primordial follicles start growth

This experiment was designed to investigate the postnatal development of the ovary in the Uttara fowl chicken and was conducted on 54 apparently healthy female birds divided into different age groups, namely Day 1 and Weeks 1, 4, 8, 12, 16, 20, 24, 28 with six birds each. During postnatal development, the left ovary gradually increased in size and complexity. The segmentation of the ovary started by 4 weeks, follicular eruption by 8 weeks, small liquor follicles (1-5 mm) appeared by 16 weeks, pre-hierarchical follicles by 20 weeks and hierarchical follicles by 24 weeks of age...

Management strategies utilized during pre-breeding development of replacement heifers can impact fertility and the ovarian reserve. Angus-Hereford crossbred heifers (n = 233) were utilized over a three-year period to determine the effects of administration of a growth promoting implant at either branding or weaning on growth, reproduction, and ovarian development. Heifer calves were randomly assigned to one of three treatments: 1) non-implanted controls (CON; n = 79), 2) implanted at approximately 2 mo of age (average calf age = 58 d) with Synovex-C (BIMP, n = 82), or 3) implanted at approximately 7mo of age (average calf age = 210 d) with Synovex-C (WIMP; n = 72)...

Follicular organization starts during mid-to-late fetal life with the formation of primordial follicles. The bilateral interplay between the oocyte and adjoining somatic cells during follicular growth and ovulation may be sensitive to heat stress (HS). Mechanisms giving rise to pre-ovulatory temperature gradients across reproductive tissues are mostly regulated by the pre-ovulatory follicle, and because the cooling of the gonads and genital tract depends on a counter-current transfer system of heat, HS may be considered a major factor impairing ovulation, fertilization and early embryo development...

Polycystic ovary syndrome (PCOS) is a unification of endocrine and metabolic disorders and has become immensely prevalent among women of fertile age. The prime organ affected in PCOS is the ovary and its distressed functioning elicits disturbed reproductive outcomes. In the ovary, macroautophagy/autophagy performs a pivotal role in directing the chain of events starting from oocytes origin until its fertilization. Recent discoveries demonstrate a significant role of autophagy in the pathogenesis of PCOS. Defective autophagy in the follicular cells during different stages of follicles is observed in the PCOS ovary...

Anti-Mullerian hormone (AMH) is an important reproductive marker of ovarian reserve produced by granulosa cells (GCs) of pre-antral and early-antral ovarian follicles in several species, including cattle. This hormone plays a vital role during the recruitment of primordial follicles and follicle stimulating hormone (FSH)-dependent follicular growth. However, the regulatory mechanism of AMH expression in follicles is still unclear. In this study, we compared the expression of AMH, AMHR-II, BMP2, BMP6, FSHR, and LHCGR genes during follicular development...

Primordial follicles, consisting of granulosa cell (GC)-enveloped oocytes are maintained in a state of developmental arrest until activated to grow. The mechanism that operates to maintain this arrested state in GCs is currently unknown. Here, we show the TGFβ-activated transcription factor SMAD3 is expressed in primordial GC nuclei alongside the cell cycle proteins, cyclin D2 (CCND2) and P27. Using neonatal C57/Bl6 mouse ovaries densely populated with primordial follicles, CCND2 protein co-localised and was detected in complex with P27 by immunofluorescence and co-immunoprecipitation, respectively...

OBJECTIVES: This study aimed to compare the effects of N-acetylcysteine and benfotiamine in protection of ovarian tissue from ischemia caused by slow neovascularization injury due to intraperitoneal ovarian autotransplant in rats. MATERIALS AND METHODS: Twenty-eight female rats were divided into 4 groups, each containing 7 rats. Group 1 only had the abdomen opened and closed, group 2 was the transplant-only group, group 3 received benfotiamine for 3 weeks starting 1 day before the transplant procedure, and group 4 received N-acetylcysteine for 3 weeks starting 1 day before the transplant procedure...

The predisposition for the initiation of folliculogenesis in mammals including humans is programmed to start at fetal life and continues until reproductive capacity. The follicles grow from a pool of primordial follicles which retain the major functions in the entire reproductive life of a female. Anti-müllerian hormone (AMH), a glycoprotein belonging to the transforming growth factor-beta family, has an inhibitory effect on ovarian follicle development. The key regulatory target genes in primordial follicle development are of paramount importance in reproductive biology of female...

Oogenesis is a lengthy, multi-step process occurring in mammals yielding single or multiple oocytes capable of being fertilized upon interaction with male gametes. The overall process is highly complex in nature, starting in the primordial follicles, and its ultimate completion is preceded by the meiotic cycle. There are two major phases in oogenesis: the growth phase, followed by a maturation phase that requires relatively less time. Both phases require energy for the various metabolic processes of the oocytes...

The aim of this study was to examine the influence of dietary flaxseed on the endocrine and ovarian functions of weanling gilts challenged with E. coli and Coronavirus infections treated with dietary probiotic cheeses and to understand the possible mechanisms of its effects on ovarian function. Probiotics were used as a natural substitution for antibiotics and 10% dietary flaxseed is an effective prebiotic which supports the action of probiotics and has other beneficial effects on the organism. Probiotics with or without flaxseed were fed to weanling gilts starting 10 days before and lasting up until 14 days after weaning...

