Journal articles on the topic 'Early antral follicle'
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Jurgens, Isabella M., Friederike Baumgaertner, Sarah R. Underdahl, Jennifer L. Hurlbert, Kerri A. Bochantin, Kevin K. Sedivec, James D. Kirsch, et al. "PS-6 Nutrition During Early Pregnancy Impacts Offspring Ovarian Characteristics." Journal of Animal Science 100, Supplement_4 (October 22, 2022): 19. http://dx.doi.org/10.1093/jas/skac313.027.
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Abstract During early pregnancy offspring are directly exposed to nutrients consumed by their mother, and the development of their own reproductive tract is underway. The objective of this research was to determine how characteristics of offspring ovaries were affected by different maternal rates of gain during the first trimester of gestation in beef heifers. Before breeding antral follicle counts were determined via ultrasound. Beginning at breeding Angus heifers were managed to achieve one of two rates of gain: low (0.20 kg/d, n = 8; LG) or moderate (0.75 kg/d, n = 8; MG) for the first trimester of pregnancy, after which they were managed as a single group through F1 calving. Calves remained with their dams until weaning and were managed as a single group through breeding. These F1 heifer calves were then synchronized and bred to a single sire using female sexed semen. On the 84th day of gestation (approximate heifer age 17 months) ovaries were removed from the reproductive tract, weighed, and visible antral follicles were counted. Cross-sections from each ovary were post-fixed and embedded in paraffin, then each of 3 sections (5 µm, with 10 sections between to avoid counting follicles more than once) were stained with Hematoxylin and Eosin for histological evaluation. Number of primordial, primary, secondary, and antral follicles were determined for each section. Data were analyzed using the GLM procedure of SAS with significance declared at P ≤ 0.05. The CORR procedure of SAS was used to calculate correlations between pre-breeding antral follicle counts, surface follicle counts, and histological follicle counts. Though no differences were observed in number of visible follicles (P = 0.45), the corpus luteum (CL) was heavier (P = 0.03) and average ovarian length was greater (P = 0.04) in offspring from LG dams compared with those from MG dams. No differences were observed in the number of primordial, primary, secondary, or antral follicles between treatments (P ≤ 0.18). There was a correlation between the number of histological follicles and surface follicles (r = 0.73; P = 0.002) and pre-breeding antral follicles and surface follicles (r = 0.60; P = 0.014), but there was no correlation between pre-breeding antral follicles and histological follicles (P = 0.10). Heavier CLs have a positive correlation with amount of progesterone released, which is essential for pregnancy maintenance. Longer lengths of ovaries suggest more area for follicles to develop, which is indicative of future reproductive success. Data corroborates previous reports regarding positive correlations between antral follicle count determined via ultrasound and counts of surface follicles on extracted ovaries. These findings demonstrate that nutrition during the first trimester of gestation impacts offspring reproductive tract development.
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Orisaka, Makoto, Katsushige Hattori, Shin Fukuda, Tetsuya Mizutani, Kaoru Miyamoto, Takashi Sato, Benjamin K. Tsang, Fumikazu Kotsuji, and Yoshio Yoshida. "Dysregulation of Ovarian Follicular Development in Female Rat: LH Decreases FSH Sensitivity During Preantral-Early Antral Transition." Endocrinology 154, no. 8 (August 1, 2013): 2870–80. http://dx.doi.org/10.1210/en.2012-2173.
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Abstract Several clinical studies have shown a correlation of hypersecretion of LH and polycystic ovary syndrome (PCOS), infertility, and miscarriage in women, suggesting that chronically elevated LH impairs fertility. Growth arrest of small antral follicles in PCOS is also assumed to be associated with an abnormal endocrine environment involving increased LH stimulation, a hyperandrogenic milieu, and subsequent dysregulated FSH action in the ovarian follicles. In this study, we examined whether and how LH modulates follicular development and steroid production during preantral-early antral follicle transition by using a rat preantral follicle culture system. LH augments testosterone and estradiol production in preantral follicles via up-regulating mRNA abundance of CYP17A1 and CYP19A1. LH promotes rat preantral follicle growth, and the follicular size reaches that of early antral follicles in vitro, a response attenuated by the specific androgen receptor antagonist and a targeted disruption of androgen receptor gene. Sustained follicle stimulation by LH, but not by androgen, decreases FSH receptor mRNA levels and FSH receptor signaling and inhibits FSH-induced follicular growth. The data suggest that LH promotes preantral-early antral transition via the increased synthesis and growth-promoting action of androgen. However, chronic LH stimulation impairs FSH-dependent antral follicle growth by suppressing granulosa cell FSHR expression via the modulation of intraovarian regulators, including LH-induced thecal factors.
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Emmen, Judith M. A., John F. Couse, Susan A. Elmore, Mariana M. Yates, Grace E. Kissling, and Kenneth S. Korach. "In Vitro Growth and Ovulation of Follicles from Ovaries of Estrogen Receptor (ER)α and ERβ Null Mice Indicate a Role for ERβ in Follicular Maturation." Endocrinology 146, no. 6 (June 1, 2005): 2817–26. http://dx.doi.org/10.1210/en.2004-1108.
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Abstract Both estrogen receptor (ER) α and β are expressed within the ovary and lack of either of these receptors affects ovarian function. In this study, the role of ERα and ERβ in folliculogenesis and ovulation was further analyzed. Evaluation of ovarian follicle populations in wild-type and ERβ knockout (βERKO) ovaries revealed reduced late antral growth and ovulatory capacity of βERKO follicles, indicated by reduced numbers of large antral follicles and corpora lutea and increased atresia of large antral follicles. An in vitro culture system was used to study growth, rupture, and luteinization of wild-type, ERα knockout (αERKO) and βERKO ovarian follicles. αERKO follicles exhibited wild-type-like growth and ovulation rates but an increased capacity to synthesize estradiol. In contrast, βERKO follicles showed a significant lack of progression from early antral to large antral stage, decreased estradiol production, and reduced ovulation. Expression patterns of several genes involved in follicle maturation and ovulation were analyzed in follicles grown in vitro. Ar, Pgr, and Has2 mRNA expression levels were the same among the three genotypes. However, βERKO follicles showed reduced expression of Cyp19 mRNA during follicle maturation and reduced Lhcgr and Ptgs2 mRNA expression after human chorionic gonadotropin stimulus. Luteinization occurs normally in αERKO and βERKO follicles, shown by increased progesterone secretion and increased cdkn1b mRNA expression after human chorionic gonadotropin. Collectively, these data indicate that ERβ, but not ERα, plays a direct role in folliculogenesis. ERβ appears to facilitate follicle maturation from the early antral to the preovulatory stage.
