The aim of the present study was to develop a treatment protocol for the precise synchronization of oestrus that would avoid the development of persistent dominant ovarian follicles. Bos indicus heifers, in which oestrous cycles had been presynchronized, were allocated randomly, according to the day of their oestrous cycle, to one of five treatment groups. All heifers received a subcutaneous ea...

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...

Successful ovulation requires that developmentally competent oocytes are released with appropriate timing from the ovarian follicle. Somatic cells of the follicle sense the ovulatory stimulus and guide resumption of meiosis and release of the oocyte, as well as structural remodelling and luteinization of the follicle. Complex intercellular communication co-ordinates critical stages of oocyte ma...

In mammals, ovulation requires a tight control of extracellular matrix modifications, within both the follicle wall and the inner mass of granulosa cells surrounding the oocyte, namely the cumulus cells. During the pre-ovulatory period, mural granulosa cells promote selective degradation of perifollicular matrix, resulting in the formation of a follicle rupture site. Conversely, cumulus cells s...

Gonadotropins are responsible for maturation of the ovarian follicle and the oocyte. Ovulation is the ultimate step in this process and involves disintegration of the follicular wall and subsequent release of an oocyte into the oviduct. These events are triggered by a surge of luteinizing hormone (LH). Genes expressed in the ovary, that respond to LH, are likely to be involved in the biochemica...

It is believed that during the spring transition, the developing follicle tends to grow more slowly, persist longer and grow to a larger diameter prior to ovulation than at subsequent oestrus periods. A general suspicion, that the first ovulation of the year is less fertile than subsequent ovulations could be explained by a slower growth rate of the ovulatory follicle during transition with the...

Aim Several studies have indicated that the cause of the increased birthweight of frozen-thawed embryos was associated with assisted reproductive technology (ART) procedures, such as cryopreservation. In the present study, the mean birthweight of singletons was compared between the ovulatory and hormone replacement therapy (HRT) cycles in order to investigate the primary factor that leads to hi...

background: globozoospermia is a rare (incidence of 0.1% among andrological patients) and poorly understood condition, but a severe disorder in male infertility. this case report detailed the course of treatment and protocol of a patient with type 1 globozoospermia using intracytoplasmic sperm injection (icsi) and oocyte activation by calcium ionophore, which yielded conception and birth of a h...