With age, there is a decline in both the quantity and quality of the pool of follicles and oocytes. Linear extrapolation of follicular depletion in women with regular menses predicts that, by 50 years of age, each ovary would contain 2500 to 4000 primordial follicles. Because the menopausal ovary is largely devoid of follicles, follicular depletion apparently accelerates in the last decade of r...

In the female fetus oocyte numbers peak by 16 weeks of gestation, reaching up to 7 million. They decrease progressively and at the time of birth a female will have about 2 million eggs. As she approaches menarche the woman will have about 500,000. This primordial follicular disappearance continues throughout reproductive life and accelerates approximately 10 years prior to the menopause, by whi...

The number of follicles were compared in different developmental stages after the cryopreservation of human ovarian tissue by open freezing system followed by xenotransplantation into severe combined immunodeficient (SCID)-mice under stimulation, with and without ovariectomy. Ovarian tissue, cryopreserved for fertility preservation was partly examined by LIVE/DEAD viability staining or was tran...

Primordial follicles from different mammal species can survive and enter the growth phase in vitro but do not develop beyond the primary stage. The hypothesis was that, in sheep, in vitro follicular growth is arrested because of a lack of secretion of GDF9 and/or BMP15. Cortical slices of 0.3–0.5 mm thickness issued from 5to 6-month-old lambs were cultured for 15 days. The pieces were fixed on ...

The development of techniques allowing the growth of primordial follicles to mature follicles in vitro has much potential for both reproductive medicine and developmental research. However, human primordial and preantral follicles fail to grow after isolation from the surrounding ovarian stroma. Granulosa cells, which normally undergo apoptosis after ovulation, contain a subpopulation of ovaria...

Objectives: Evaluating the addition effect of J. insularis extract and FSH on the survival, activation and ROS production after in vitro culture of ovine preantral follicles enclosed in ovarian tissue. Methods: In the first experiment, ovarian fragments were fixed (non-cultured control) or in vitro cultured in α-MEM (cultured control), α-MEM supplemented with FSH 50 ng/mL, or in α-MEM supplemen...

Although multiple follicles are present in mammalian ovaries, most of them remain dormant for years or decades. During reproductive life, some follicles are activated for development. Genetically modified mouse models with oocyte-specific deletion of genes in the PTEN-PI3K-Akt-Foxo3 pathway exhibited premature activation of all dormant follicles. Using an inhibitor of the Phosphatase with TENsi...

Ovarian primordial follicles are critical for female reproduction and comprise a finite pool of gametes arrested in development. A systems biology approach was used to identify regulatory gene networks essential for primordial follicle development. Transcriptional responses to eight different growth factors known to influence primordial follicles were used to construct a bionetwork of regulator...

A review is given about follicular populations and aspects of follicular development in cattle. Ovaries of cattle contain two different pools of follicles, the non-growing pool and the growing pool. Entry of primordial follicles into the growth phase occurs throughout the reproductive life. Once follicles are recruited to grow, they are destined to undergo atresia or ovulation. Growth of obliga...

The ultrastructural analysis of oocytes and ovarian follicles has been used to evaluate the effects of assisted reproductive techniques, such as cryopreservation or in vitro oocyte maturation. It also benefits the understanding of such complex mechanisms that occur during folliculogenesis. From the beginning of primordial follicles growth until oocyte maturation in preovulatory follicles oocyte...