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Orisaka, Makoto, Jin-Yi Jiang, Sanae Orisaka, Fumikazu Kotsuji, and Benjamin K. Tsang. "Growth Differentiation Factor 9 Promotes Rat Preantral Follicle Growth by Up-Regulating Follicular Androgen Biosynthesis." Endocrinology 150, no. 6 (February 12, 2009): 2740–48. http://dx.doi.org/10.1210/en.2008-1536.
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The transition from preantral to early antral stage is the penultimate stage of ovarian follicular development in terms of gonadotropin dependence and follicle destiny. Although oocyte-somatic cell communication is important in early follicular development, our knowledge of the precise role of the oocyte-derived growth differentiation factor (GDF)-9 during preantral follicle growth is incomplete. We examined whether and by what means oocyte-derived GDF-9 controls follicular development and steroidogenesis during the preantral to early antral transition, by a combination of in vitro gene manipulation (i.e. intraoocyte injection of GDF-9 antisense oligos) and preantral follicle culture. Intraoocyte injection of GDF-9 antisense suppressed rat preantral follicle growth in vitro, whereas GDF-9 enhanced follicular development. GDF-9 augmented testosterone production in preantral follicles. GDF-9 antisense suppressed androgen production and CYP17A1 mRNA expression in cultured follicles, a response attenuated by exogenous GDF-9. The nonaromatizable androgen 5α-dihydrotestosterone rescued the follicular growth arrest caused by GDF-9 down-regulation. The specific androgen receptor antagonist flutamide suppressed GDF-9-induced preantral follicle growth in vitro. The data suggest that GDF-9 plays an important role in promoting preantral follicle growth by up-regulating follicular androgen biosynthesis. GDF-9 is essential for CYP17A1 expression during follicular development from the preantral to the early antral stage.
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Redding, Gabe P., John E. Bronlund, and Alan L. Hart. "Theoretical investigation into the dissolved oxygen levels in follicular fluid of the developing human follicle using mathematical modelling." Reproduction, Fertility and Development 20, no. 3 (2008): 408. http://dx.doi.org/10.1071/rd07190.
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Oxygen levels in the follicle are likely to be critical to follicle development. However, a quantitative description of oxygen levels in the follicle is lacking. Mathematical modelling was used to predict the dissolved oxygen levels in the follicular fluid of the developing human follicle. The model predictions showed that follicular fluid dissolved oxygen levels are highly variable among follicles, due to the unique geometry of individual follicles. More generally, predictions showed that oxygen levels in follicular fluid increase rapidly during the initial early antral stages of follicle growth before peaking in the later early antral phase. Follicular fluid dissolved oxygen levels then decline through to the beginning of the pre-ovulatory phase, from which they increase through to ovulation. Based on the best available parameter estimates, the model predictions suggest that the mean dissolved oxygen levels in human follicular fluid during the late antral and pre-ovulatory phases range between 11 and 51 mmHg (~1.5–6.7 vol%). These predictions suggest that the human ovarian follicle is a low-oxygen environment that is often challenged by hypoxia, and are in agreement with only some published data on follicular fluid oxygen levels. Predictions are discussed in relation to follicle health and oocyte culture.
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Songsasen, N., M. Fujihara, K. Yamamizu, and D. E. Wildt. "184 FOLLICULOGENESIS AND DONOR AGE INFLUENCE MATRIX METALLOPROTEINASE-2 EXPRESSION IN THE DOMESTIC CAT." Reproduction, Fertility and Development 27, no. 1 (2015): 183. http://dx.doi.org/10.1071/rdv27n1ab184.
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Matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) are known to play key roles in the remodelling of extracellular matrix during ovarian folliculogenesis, especially during the final stage of follicle development. To date, little is known about the significance of MMPs and TIMPs during preantral follicle development. This study determined the expression of MMPs and TIMP-1 during various stages of cat folliculogenesis, largely for the purpose of securing information useful to improving in vitro follicle culture. Primordial (~10 follicles/cat), primary (~5 follicles/cat), secondary (~9 follicles/cat), early antral (~9 follicles/cat), and antral (~4 follicles/cat) follicles were physically isolated from ovaries recovered from 15 cats (5 months to 3 years old during follicular stage) undergoing ovariohysterectomy and assessed for expression of MMP-1, -2, -3, -7, -9, and -13 as well as TIMP-1 using real-time quantitative polymerase chain reaction (q-PCR; 2–4 replicates/follicle stage). Additional ovaries were obtained from three prepubertal (6 months old) and three adult (1 year old) cats and ovarian pieces were fixed in Bouin's solution and assessed for MMP-2 and -13 localization using immunohistochemistry. MMP expression data were analysed using the Kruskull-Wallis one-way ANOVA. Follicles from all stages of development expressed MMPs and TIMP-1. Specifically, expression of MMP-2 increased (P < 0.05) as folliculogenesis progressed (10-fold increases from primordial to early-antral and antral stage). There were no differences (P > 0.05) in the expression of other MMPs among follicular classes. For TIMP-1, there was a tendency (P = 0.07) for increased expression after antrum formation (early antral and antral stages). Immunohistochemistry analysis revealed that MMP-2 was expressed in both the oocyte and somatic cells of all follicular stages in prepubertal cats. However, MMP-2 expression was limited to granulosa and theca cells of antral follicles in adult females. MMP-13 was expressed in the granulosa and theca cells of primary, secondary, and antral stage follicles, and there were no differences (P > 0.05) in localization patterns for this protein between prepubertal and adult females. In summary, the study is the first to report the expression of MMPs as well as TIMP-1 in isolated cat follicles. The difference in MMP-2 expression between prepubertal and adult cats suggests that there may be age-specific requirements for in vitro follicle growth. We are keenly interested in this information for underpinning the development of new in vitro microenvironments for growing immature cat follicles. We suspect that such information will be crucial for understanding how to promote the remodelling of the extracellular matrix by creating degradable biomaterials containing MMP-sensitive peptides to allow optimal follicle expansion.
