyseal recess is broad at the median eminence, then narrows and extends through the infundibulum to, but not into, the neural lobe. In adult animals the pituitary weight was 10.0 ± 0.3 mg (mean ± s.e.) in P. scapulatus, 14.7 ± 0.5 mg in Pteropus poliocephalus (greyheaded flying foxes), and 18.7 ± 1.5 mg in Pteropus alecto (black flying foxes). Pituitary weight was not significantly affected by reproductive stage. Conclusions Thus histologically, the adenohypophysis and neurohypophysis are similar to those of other mammals. Comparative differences in pituitary size reflected differences in species body size rather than cyclical reproduction. © 1996 Wiley‐Liss, Inc.

Ultrastructural Characterization of the Pars Distalis of the Indian Female Sheath-Tailed Bat, Taphozous longimanus (Hardwicke)

“…The influence of pituitary hormones, such as, LH, FSH and prolactin are fundamental to reproductive physiology. These cells of pars distalis not only play a pivotal role in reproductive processes of mammals but also show changing morphology during different phases of reproductive cycle of bats (Herlant, 1962;Peyre & Herlant, 1963;Badwaik, 1988Badwaik, , 1991Richardson, 1979;O'Brien et. al., 1996;O'Brien, 2003).…”

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

“…However, the pituitary gland itself has rarely been studied for correlations with the biological processes it controls, or even for its variability in size. This may be due to the difficulty of studying a small organ that is best visualized by histological study (e.g., Patil, ; Anthony and Gustafson, ; King et al, ; Badwaik, ; Bhiwgade et al, ; O'Brien, ; Anthony, ; Azzali et al, ). The size of the hypophysis was studied by Legait et al (), and Bauchot and Legait (), who measured volume of the hypophysis in 50 species of bats.…”

“…The hypothalamic‐pituitary pathway achieves central control of endocrine support of reproduction in bats (Anthony, ). The hypophysis of some commonly studied bats, such as Myotis, Hipposideros , and Pteropus have been microscopically studied (Anthony and Gustafson, ; O'Brien, ), and Legait et al () provided the only study of bat hypophyseal volumes to date. Previously, emphasis has not been placed on the pituitary gland as a compound structure, which is part glandular, part neural.…”

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

“…The influence of pituitary hormones, such as LH and FSH are fundamental to reproductive physiology. These cells of pars distalis not only play a pivotal role in reproductive process of mammals but also show changing morphology during different phases of reproductive cycle of bats [ 4 5 9 24 26 23 28 ].…”

“…Herlant [ 8 ], Peyre and Herlant [ 25 ], Badwaik [ 4 ] and O’Brien et. al [ 24 ] have reported that these cell have different morphological feature at different reproductive phases. In the present study ultrastructure of FSH and LH are described with reference to Golgi body, Endoplasmic reticulum, secretory vesicles, mitochondria and nucleus.…”