Effect of the Photoperiod and Administration of Melatonin on the Pars Tuberalis of Viscacha (Lagostomus maximus maximus): An Ultrastructural Study
| Autor: | Edith Perez Romera, Ramón S. Piezzi, Fabian Mohamed, Luis Scardapane, Susana Dominguez, Teresa Fogal |
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| Rok vydání: | 2010 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Histology food.ingredient Photoperiod Rodentia Antioxidants Melatonin Sexual Behavior Animal chemistry.chemical_compound food Microscopy Electron Transmission Species Specificity Internal medicine medicine Animals Ecology Evolution Behavior and Systematics Lagostomus photoperiodism Geography biology Glycogen Reproduction Epithelial Cells Viscacha biology.organism_classification Adaptation Physiological Circadian Rhythm Endocrinology chemistry Pituitary Gland Gonadotropins Pituitary Ultrastructure Seasons Pars tuberalis Anatomy hormones hormone substitutes and hormone antagonists Biotechnology Pituitary pars tuberalis medicine.drug |
| Zdroj: | The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology. 293:871-878 |
| ISSN: | 1932-8486 |
| DOI: | 10.1002/ar.21083 |
| Popis: | The pituitary pars tuberalis (PT) is a glandular zone exhibiting well-defined structural characteristics. Morphologically, it is formed by specific secretory cells, folliculostellate cells, and migratory cells coming from the pars distalis. The purpose of this work was to investigate differences in specific cellular characteristics in the PT of viscachas captured in summer (long photoperiod) and winter (short photoperiod), as well as the effects of chronic melatonin administration in viscachas captured in summer and kept under long photoperiod. In summer, the PT-specific cells exhibited cell-like characteristics with an important secretory activity and a moderate amount of glycogen. In winter, the PT-specific granulated cells showed ultrastructural variations with signs of a reduced synthesis activity. Also, PT showed a high amount of glycogen and a great number of cells in degeneration. After melatonin administration, the ultrastructural characteristics were similar to those observed in winter, but the amount of glycogen was higher. These results suggest possible functional implications as a result of morphological differences between long and short photoperiods, and are in agreement with the variations of the pituitary-gonadal axis, probably in response to the natural photoperiod changes through the pineal melatonin. The ultrastructural differences observed in PT, after melatonin administration, were similar to those observed in the short photoperiod, thus supporting the hypothesis that these cytological changes are induced by melatonin. |
| Databáze: | OpenAIRE |
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