(1) Background: The binding sites of melatonin, as a multifunctional molecule, have been identified in human, porcine, and bovine samples. However, the binding sites and mechanisms of melatonin have not been reported in sheep; (2) Methods: Cumulus-oocyte complexes (COCs) were cultured in TCM-199 supplemented with melatonin at concentrations of 0, 10-3, 10-5, 10-7, 10-9, and 10-11 M. Melatonin r...

The environment that the cumulus oocyte complex (COC) is exposed to during either in vivo or in vitro maturation (IVM) can have profound effects on the success of fertilisation and subsequent embryo development. Glucose is a pivotal metabolite for the COC and is metabolised by glycolysis, the pentose phosphate pathway (PPP), the hexosamine biosynthesis pathway (HBP) and the polyol pathway. Over...

Background: Cryobiology and in vitro maturation of oocytes are very important tools of reproductive technology. Oocyte plays an important role in fertility. The objective of this research is comparison study the effect of invitro maturation and IVF fertilization of cryopreserved oocyte with fresh oocyte in mice. Materials and Methods: For this purpose, after superovulation was performed oocytes...

Abstract Study question Does long photoperiod exposure cause glycometabolism changes in the cumulus-oocyte complex? Summary answer The levels of key enzymes and substrates involved have changed complex SD rats due to circadian rhythm changes. What is known already Circadian essential for maintaining required reproductive activities mammalians. In our previous research, results reduction ovulati...

BACKGROUND Human spermatozoa appear to be guided by chemotaxis to the oocyte in the female genital tract. While one of the sources of sperm chemoattractants is the cumulus cells that surround the oocyte, the identity of the chemoattractant secreted from them is unknown. Progesterone, recognized to be secreted from cumulus cells, was demonstrated, at the pM concentration range, to be a chemoattr...

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 ability of an oocyte to successfully mature is highly dependent on intrafollicular conditions, including the size and structure of the follicle. Here we present a mathematical model of oxygen transport in the antral follicle. We relate mean oxygen concentration in follicular fluid of bovine follicles to the concentration in the immediate vicinity of the cumulus-oocyte complex (COC). The mod...

In the present study, we evaluated the contributions of antral follicle development and antral granulosa cell-released factor(s) to the acquisition of a mature mouse oocyte plasma membrane organization and cortical granule distribution. This has been performed by comparing in-vitro matured oocytes derived from early antral follicles (here referred to as denuded oocytes) or from pre-ovulatory fo...