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Fan, Xueying, Ioannis Moustakas, Monika Bialecka, Julieta S. del Valle, Arend W. Overeem, Leoni A. Louwe, Gonneke S. K. Pilgram, Lucette A. J. van der Westerlaken, Hailiang Mei, and Susana M. Chuva de Sousa Lopes. "Single-Cell Transcriptomics Analysis of Human Small Antral Follicles." International Journal of Molecular Sciences 22, no. 21 (November 4, 2021): 11955. http://dx.doi.org/10.3390/ijms222111955.
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Human ovarian folliculogenesis is a highly regulated and complex process. Characterization of follicular cell signatures during this dynamic process is important to understand follicle fate (to grow, become dominant, or undergo atresia). The transcriptional signature of human oocytes and granulosa cells (GCs) in early-growing and ovulatory follicles have been previously described; however, that of oocytes with surrounding GCs in small antral follicles have not been studied yet. Here, we have generated a unique dataset of single-cell transcriptomics (SmartSeq2) consisting of the oocyte with surrounding GCs from several individual (non-dominant) small antral follicles isolated from adult human ovaries. We have identified two main types of (healthy) follicles, with a distinct oocyte and GC signature. Using the CellphoneDB algorithm, we then investigated the bi-directional ligand–receptor interactions regarding the transforming growth factor-β (TGFβ)/bone morphogenetic protein (BMP), wingless-type (MMTV)-integration site (WNT), NOTCH, and receptor tyrosine kinases (RTK) signaling pathways between oocyte and GCs within each antral follicle type. Our work not only revealed the diversity of small antral follicles, but also contributes to fill the gap in mapping the molecular landscape of human folliculogenesis and oogenesis.
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Nagashima, Jennifer B., Andrea M. Hill, and Nucharin Songsasen. "In vitro development of mechanically and enzymatically isolated cat ovarian follicles." Reproduction and Fertility 2, no. 1 (March 23, 2021): 35–46. http://dx.doi.org/10.1530/raf-20-0067.
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Graphical Abstract Isolation of ovarian follicles is a key step in culture systems for large mammalian species to promote the continued growth of follicles beyond the preantral stage in fertility preservation efforts. Still, mechanical isolation methods are user-skill dependent and time-consuming, whereas enzymatic strategies carry increased risk of damaging theca cell layers and the basement membranes. Here, we sought to determine an optimal method to rescue domestic cat (Felis catus) early antral and antral stage follicles from ovarian tissue and to evaluate the influence of isolation strategy on follicle development, survival, and gene expression during 14 days of in vitro culture in alginate hydrogel. Mechanical isolation was compared with 90 min digestion in 0.7 and 1.4 Wünsch units/mL Liberase blendzyme (0.7L and 1.4L, respectively). Mechanical isolation resulted in improved follicle growth and survival, and better antral cavity and theca cell maintenance in vitro, compared with 1.4L (P < 0.05) but displayed higher levels of apoptosis after incubation compared with enzymatically isolated follicles. However, differences in follicle growth and survival were not apparent until 7+ days in vitro. Expressions of CYP19A1, GDF9, LHR, or VEGFA were similar among isolation-strategies. Cultured follicles from all isolation methods displayed reduced STAR expression compared with freshly isolated follicles obtained mechanically or via 0.7L, suggesting that prolonged culture resulted in loss of theca cell presence and/or function. In sum, early antral and antral stage follicle development in vitro is significantly influenced by isolation strategy but not necessarily observable in the absence of extended culture. These results indicate that additional care must be taken in follicle isolation optimizations for genome rescue and fertility preservation efforts. Lay summary The ovary contains hundreds of eggs with only a select few developing from an immature stage through to ovulation over the course of an animal's lifetime. Rescue of eggs from this pool, and the ability to grow them in culture to a mature stage, would be incredibly valuable for fertility preservation efforts in both humans and endangered species. Currently, the isolation of ovarian follicles (eggs with their surrounding helper cells) is a key step in culture systems for large mammalian species, to promote continued growth. Yet, isolation methods may affect the follicle’s future developmental capacity. We evaluated two isolation strategies, mechanical micro-dissection (needle/scalpel blade) and enzymatic digestion (using Liberase blendzyme) on ovaries of domestic cats obtained via routine spay procedures. Mechanically isolated follicles displayed improved growth, survival, and indications of developmental competence in 14-day culture, compared with high concentration (1.4 Wünsch units/mL) enzyme-isolated follicles. However, mechanical isolation was not different from low (0.7 Wünsch units/mL) enzyme for these metrics, or for expression of key genes indicative of follicular cell functions. Further, differences in follicle growth/survival were not apparent until 7+ days in culture. Thus, ovarian follicle isolation strategies influence developmental potential in culture, and extended culture will be required to identify optimal methods for fertility preservation efforts.
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Young, J. M., S. Henderson, C. Souza, H. Ludlow, N. Groome, and A. S. McNeilly. "Activin B is produced early in antral follicular development and suppresses thecal androgen production." REPRODUCTION 143, no. 5 (May 2012): 637–50. http://dx.doi.org/10.1530/rep-11-0327.
