Normal oocyte maturation depends on signal transmission between granulosa cells and the oocyte. We have analysed the effects of inhibiting (I) cyclic AMP-dependent protein kinase (protein kinase A, PK-A), (II) Ca2+/phospholipid-dependent protein kinase (protein kinase C, PK-C) and (III) calmodulin (CaM) on pig oocyte maturation in vitro, protein synthesis and phosphorylation. The inhibition of ...

The two main body axes in Drosophila become polarised as a result of a series of symmetry-breaking steps during oogenesis. Two of the sixteen germline cells in each egg chamber develop as pro-oocytes, and the first asymmetry arises when one of these cells is selected to become the oocyte. Anterior-posterior polarity originates when the oocyte then comes to lie posterior to the nurse cells and s...

During Xenopus oogenesis, the message transport organizer (METRO) pathway delivers germinal granules and localized RNAs to the vegetal cortex of the oocyte via the mitochondrial cloud (Balbiani body). According to the traditional model, the mitochondrial cloud is thought to break up at the onset of vitellogenesis and the germinal granules and METRO-localized RNAs are transported within the mito...

The oocyte maturation includes nuclear maturation and cytoplasmic maturation before fertilization. Moreover, the oocyte nucleus, the cytoplasm and other cell organelles occur changes, zona pellucida (ZP) synchronously undergoes biochemical and structural modifications in the final maturation phase of oocyte prior to fertilization (ZP maturation). It is reported that ZP modifications, such as gl...

OBJECTIVE During stimulated IVF cycles, up to 15% of oocytes are recovered as immature. The purpose of this study was to investigate the trend of oocyte maturity in repeated ovarian stimulation for IVF. METHODS One hundred forty-eight patients were selected who underwent two consecutive IVF cycles using same stimulation protocol during 2008 to 2010. Ovarian stimulation was performed with FSH ...

Spindle sizes are different in diverse species and cell types. In frogs, the meiotic spindle size is positively correlated with the egg cell volume. Across species, relatively small mouse oocytes (70-80 μm) have a relatively large spindle while larger pig oocytes (about 120 μm) have a considerably smaller spindle. In this study we investigated whether species-specific oocyte spindle size was de...

Maturation arrest of human oocytes may occur at various stages of the cell cycle. A total failure of human oocytes to complete meiosis is rarely observed during assisted conception cycles. We describe here a case series of infertile couples for whom all oocytes repeatedly failed to mature during IVF/ICSI. Eight couples, all presenting with unexplained infertility, underwent controlled ovarian s...

background: leukemia inhibitory factor (lif) is a 45-56 kda glycoprotein that has an important role in proliferation and embryo implantation. its effect on oocyte maturation and how to exert the function remained to be elucidated. methods: immature mice superovulated with human menopausal gonadotropin and germinal vesicle (gv) oocytes were obtained from ovary 48 hours after. gv oocytes were cul...