background: previous studies reported many discrepancies about the effects of corpus luteum (cl) and ovarian follicle size on the developmental competence of oocytes. objective: the aim of this study was to investigate the effects of cl and different size of follicle on the developmental potential of bovine oocytes. materials and methods: after ovarian classification based on presence or absenc...

Cyclic nucleotides cAMP and cGMP are among the main molecules that control maturation of mammal oocytes. The in vitro simulated physiological oocyte (SPOM) method was used to model accumulation oocyte. In current study, we preincubated oocytes cows (not primed with FSH) modulators: N 6,2’-O-dibutyryladenosine 3’,5’-cyclomonophosphate (dbcAMP) 3-isobutyl-1-methylxanthine (IBMX). use SPOM increas...

BACKGROUND Leptin, as a 16 kDa adipokine, is a pleiotropic cytokine-like hormone that primarily secreted from adipose tissue. It also involves in the regulation of energy homeostasis, neuroendocrine function, immunity, lipid and glucose homeostasis, fatty acid oxidation, angiogenesis, puberty and reproduction. The aim of this study was to investigate the effects of in vitro addition of leptin t...

We have compared mouse embryos of three heterozygous, congenic genotypes (with high, medium and low levels of oocyte-coded glucose phosphate isomerase (GPI-1) activity respectively) to test whether 1) the survival time of oocyte-coded GPI-1 activity in the early embryo is affected by its activity level in the oocyte and 2) whether embryo-coded GPI-1 is detected earlier in embryos that inherit l...

In the ovariole of Cynips, cell groups that have arisen in the initial period of oogenesis, presumably from one gonial cell, differentiate into the oocyte and 12 nurse cells (which constitute the nutritive chamber). The oocyte remains connected with the nurse cells by a strand of cytoplasm; the whole group acts as a physiological unit till the completion of vitellogenesis. Ribonucleoproteins ar...

During the last decade oocyte donation has been highly successful for treating women previously thought to be hopelessly infertile. The pregnancy rate after oocyte donation is among the highest reported for any fertility-enhancing procedure. Most investigators have noted an increased rate of obstetric complications in these pregnancies. In particular, pregnancy-induced hypertension appears to o...

BACKGROUND Although cryopreservation of semen is a routine procedure for preserving male gametes, an efficient method of preserving fertility through oocyte freezing has only recently become available for women. In view of the limited female reproductive lifespan, oocyte freezing can now offer women some protection against the decline in fertility with aging. METHODS A survey was performed in...

The quality of the human oocyte determines the success of fertilization and affects the consequent embryo development, pregnancy and birth; it therefore serves as a basis for human reproduction and fertility. The possibility to evaluate oocyte quality in the in vitro fertilization programme is very limited. The only criterion which is commonly used to evaluate oocyte quality is its morphology. ...

Mammalian oocytes grow and undergo meiosis within ovarian follicles. Oocytes are arrested at the first meiotic prophase, held in meiotic arrest by the surrounding follicle cells until a surge of LH from the pituitary stimulates the immature oocyte to resume meiosis. Meiotic arrest depends on a high level of cAMP within the oocyte. This cAMP is generated by the oocyte, through the stimulation of...

With extended periods of time following ovulation, the metaphase II stage oocyte experiences deterioration in quality referred to as post-ovulatory oocyte ageing. Post-ovulatory ageing occurs both in vivo and in vitro and has been associated with reduced fertilization rates, poor embryo quality, post-implantation errors and abnormalities in the offspring. Although the physiological consequences...