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Little is known about the role of activin B during folliculogenesis. This study investigated the expression levels of activin/inhibin subunits (βA, βB, and α), steroid enzyme, and gonadotrophin receptors in theca (TC) and granulosa cells (GC) by QPCR and activin A and B and inhibin A protein levels in follicular fluid (FF) of developing sheep follicles during estrus and anestrus. The effect of activin B on androgen production from primary TC cultures in vitro was also assessed. During folliculogenesis, in anestrus and estrus, FF activin B concentrations and thecal and GC activin βB mRNA levels decreased as follicle diameter increased from 1–3 to >6 mm regardless of estrogenic status. Estrogenic preovulatory follicles had reduced concentrations of FF activins B and A, and TC and GCs expressed higher levels of activin βA mRNA at 3–4 mm, and TCs more inhibin α mRNA at >4 mm stages of development compared with nonestrogenic follicles. Activin B decreased androstenedione production from primary TCs in vitro, an effect blocked by inhibin A. Thus, sheep follicles 1–3 mm in diameter contained high FF levels of activin B, which decreased as the follicle size increased, and, like activin A, suppressed thecal androgen production in vitro, an effect blocked by inhibin. Furthermore, the theca of large estrogenic follicles expressed high levels of inhibin α and activin βA mRNA suggesting local thecal derived inhibin A production. This would inhibit the negative effects of thecal activins B and A ensuring maximum androgen production for enhanced estradiol production by the preovulatory follicle(s).
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Duarte, Ana Beatriz Graça, Roberta Nogueira Chaves, Valdevane Rocha Araújo, Juliana Jales Celestino, Gerlane Modesto Silva, Cláudio Afonso Pinho Lopes, Líliam Mara Trevisan Tavares, Cláudio Cabral Campelo, and José Ricardo de Figueiredo. "Follicular interactions affect the in vitro development of isolated goat preantral follicles." Zygote 19, no. 3 (October 28, 2010): 215–27. http://dx.doi.org/10.1017/s0967199410000237.
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SummaryThe aim of this study was to evaluate the influence of the number of follicles per drop (one or three) and antral follicles on in vitro development of isolated goat preantral follicles. Preantral follicles were isolated through microdissection and distributed individually (control) or in groups of three follicles (treatment) in microdroplets of α-MEM with or without 1000 ng/ml follicle stimulating hormone (FSH) for Experiments 1 and 2, respectively. Experiment 3 was divided into four treatments according to the presence of one or three preantral follicles, associated or not with antral follicles. After culture, oocytes were retrieved from morphologically normal follicles and submitted to in vitro maturation (IVM) and live/dead fluorescent labelling. Results of Experiment 1 (basic medium without FSH) showed that culture of preantral follicles in groups enhances viability, growth and antrum formation after 12 days. However, in the presence of FSH (Experiment 2), only the recovery rate of fully grown oocytes for IVM was significantly affected by grouping of follicles. In Experiment 3, in general, co-culture of preantral follicles with an early antral follicle had a detrimental effect on viability, antrum formation and production of oocytes for IVM. In conclusion, the performance of in vitro culture of goat preantral follicles is affected by the number of follicles per drop, the presence of an antral follicle and FSH.
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McTavish, K. J., K. A. Walters, D. J. Handelsman, and C. M. Allan. "265. Increased FSH activity increases primordial follicle reserve and enhances preovulatory follicle survival in transgenic FSH female mice." Reproduction, Fertility and Development 20, no. 9 (2008): 65. http://dx.doi.org/10.1071/srb08abs265.
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The mammalian female reproductive lifespan is determined by the depletion rate of the finite ovarian follicle reserve established before or shortly after birth. Follicle formation, initiation and early growth are thought to be independent of follicle-stimulating hormone (FSH), whereas antral follicle development requires FSH stimulation. Rising serum FSH is one of the earliest signs of reproductive ageing in women, coinciding with declining fecundity and an accelerated decline in remaining follicle reserves, but whether or not increased FSH plays a direct or feed-forward role in accelerating reproductive ageing remains undetermined. We previously described transgenic (Tg) mice with rising serum human FSH that produced larger litter sizes <20 weeks of age, then rapidly declining litter size from 20–40 weeks old (wo) culminating in premature infertility1. Despite declining fertility, ageing TgFSH females maintained ovulation rates ~3-fold higher than wt females. Follicle quantitation revealed that ovarian antral follicle numbers at diestrus were equivalent in 26 wo TgFSH and wt females. The elevated ovulation rates in TgFSH females may reflect increased preovulatory follicle survival during proestrus, as ~70% of large antral follicles go on to ovulate in TgFSH females, compared with only 30% in wt females. In contrast to the view that higher FSH may increase follicle development and consequently accelerate follicle depletion, examination of follicle reserve revealed that subfertile or infertile 26–52 wo TgFSH females exhibited increased total ovarian primordial follicle numbers (60%, P < 0.05) with no significant change in primary follicle numbers compared with age-matched wt females. Therefore, increased FSH activity appeared to act as a survival factor for primordial follicles. Our current analysis of increased FSH actions in female mice suggests that FSH may enhance the survival of both early (primordial) and late (preovulatory) follicle populations. (1) McTavish KJ et al. Endocrinology. 2007 Sep;148(9):4432–9.
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Snider, Alexandria, Matthew S. Crouse, Shelby Rosasco, Kaitlin M. Epperson, Emmalee J. Northrop-Albrecht, Jerica J. Rich, Chad Chase, Jeremy R. Miles, Adam Summers, and Robert A. Cushman. "240 Beef Heifers with Increased Number of Follicles Have Greater Uterine Luminal Glucose Concentrations." Journal of Animal Science 99, Supplement_3 (October 8, 2021): 128. http://dx.doi.org/10.1093/jas/skab235.233.
