Photoperiod and Testicular Function in Phodopus Sungorus

ISBN-13: 9783540175834 / Angielski / Miękka / 1987 / 76 str.

Martin Bergmann

Opis

Many mammalian species living at medium or higher latitudes show marked annual cycles in various morphological and functional properties. There is a clear cycle of the reproductive activity ranging from a fertile to an infertile state in both the male and female. Such an annual periodicity can be regarded as an adaptation to seasonal changes of environmental conditions such as cli- mate and nutrition, ensuring that birth and development of the litter are re- stricted to a favorable season. These annual cycles consist of cyclic changes of exocrine and endocrine gonadal function, in the hormone-dependent organs (accessory glands, etc.) and in the hormonal hypothalamic-pituitary-gonadal system (for literature, see Hoffmann 1981). Such a seasonal cycle of reproductive activity was found in species from all vertebrate groups (i.e., birds, see Hoffmann 1981; Breucker 1982; reptiles, amphibians, and teleosts, see Hoffmann 1981). In those primate species of the Macaca family which are seasonal breeders (Zamboni et al. 1974), it was demonstrated by Richter et al. (1978) and Wickings and Nieschlag (1980) that these cycles are also evident under constant laboratory conditions, suggest- ing that these cycles are based upon endogenous rhythms which are modulated and synchronized in the natural habitat by exogenous factors.

Spis treści

1 Introduction.- 2 Material and Methods.- 2.1 Groups of Animals.- 2.2 Preparation.- 2.2.1 Light Microscopy.- 2.2.2 Electron Microscopy.- 2.2.3 Enzyme Histochemistry.- 2.2.4 Morphometry.- 3 Results.- 3.1 Testicular Histology in Long Photoperiods.- 3.2 Process of Involution.- 3.2.1 Testicular Weights.- 3.2.2 Diameter of the Seminiferous Tubules.- 3.2.3 Phases of Involution.- 3.3 Morphological Changes Depending on the Phases of Involution.- 3.3.1 Diameter of the Seminiferous Tubules.- 3.3.2 Lamina Propria.- 3.3.3 Sertoli Cells.- 3.3.3.1 Sertoli Cells in Phase I.- 3.3.3.2 Changes of Sertoli Cells in Phases II–VI.- 3.3.4 Blood-Testis Barrier.- 3.3.4.1 Preface.- 3.3.4.2 BTB in Phase I.- 3.3.4.3 BTB in Phases II–VI.- 3.3.4.4 Development of BTB During Recrudescence in Long Photoperiods.- 3.3.5 Leydig Cells.- 3.3.5.1 Leydig Cells in Phase I.- 3.3.5.2 Changes of Leydig Cells in Phases II–VI.- 4 Discussion.- 4.1 Process of Involution.- 4.2 Sertoli Cells.- 4.2.1 Lipid Vacuoles.- 4.2.2 Acid Phosphatase.- 4.2.3 Further Cytological Changes.- 4.3 Blood-Testis Barrier.- 4.4 Leydig Cells.- 5 Conclusions.- 6 Summary.- Acknowledgements.- References.