Mitochondria (mt) have been reported to be closely related to the maturation of mammalian oocytes, but their function in oocyte maturation has not been elucidated. In this study, we examined the kinetics of mt and chromatin configuration during in vitro maturation of mouse oocytes to clarify the relationship between oocyte maturation and mitochondrial distribution morphologically. Oocytes were ...

The relationship between the mos protooncogene protein and cAMP-dependent protein kinase (PKA) during the maturation of Xenopus oocytes was investigated. Microinjection of the PKA catalytic subunit (PKAc) into Xenopus oocytes inhibited oocyte maturation induced by the mos product but did not markedly affect the autophosphorylation activity of injected mos protein. By contrast, PKAc did not inhi...

OBJECTIVE This study was aimed to determine the effects of n-hexane on the maturation of mouse oocytes. METHODS Cell culture was used to observe the maturation of mouse oocytes and CLSM was employed to determine their apoptosis. RESULTS Germinal vesicle breakdown (GVBD) and extrusion of the first polar body in mouse oocytes were significantly inhibited by n-hexane. After fertilization, the ...

The present study evaluated the influence of hyperandrogenism on oocyte quality using a murine PCOS model induced by dehydroepiandrosterone (DHEA) and further explored the effect of metformin treatment. Female BALB/c mice were treated with a vehicle control or DHEA (6 mg /100 g body weight) or DHEA plus metformin (50 mg /100 g body weight) for 20 consecutive days. DHEA-induced mice resembled so...

The protein kinase A (PKA)/Cdc25B pathway plays a critical role in maintaining meiotic arrest in mouse oocytes. However, the molecular mechanism underlying this interchange is not known. In this study, we assessed the role of 14-3-3ε interaction with phosphorylated Cdc25B at its Ser321 as the mouse oocyte is released from prophase I arrest. The 14-3-3ε isoform is a highly conserved protein with...

This study examined the event of protein phosphorylation in bovine oocytes during germinal vesicle breakdown (GVBD) and formation of pronuclei following fertilisation in vitro. Immature oocytes were obtained from abattoir materials and cultured in vitro. The oocytes were labelled with [32P]orthophosphate at 3 h intervals from 0 to 12 h following maturation in culture or from 3 to 18 h following...

The resumption of meiosis in Xenopus arrested oocytes is triggered by progesterone, which leads to polyadenylation and translation of Mos mRNA, then activation of MAPK pathway. While Mos protein kinase has been reported to be essential for re-entry into meiosis in Xenopus, arrested oocytes can undergo germinal vesicle breakdown (GVBD) independently of MAPK activation, leading us to question wha...

In the present study, the response of Nili Ravi buffalo oocytes to recombinant human follicle stimulating hormone (rhFSH) (Organon) on meiotic maturation in vitro was examined. Oocytes were matured in vitro in medium containing either 0 or 0.05 IU/ ml rhFSH and the stage of nuclear maturation recorded after 24 hours. The percentage of oocytes in the control group undergoing germinal vesicle bre...

In freshly isolated fully grown pig oocytes at the germinal vesicle (GV) stage, the cytoplasmic microtubules are arranged in a meshwork. This microtubule arrangement is also maintained during the initial phases of meiotic maturation in vitro. A perinuclear array of microtubules is formed immediately before germinal vesicle breakdown (GVBD). Short-term treatment of oocytes with taxol when oocyte...

The growth of vertebrate oocyte stops temporarily at the late diplotene stage of 1 meiotic cell division and stays at that stage until puberty. Before ovulation, the arrest is resumed and enters the 2 meiotic phase and stops again at the metaphase until fertilization. The arrest is mediated by the constant flow of cAMP, which is generated by activated adenylyl cyclase. This state is manifested ...