BACKGROUND It has been reported that the progesterone receptor (PR) level is transiently increased within the follicle by LH stimulation and controls cumulus cells in follicles and oocyte maturation. The purpose of this study was to predict developmental competence of human oocytes during IVF via analysis of PR in cumulus cells surrounding mature oocytes. METHODS Prior to oocyte retrieval, th...

The gametes are responsible for passing all the genetic information from one generation to another, giving rise to all the tissues in a developing animal, and ultimately guaranteeing the survival of species. The formation of germ-line stem cells occurs during early development in all animals. The differentiation of these pluripotent cells into mature gametes provides a continuous supply of sper...

Translational regulation of localized mRNAs is essential for patterning and axes determination in many organisms. In the Drosophila ovary, the germline-specific Orb protein mediates the translational activation of a variety of mRNAs localized in the oocyte. One of the Orb target mRNAs is orb itself, and this autoregulatory activity ensures that Orb proteins specifically accumulate in the develo...

Intracellular Ca(2+) oscillations at fertilization are responsible for triggering egg activation. The aim of this study was to examine the effect of the age of the oocyte donor and in-vitro maturation on the generation of Ca(2+) transients at fertilization. The results show that <10% of in-vivo and in-vitro matured oocytes from 19-day old mice develop to the blastocyst stage in vitro. In contra...

BACKGROUND Recent studies suggest a role for luteinizing hormone and human chorionic gonadotrophin receptor (LH/hCGR) signalling in the regulation of the oocyte-cumulus oophorus cell interplay. The present study aimed at assessing the LH/hCGR gene expression in cumulus cells (CCs) surrounding oocytes in patients undergoing controlled ovarian hyperstimulation (COS) before ICSI and to relate the ...

The postnatal mammalian ovary contains the primary follicles, each comprising an immature oocyte surrounded by a layer of somatic granulosa cells. Oocytes reach meiotic and developmental competence via folliculogenesis. During this process, the granulosa cells proliferate massively around the oocyte, form an extensive extracellular matrix (ECM) and differentiate into cumulus cells. As the ECM c...

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 ...

Complete functional oocyte maturation involves many complex processes that occur within preovulatory follicles and are initiated and sustained by the gonadotropins, steroid hormones and many recognized and unrecognized factors. The product of oocyte maturation is a mature egg that has complete nuclear, plasma membrane and cytoplasmic changes that enable normal fertilization and subsequent devel...