Originally published as JHC exPRESS on October 13, 2009. doi:10.1369/jhc.2009.954636 Journal of Histochemistry and Cytochemistry Volume 58 (2): 157-171, 2010 Copyright © 2010 Raucci & Di Fiore
The Maturation of Oocyte Follicular Epithelium of Podarcis s. sicula Is Promoted by D-Aspartic Acid
Department of Life Sciences, Second University of Naples, Caserta, Italy Correspondence to: Franca Raucci, École Normale Supérieure de Lyon, Institute of Functional Genomics of Lyon, Department of Functional Genomics of Reproduction, 46 Allée d'Italie, 69007, Lyon, France. E-mail: franca.raucci{at}ens-lyon.fr We investigated whether the maturation of oocyte follicular epithelium of lizard is affected by D-aspartic acid (D-Asp). Our results demonstrated that D-Asp is endogenously present in the oocytes, and its distribution varies during the reproductive cycle and following intraperitoneal administration. At previtellogenesis, it is observed in the cytoplasm and nucleus of pyriform cells, in intermediate cells, in some small cells of the granulosa, in the ooplasm, and in some thecal elements. At vitellogenesis, D-Asp is localized in the proximity of the zona pellucida, in the theca, and in the ooplasm. Injected D-Asp is mainly captured by pyriform cells and ooplasm of previtellogenic oocytes, but a moderate accumulation is evident in the cytoplasm of some small granulosa cells and in the theca. D-Asp also increases the ovarian and plasmatic levels of 17β-estradiol and decreases those of testosterone. As a direct and/or indirect consequence of D-Asp, previtellogenic oocytes grow up and mature, resulting in a higher accumulation of carbohydrates in the granulosa, zona pellucida, and ooplasm, but also a reduction in the thickness of the granulosa layer and an increase of the theca stratum. Taken together, our results show that D-Asp may be related to the synchrony of reproduction, either enhancing the growth and maturation of follicular epithelium or influencing its endocrine functions. (J Histochem Cytochem 58:157–171, 2010)
Key Words: D-aspartic acid oocyte lizard seasonal breeder reproductive cycle
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