L'acquisizione della competenza allo sviluppo nell'ovocita dei mammiferi domestici : ruolo dei fattori intraovarici : dottorato di ricerca in biotecnologie applicate alle scienze veterinarie e zootecniche : tesi di dottorato di ricerca

Ovarian follicular growth and development is characterized by a marked cell proliferation and differentiation. Although it is well established that these processes are regulated primarily by gonadotropins, in recent years it has become evident that other hormones and local factors are involved in ovarian function. The intercellular communication mediated by gap junctions (GJ) plays an important role in the regulation of this process, in fact, through this channel can pass many molecules such as second messengers, nutrients and anti-oxidants as glutathione (GSH). The GJ are present between the oocyte and the cumulus cells (CC) from the earliest stages of follicle growth. In this study we analyzed the oocyte content of GSH, the morpho-functional status of the GJ. Moreover we evaluated the presence of Prolactin (PRL), an hormone which is known to regulate folliculogenesis in many species, and of endothelial nitric oxide synthase (eNOS) because it s the main NO producer in the ovary. Our work identified two classes of ovaries with different characteristics: one indicated as Highly competent that gives oocytes that develop to blastocysts in a higher percentage respect to the low competent with high level of GSH, and posses GJ open. We haven t observed any difference in the distribution of PRL and eNOS. In conclusion, studying the factors involved in the acquisition of developmental competence may lead to a better understanding of these mechanisms and to an improvement of the assisted reproduction techniques.