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Abstract Increased numbers of antral follicles are associated with greater fertility and a uterine environment that is more supportive of early embryonic development in beef heifers. Glucose is a primary energy source for embryos and glucose concentrations are elevated in uterine luminal fluid (ULF) of pregnant heifers. We hypothesized that ULF glucose concentrations and endometrial transcript abundance for glucose transporters at d16 after insemination would be greater in heifers with increased numbers of antral follicles. Heifers classified with either increased (32 ± 1.1) or diminished (14.7 ± 1.1) antral follicle counts were selected and artificially inseminated following the Select Synch protocol (d0). At d16 after insemination, heifers were sent to the abattoir and reproductive tracts were collected to retrieve conceptuses to determine pregnancy. Uterine luminal fluid was collected, the endometrium was biopsied, total RNA was extracted and glucose transporter transcript abundance was determined. Data were analyzed using the MIXED procedure of SAS with antral follicle group, pregnancy status, and the interaction as fixed effects. Glucose concentrations in ULF were greater (P < 0.05) in heifers with increased antral follicle numbers compared to heifers with diminished numbers (122.65 ± 11.91 vs 84.12 ± 12.42 mg/dL). Glucose ULF concentrations were increased (P < 0.05) in pregnant vs. non-pregnant heifers (124.84 ± 12.81 vs 81.93 ± 11.50 mg/dL). Endometrial glucose transporter 1 (GLUT1) transcript abundance was increased in pregnant heifers (P < 0.01) but was not different due to antral follicle number or the interaction. Therefore, differences in glucose concentrations associated with antral follicle number may be due to differences in GLUT1 transcription before d16 or due to differences in protein abundance or functionality. Taken together, heifers with increased number of antral follicles may have increased energy availability in the uterus for trophoblast proliferation and function. USDA is an equal opportunity provider and employer.
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Tisdall, D. J., N. Hudson, P. Smith, and K. P. McNatty. "Localization of ovine follistatin and α and βA inhibin mRNA in the sheep ovary during the oestrous cycle." Journal of Molecular Endocrinology 12, no. 2 (April 1994): 181–93. http://dx.doi.org/10.1677/jme.0.0120181.
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ABSTRACT The sites of follistatin and α and βA inhibin gene expression were examined by in situ hybridization in sheep ovaries during the early and mid-luteal phases (days 3 and 10) of the oestrous cycle and a prostaglandin F2α (PGF2α)-induced follicular phase. Follistatin mRNA was detected in the granulosa cells of preantral, antral and early atretic follicles at all stages of the oestrous cycle, and in the corpora lutea at the early and mid-luteal stages of the cycle. However, only low levels of expression of follistatin were observed in the presumptive preovulatory follicle at 56 h after treatment with PGF2α. Both α and βA inhibin were shown to be expressed in ovaries at all stages of the oestrous cycle. In situ hybridization localized α subunit mRNA to the granulosa cells of most, but not all, healthy antral follicles, and to no other ovarian cell type. In contrast, expression of the βA subunit was confined to a few medium-to-large healthy antral follicles. In antral follicles expressing βA inhibin, mRNAs for α inhibin and follistatin were always detected, but the converse was not true. Unlike follistatin, no α and βA inhibin expression was seen in preantral follicles, developing corpora lutea, or follicles undergoing atresia. These results show that, in the adult sheep ovary, follistatin gene expression is a constitutive event in all growing follicles from the early preantral stage, and also provide indirect evidence of the involvement of follistatin, but not inhibin or activin, in the early stages of ovarian follicle development in sheep.
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Dole, Gretchen, Eric E. Nilsson, and Michael K. Skinner. "Glial-derived neurotrophic factor promotes ovarian primordial follicle development and cell–cell interactions during folliculogenesis." REPRODUCTION 135, no. 5 (May 2008): 671–82. http://dx.doi.org/10.1530/rep-07-0405.
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Female fertility is determined in part by the size and development of the primordial follicle pool. The current study investigates the role of glial cell-line-derived neurotrophic factor (GDNF) in the regulation of primordial follicle development in the ovary. Ovaries from 4-day-old female rat pups were maintained in organ culture for 10 days in the absence (control) or presence of GDNF or kit ligand (KL)/stem cell factor. Ovaries treated with GDNF contained a significant increase in developing follicles, similar to that observed with KL treatment previously shown to promote follicle development. The actions of GDNF on the ovarian transcriptome were investigated with a microarray analysis. Immunohistochemical studies demonstrated that GDNF is localized to oocyte cytoplasm in follicles of all developmental stages, as well as to cumulus granulosa cells and theca cells in antral follicles. GDNF receptor α1 (GFRα1) staining was localized to oocyte cytoplasm of primordial and primary follicles, and at reduced levels in the oocytes of antral follicles. GFRα1 was present in mural granulosa cells of antral follicles, theca cells, and ovarian surface epithelium. The localization studies were confirmed with molecular analysis. Microarray analysis was used to identify changes in the ovarian transcriptome and further elucidate the signaling network regulating early follicle development. Observations indicate that GDNF promotes primordial follicle development and mediates autocrine and paracrine cell–cell interactions required during folliculogenesis. In contrast to the testis, ovarian GDNF is predominantly produced by germ cells (oocytes) rather than somatic cells.
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Nagashima, Jennifer, David E. Wildt, Alexander J. Travis, and Nucharin Songsasen. "Follicular size and stage and gonadotropin concentration affect alginate-encapsulated in vitro growth and survival of pre- and early antral dog follicles." Reproduction, Fertility and Development 29, no. 2 (2017): 262. http://dx.doi.org/10.1071/rd15004.
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Understanding stage-specific requirements of mammalian folliculogenesis is limited in the domestic dog. The present study examined the effects of two potential regulators of dog follicle growth and survival in vitro, namely the original stage of the follicle (i.e. preantral (≤230 µm diameter) vs early antral (diameter from >230 to ≤330 µm) and FSH and/or LH concentrations. After isolation and alginate encapsulation, follicles were cultured in 0, 1, 10 or 100 µg mL–1 FSH and 0, 1 or 10 ng mL–1 LH for 20 days. Regardless of stage, FSH promoted growth, but LH did the same only in the absence of FSH. Production of 17β-oestradiol and progesterone was detectable, indicating theca cell activity. The greatest growth occurred in preantral (mean (± s.d.) 61.4 ± 25.9%) versus antral (42.6 ± 20.3%) follicles, but neither developmental stage nor gonadotropin affected survival. Antrum detection was minimal due, in part, to antral collapse, and oocytes exhibited an increasingly pale appearance and chromatin degeneration over time. The results demonstrate that pre- and early antral stage dog follicles encapsulated in alginate grow significantly in vitro. However, because FSH and LH alone or in combination fail to promote antrum development, the next step is identifying factors that enhance antral expansion.