In mouse ovaries, the first wave of folliculogenesis perinatally starts near the medullary region, which directs the initial round of follicular growth soon after birth. At the same time, cortical primordial follicles start forming in the ovarian surface region, and then some are cyclically recruited for the second and subsequent rounds of follicular growth. Recent studies suggest different dynamics between the first and subsequent waves of follicular growth in postnatal ovaries. However, the phenotypic differences between these phases remain unclear...

The aim of this study was to evaluate the effect of growth hormone (GH) in the maintenance of the ovarian primordial follicle reserve. Ovaries from 16 mo old GH-deficient Ames Dwarf (df/df) and Normal (N/df) mice were used. A subgroup of df/df and N mice received GH or saline injections for six weeks starting at 14 mo of age. In addition, ovaries from 12 mo old mice overexpressing bovine GH (bGH) and controls were used. df/df mice had higher number of primordial and total follicles than N/df mice (p < 0...

BACKGROUND: Extensive research is ongoing to empower cancer survivors to have biological parenthood. For this, sperm are cryopreserved prior to therapy and in younger children testicular biopsies are cryopreserved with a hope to mature the germ cells into sperm later on for assisted reproduction. In addition, lot of hope was bestowed on pluripotent embryonic and induced pluripotent stem cells to differentiate into sperm and oocytes. However, obtaining functional gametes from pluripotent stem cells still remains a distant dream and major bottle-neck appears to be their inefficient differentiation into primordial germ cells (PGCs)...

This study evaluated the messenger RNA (mRNA) expression and immunolocalization of all members of the platelet-derived growth factor (PDGF) family in caprine ovaries by quantitative PCR and immunohistochemistry, respectively. Detectable levels of PDGF-A mRNA were not observed in primordial follicles. Higher levels of PDGF-B mRNA were observed in primary follicles than in primordial follicles (P < 0.05). PDGF-D mRNA levels were higher in secondary follicles than in the other preantral follicle categories (P < 0...

INTRODUCTION: We have recently demonstrated that antiandrogen treatment during fetal life resulted in delayed folliculogenesis. The aim of the present study was to investigate the effect of androgen deficiency induced by flutamide on the expression of TGFβ superfamily members and their receptors which are involved in follicle formation and its transition to the primary stage. MATERIAL AND METHODS: Pregnant gilts were injected with flutamide (for seven days, 50 mg/day/kg b...

In pigs, primordial to primary follicle transition occur in the late pregnancy. The interactions between Kit ligand (KL) and its receptor (c-Kit), as well as insulin-like growth factor 1 (IGF1) and cognate receptor (IGF1R) are crucial for the primordial follicle activation. It is well established that hormonal disruption induces abnormalities in the developing reproductive system. Hence, this study investigated the influence of antiandrogen, flutamide, on genes involved in the primordial to primary follicle transition...

The sequence of papers starts with an interview of David Albertini and his extraordinary contribution to the knowledge of 'the most wondrous of cells--the oocyte' and follows with a road map of the life of an oocyte from its origin as a primordial germ cell (PGC) to completion of maturation, evidencing the hurdles encountered during this troubled journey. The female gamete is followed during its migration as a PGC towards the gonadal ridge (Mamsen et al.) and during its entry into meiosis (Spiller et al.), when, for the first time, we are able to read a whole genome transcriptional portrait of precious human PGCs in a comparative analysis with that of the mouse (Diedrichs et al...

Recruitment of primordial follicles is essential for female fertility. Some of the intraovarian growth factors involved in the initiation of primordial follicle growth have been identified, but the exact mechanisms regulating follicle activation are poorly understood. Strong evidence indicates that vasoactive intestinal peptide (VIP), a neuropeptide found in ovarian nerves, plays a role in the physiology of follicle development and function. The aim of the present study was to determine whether VIP might regulate the activation and growth of neonatal rat primordial follicles in an in vitro culture system...

BACKGROUND: In vitro follicle growth is a promising fertility preservation strategy in which ovarian follicles are cultured to produce mature and fertilization-competent oocytes. However, in primates, there has been limited success with in vitro follicle growth starting from primordial and primary follicles because adequate isolation methods and culture strategies have not been established. Understanding how to use primordial follicles for fertility preservation has significant implications because these follicles are the most abundant in the ovary, are found in all females and are fairly resistant to cryopreservation and chemotherapeutics...

The production of fertilizable ova is the consequence of multiple events that start as soon as ovarian development and culminate at the time of ovulation. Throughout their development, germ cells are associated with companion somatic cells, which ensure germ cell survival, growth and maturation. Data obtained in vitro and in vivo on several animal models of germ cell depletion have led to uncover the many roles of germ cells on both ovarian development and folliculogenesis. During ovarian development, germ cells become progressively enclosed within epithelial structures called "ovigerous cords" constituted by pregranulosa cells, lined by a basement membrane...