Open AccessUltrastructural aspects of the follicular cells of the pars tuberalis in bats related to the seasonal cycle
Author(s) -
Azzali Giacomo,
Arcari Maria Luisa,
Spaggiari Brunella,
Romita Giuseppina
Publication year - 2003
Publication title -
the anatomical record part a: discoveries in molecular, cellular, and evolutionary biology
Language(s) - English
Resource type - Journals
eISSN - 1552-4892
pISSN - 1552-4884
DOI - 10.1002/ar.a.10091
Subject(s) - follicular phase , ultrastructure , pars tuberalis , biology , cytoplasm , fragmentation (computing) , follicular cell , microbiology and biotechnology , chemistry , anatomy , endocrinology , hormone , pituitary gland , ecology
The topography and structure of the follicular cells and the follicular cavity of the hypophyseal pars tuberalis (PT) were studied in adult hibernating bats ( Pipistrellus pipistrellus and Rhinolophus ferrumequinum ) of both sexes, during the annual seasonal cycle and the reproductive cycle. The follicular cells were found to be organized around a central cavity. They showed a polyhedral shape and apical microvilli protruding into central cavities. During hibernation, the follicular cells showed active cytoplasmic organelles, clusters of glycogen particles, and lipid droplets. In the supranuclear cytoplasm, 9+2 type cilia, some dense bodies, microvesicular vacuoles, and thin actin‐like filaments (rather scarce during autumn) were detected. The contents of the follicular cavity showed well‐defined ultrastructural seasonal characteristics, with a colloid‐like aspect during awakening and a strongly granular aspect during autumn oestrus and mating. Positive staining for PAS and paraldehyde fuchsin, and a marked reaction to lectins PHA‐L4, MAM, and RCA 60 suggested the presence of sialo‐glycoproteins in the follicular cavities. Both follicular and endocrine PT‐specific cells appeared to mark the boundary of follicular cavities. This finding suggests that the follicular cavity contents are comprised of both types of cells, rather than by cell fragmentation or degeneration products. Anat Rec Part A 273A:763–771, 2003. © 2003 Wiley‐Liss, Inc.