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Thongkittidilok, C., Y. Li, D. Wildt, and N. Songsasen. "137 DYNAMIC SHIFT IN CYTOPLASMIC LIPIDS IN CAT OOCYTES DURING OVARIAN FOLLICLE DEVELOPMENT." Reproduction, Fertility and Development 28, no. 2 (2016): 198. http://dx.doi.org/10.1071/rdv28n2ab137.
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Cytoplasmic lipids play key roles during oocyte and embryo development. However, there is little information on the changes in lipid types during intraovarian follicular and oocyte growth. Here, we used matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry to understand lipid composition in the cat oocyte during differing stages of folliculogenesis. Follicles at different developmental stages were mechanically isolated from cat ovaries within 4 h after routine ovariohysterectomy. Oocytes with granulosa cells were recovered from secondary (preantral stage, n = 387), early antral (<0.5 mm diameter, n = 177), small antral (0.5–1 mm, n = 144), and antral (>1 mm, n = 120) follicles, then subjected to lipid extraction and MALDI-TOF analysis (n = 3 replicates). Resulting mass spectra data were evaluated using MALDIquant in R package to eliminate baseline (background) and to identify peak values. The latter maximal values for each follicle stage were selected and subjected to principal component analysis to identify similarities and differences in mass spectra profile among oocytes from varying developmental stages. Peaks were compared to those calculated molecular formulae available in the Lipid MAP database. Error estimates were calculated using Excel (Microsoft Corp., Redmond, WA), and lipid species identification performed using Lipid MS Predict. Twenty-nine lipid species from six glycerophospholipids groups (glycerophosphates, PA; glycerophosphoserines, PS; glycerophosphoinositols, PI; glycerophosphoglycerols, PG; glycerophosphoinositol monophosphates, PIP; and glycerophosphoethanolamines, PE) were identified, 15 being found in more than 1 developmental stage. Two species in particular, [PI(29:4)+Na]+ and [PIP(23:0)+Na]+, were the most abundant lipids and were identified in oocytes from all developmental stages. There were dynamic shifts in lipid species expressed at different follicle stages. Oocytes from secondary and antral follicles contained more lipid types (15 and 22, respectively) than early (10) and small antral (4) counterparts. Four (PA, PS, PI, and PIP) of the 6 glycerophospholipids were found only in oocytes from secondary and antral follicles. Oocytes from small antral follicles also lacked PA, PS, and PG, whereas PG was not found in early antral stage oocytes. In summary, we showed for the first time in the cat that, similar to goats and rats, there are temporal changes in lipid types within the oocyte during folliculogenesis. We suspect that these changing dynamics, including shifts in presence or absence of lipid species with follicle stage, may be playing key roles in oocyte growth and viability. Our findings also serve as in vivo benchmarks for parallel studies focused on enhancing an in vitro culture system for early-stage ovarian follicles to preserve fertility of genetically valuable domestic and wild felids.
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van Cappellen, W. A., H. M. A. Meijs-Roelofs, P. Kramer, E. C. M. van Leeuwen, R. de Leeuw, and F. H. de Jong. "Recombinant FSH (Org32489) induces follicle growth and ovulation in the adult cyclic rat." Journal of Endocrinology 144, no. 1 (January 1995): 39–47. http://dx.doi.org/10.1677/joe.0.1440039.
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Abstract The effects of a single injection of recombinant human FSH (rhFSH; Org32489) on ovulation rate and timing and on antral follicle growth were studied in adult 5-day cyclic rats. Rats injected at 1700 h on dioestrus-2 with a dose of 10 IU rhFSH showed, on average, no increase in ovulation rate on the day of expected oestrus. However, an additional, precocious ovulation resulting in a normal number of corpora lutea 13·3±0·4, n=6) was found to take place on the night after injection, i.e. dioestrus-3. No mating behaviour, as shown by the absence of vaginal plugs the next morning, was observed at this ovulation. Follicle counts showed a loss of large antral follicles due to ovulation and increased numbers of healthy small antral follicles at 17 and 41 h after injection, indicating a decrease of atresia of growing follicles as well as additional recruitment of new antral follicles. The endogenous serum FSH concentration on the subsequent day of oestrus (65 h after the rhFSH injection) as well as recruitment of small antral follicles were lower in the rhFSH-treated rats than in saline-treated controls. The ovulation at oestrus, 48 h after the precocious, rhFSH-induced ovulation showed large differences in the number of oocytes between the rats in one treatment group. Similar results in terms of immediate ovulation induction were obtained by using a highly purified human urinary FSH preparation (i.e. metrodin). Furthermore, the direct induction of ovulation by rhFSH or metrodin could not be prevented by the injection of an LHRH antagonist. It was concluded that rhFSH can induce acute ovulation in rats, and stimulates follicular development directly or indirectly through increased FSH levels after ovulation. It induces antral follicle growth and decreases early atresia in small antral follicles. Journal of Endocrinology (1995) 144, 39–47
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Allan, C. M., Y. Wang, M. Jimenez, B. Marshan, J. Spaliviero, P. Illingworth, and D. J. Handelsman. "Follicle-stimulating hormone increases primordial follicle reserve in mature female hypogonadal mice." Journal of Endocrinology 188, no. 3 (March 2006): 549–57. http://dx.doi.org/10.1677/joe.1.06614.
