BACKGROUND The Hippo signaling pathway, a highly conserved cell signaling system, exists in most multicellular organisms and regulates cell proliferation, differentiation, and apoptosis. It has been reported that the members of Hippo signaling are expressed in mammalian ovaries, but the exact functions of this pathway in primordial follicle development remains unclear. METHODS To analyze the ...

In mammalian ovaries, a fixed population of primordial follicles forms during the perinatal stage and the oocytes contained within are arrested at the dictyate stage of meiotic prophase I. In the current study, we provide evidence that the level of cyclic AMP (cAMP) in oocytes regulates oocyte meiotic prophase I and primordial folliculogenesis in the perinatal mouse ovary. Our results show that...

The importance of the initial follicle pool in fertility in female adult mammals has recently been debated. Utilizing a mathematical model of the dynamics of follicle progression (primordial to primary to secondary), we examined whether the initial follicle pool is sufficient for adult fertility through reproductive senescence in CD1 mice. Follicles in each stage were counted from postnatal day...

Follicle assembly is the process by which groups or "nests" of oocytes break down to form primordial follicles. The size of the primordial follicle pool is the major determinant of the reproductive lifespan of a female. Previously, progesterone (P(4)) has been shown to inhibit follicle assembly, while tumor necrosis factor-alpha (TNFalpha) has been shown to promote the apoptosis that is necessa...

Follicle assembly is the process by which groups or ‘nests’ of oocytes break down to form primordial follicles. The size of the primordial follicle pool is the major determinant of the reproductive lifespan of a female. Previously, progesterone (P4) has been shown to inhibit follicle assembly, while tumor necrosis factor-a (TNFa) has been shown to promote the apoptosis that is necessary for fol...

In mammals, the primordial follicle pool represents the entire reproductive potential of a female. The transforming growth factor-β (TGF-β) family member activin (ACT) contributes to folliculogenesis, although the exact mechanism is not known. The role of FST288, the strongest ACT-neutralizing isoform of follistatin (FST), during cyst breakdown and primordial follicle formation in the fetal mic...

BACKGROUND Cyclins regulate the cell cycle in association with cyclin dependent kinases (CDKs). CDKs are under inhibitory control of cyclin dependent kinase inhibitors (CDKIs). METHOD In this study we tested the expression of CDKIs p15, p16, p21 and p27 by immunohistochemistry to determine the role of CDKIs in the initiation of primordial follicle growth. Ovaries were collected from 60-day-ol...

Well-timed progression of primordial folliculogenesis is essential for mammalian female fertility. Progesterone (P4) inhibits primordial follicle formation under physiological conditions; however, P4 receptor that mediates this effect and its underlying mechanisms are unclear. In this study, we used an in vitro organ culture system to show that progesterone receptor membrane component 1 (PGRMC1...

Notch signaling directs cell fate during embryogenesis by influencing cell proliferation, differentiation, and apoptosis. Notch genes are expressed in the adult mouse ovary, and roles for Notch in regulating folliculogenesis are beginning to emerge from mouse genetic models. We investigated how Notch signaling might influence the formation of primordial follicles. Follicle assembly takes place ...

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...