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Ovarian primordial follicle reserve is considered hormonally independent or subject to depletion by FSH-driven follicle recruitment. To explore specific in vivo effects of FSH on early follicle populations in the absence of luteinizing hormone (LH) activity, we examined mature hypogonadal (hpg), gonadotrophin-deficient mice expressing transgenic (tg) human FSH. Sustained expression of tg-FSH (5.3 ± 0.3 IU/l) increased ovary weights fourfold and significantly elevated total primordial follicle numbers twofold in tg-FSH hpg (4209 ± 457) relative to non-tg hpg (2079 ± 391) and wild-type (2043 ± 195) age-matched ovaries. Absolute primary follicle numbers in tg-FSH hpg ovaries were similar to non-tg hpg and wild-type ovaries. Furthermore, tg-FSH quantitatively increased secondary and antral follicles in hpg ovaries to numbers equivalent to wild-type, but did not induce ovulation, indicating a selective FSH response without LH. Circulating inhibin B and inhibin A levels were significantly increased in tg-FSH hpg females compared with hpg controls, and inhibin B correlated with antral number, consistent with FSH-driven antral follicle formation. These findings revealed that sustained pituitary-independent FSH activity, in the absence of endogenous gonadotrophins, promotes an increase in primordial follicle reserve despite also stimulating follicular growth in mature females. Therefore, the tg-FSH hpg ovary presents a novel paradigm to evaluate specific gonadotrophin effects on follicle reserve and recruitment.
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Nation, A., and L. Selwood. "The production of mature oocytes from adult ovaries following primary follicle culture in a marsupial." REPRODUCTION 138, no. 2 (August 2009): 247–55. http://dx.doi.org/10.1530/rep-09-0028.
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A model marsupial culture system has been developed whereby individual primary follicles, obtained from adult ovaries, can be grown in vitro to the antral stage and oocytes retrieved from these follicles can achieve nuclear maturation (metaphase II) in the presence of LH. Primary follicles isolated from adult Sminthopsis macroura ovaries were cultured individually in one of four systems: microdrops under oil, upright, inverted, or roller culture. After 6 days of culture, cumulus–oocyte complexes (COCs) were excised from early antral follicles and incubated for an additional 24 h to assess meiotic competence and the effects of LH and lithium on oocyte maturation. Histology and transmission electron microscopy established normal in vivo standards and verified oocyte and follicular integrity following culture. On day 6 of culture, follicle viability was significantly greater in the inverted system (73%) than in the other three systems (10–46%). The inverted system was the most effective in supporting development with follicles demonstrating progressive growth during culture and showing antral signs by day 4. Meiotic resumption during COC culture was facilitated by LH, but hindered by lithium. The ability to resume meiosis and progress to metaphase II was equivalent in oocytes retrieved following follicle culture and those matured in vivo. This study highlights the importance of oxygen and nutrient availability during marsupial follicle culture, and demonstrates for the first time that primary follicles isolated from adult mammalian ovaries can undergo normal growth and development in vitro, to produce mature, meiotically competent oocytes.
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Sato, Yorino, Yuan Cheng, Kazuhiro Kawamura, Seido Takae, and Aaron J. W. Hsueh. "C-Type Natriuretic Peptide Stimulates Ovarian Follicle Development." Molecular Endocrinology 26, no. 7 (July 1, 2012): 1158–66. http://dx.doi.org/10.1210/me.2012-1027.
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Abstract C-type natriuretic peptide (CNP) encoded by the NPPC (Natriuretic Peptide Precursor C) gene expressed in ovarian granulosa cells inhibits oocyte maturation by activating the natriuretic peptide receptor (NPR)B (NPRB) in cumulus cells. RT-PCR analyses indicated increased NPPC and NPRB expression during ovarian development and follicle growth, associated with increases in ovarian CNP peptides in mice. In cultured somatic cells from infantile ovaries and granulosa cells from prepubertal animals, treatment with CNP stimulated cGMP production. Also, treatment of cultured preantral follicles with CNP stimulated follicle growth whereas treatment of cultured ovarian explants from infantile mice with CNP, similar to FSH, increased ovarian weight gain that was associated with the development of primary and early secondary follicles to the late secondary stage. Of interest, treatment with FSH increased levels of NPPC, but not NPRB, transcripts in ovarian explants. In vivo studies further indicated that daily injections of infantile mice with CNP for 4 d promoted ovarian growth, allowing successful ovulation induction by gonadotropins. In prepubertal mice, CNP treatment alone also promoted early antral follicle growth to the preovulatory stage, leading to efficient ovulation induction by LH/human chorionic gonadotropin. Mature oocytes retrieved after CNP treatment could be fertilized in vitro and developed into blastocysts, allowing the delivery of viable offspring. Thus, CNP secreted by growing follicles is capable of stimulating preantral and antral follicle growth. In place of FSH, CNP treatment could provide an alternative therapy for female infertility.
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Segers, Ingrid, Tom Adriaenssens, Sandra Wathlet, and Johan Smitz. "Gene expression differences induced by equimolar low doses of LH or hCG in combination with FSH in cultured mouse antral follicles." Journal of Endocrinology 215, no. 2 (August 20, 2012): 269–80. http://dx.doi.org/10.1530/joe-12-0150.
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In a natural cycle, follicle growth is coordinated by FSH and LH. Follicle growth stimulation in Assisted Reproductive Technologies (ART) requires antral follicles to be exposed to both FSH and LH bioactivity, especially after GNRH analog pretreatment. The main aim was to detect possible differences in gene expression in granulosa cells after exposing the follicle during antral growth to LH or hCG, as LH and hCG are different molecules acting on the same receptor. Effects of five gonadotropin treatments were investigated for 16 genes using a mouse follicle culture model. Early (day 6) antral follicles were exposed to high recombinant FSH combined or not with equimolar concentrations of recombinant LH (rLH) or recombinant hCG (rhCG) and to highly purified human menopausal gonadotropin (HP-hMG) for 6 h, 12 h, or 3 days. Expression differences were tested for genes involved in steroidogenesis:Mvk,Lss,Cyp11a1,Hsd3b1,Cyp19a1,Nr4a1, andTimp1; final granulosa differentiation:Lhcgr,Oxtr,Pgr,Egfr,Hif1a, andVegfa; and cytokines:Cxcl12,Cxcr4, andSdc4.Lhcgrwas present and upregulated by gonadotropins.Nr4a1,Cxcl12, andCxcr4showed a different expression pattern if LH bioactivity was added to high FSH in the first hours after exposure. However, no signs of premature luteinization were present even after a 3-day treatment as shown byCyp19a1,Oxtr,Pgr, andEgfrand by estrogen and progesterone measurements. The downstream signaling by rhCG or rLH through the LHCGR was not different for this gene selection. Granulosa cells from follicles exposed to HP-hMG showed an enhanced expression level for several genes compared with recombinant gonadotropin exposure, possibly pointing to enhanced cellular activity.
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Palma, Gustavo Adolfo, Martin Eduardo Argañaraz, Antonio Daniel Barrera, Daniela Rodler, Adrian Ángel Mutto, and Fred Sinowatz. "Biology and Biotechnology of Follicle Development." Scientific World Journal 2012 (2012): 1–14. http://dx.doi.org/10.1100/2012/938138.
Full textAbstract:
Growth and development of ovarian follicles require a series of coordinated events that induce morphological and functional changes within the follicle, leading to cell differentiation and oocyte development. The preantral early antral follicle transition is the stage of follicular development during which gonadotropin dependence is obtained and the progression into growing or atresia of the follicle is made. Follicular growth during this period is tightly regulated by oocyte-granulosatheca cell interactions. A cluster of early expressed genes is required for normal folliculogenesis. Granulosa cell factors stimulate the recruitment of theca cells from cortical stromal cells. Thecal factors promote granulosa cell proliferation and suppress granulosa cell apoptosis. Cell-cell and cell-extracellular matrix interactions influence the production of growth factors in the different follicular compartments (oocyte, granulosa, and theca cells). Several autocrine and paracrine factors are involved in follicular growth and differentiation; their activity is present even at the time of ovulation, decreasing the gap junction communication, and stimulating the theca cell proliferation. In addition, the identification of the factors that promote follicular growth from the preantral stage to the small antral stage may provide important information for the identification for assisted reproduction techniques.
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Rodgers, R. J., and H. F. Irving-Rodgers. "Morphological classification of bovine ovarian follicles." REPRODUCTION 139, no. 2 (February 2010): 309–18. http://dx.doi.org/10.1530/rep-09-0177.
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Follicle classification is an important aid to the understanding of follicular development and atresia. Some bovine primordial follicles have the classical primordial shape, but ellipsoidal shaped follicles with some cuboidal granulosa cells at the poles are far more common. Preantral follicles have one of two basal lamina phenotypes, either a single aligned layer or one with additional layers. In antral follicles <5 mm diameter, half of the healthy follicles have columnar shaped basal granulosa cells and additional layers of basal lamina, which appear as loops in cross section (‘loopy’). The remainder have aligned single-layered follicular basal laminas with rounded basal cells, and contain better quality oocytes than the loopy/columnar follicles. In sizes >5 mm, only aligned/rounded phenotypes are present. Dominant and subordinate follicles can be identified by ultrasound and/or histological examination of pairs of ovaries. Atretic follicles <5 mm are either basal atretic or antral atretic, named on the basis of the location in the membrana granulosa where cells die first. Basal atretic follicles have considerable biological differences to antral atretic follicles. In follicles >5 mm, only antral atresia is observed. The concentrations of follicular fluid steroid hormones can be used to classify atresia and distinguish some of the different types of atresia; however, this method is unlikely to identify follicles early in atresia, and hence misclassify them as healthy. Other biochemical and histological methods can be used, but since cell death is a part of normal homoeostatis, deciding when a follicle has entered atresia remains somewhat subjective.
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Fowler, Paul A., and Norah Spears. "The cultured rodent follicle as a model for investigations of gonadotrophin surge-attenuating factor (GnSAF) production." Reproduction 127, no. 6 (June 2004): 679–88. http://dx.doi.org/10.1530/rep.1.00141.
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Gonadotrophin surge-attenuating factor (GnSAF) bioactivity (the suppression of GnRH-induced but not basal LH and FSH secretion from pituitary gonadotrophs) is produced by granulosa cells in vitro. Previous studies to investigate this bioactivity used dispersed granulosa cells which lack some cell types and the structural components of the follicle in vivo. The aim of this study, therefore, was to investigate whether intact rodent follicle culture was a suitable model for the study of the production of GnSAF bioactivity, allowing GnSAF to be investigated in a more physiologically realistic environment while still retaining culture conditions from which, as with granulosa cell cultures, extraneous factors can be excluded. Follicles from 16-day-old rats and 21-day-old mice were cultured for 3–6 days in the presence or absence of FSH and/or LH. The follicle-conditioned medium, and matching samples of unconditioned culture medium were added to our established rat pituitary monolayer GnSAF bioassay. Both mouse and rat intact follicles produced GnSAF bioactivity, reducing GnRH-induced LH secretion significantly. GnSAF output from the mouse follicles was highest during days 1–3 of culture, when follicles were at an early antral stage of development, and fell on days 4–6 as the follicles grew to the mid antral stage. While the stimulatory effects of FSH on rat follicle GnSAF secretion was dose-dependent, LH alone did not increase GnSAF production. An antibody against human GnSAF blocked GnSAF bioactivity produced by rat follicles, and recognised proteins within the expected pI and molecular weight range for GnSAF in two-dimensional gels of rat follicle-conditioned medium, showing a good homology between rodent and human GnSAF proteins. In conclusion, the release of GnSAF bioactivity is principally from small follicles stimulated by FSH. Therefore, intact rodent follicle culture systems offer an excellent model for the investigation of factors controlling GnSAF production under relatively physiological conditions.
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Hornick, J. E., F. E. Duncan, L. D. Shea, and T. K. Woodruff. "Multiple follicle culture supports primary follicle growth through paracrine-acting signals." REPRODUCTION 145, no. 1 (January 2013): 19–32. http://dx.doi.org/10.1530/rep-12-0233.
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In vitro follicle growth in alginate hydrogels is a unique and versatile method for studying ovarian and follicle biology that may also have implications for fertility preservation. Current culture systems support the development of isolated mouse follicles from the secondary stage onward. However, it has been a challenge to grow smaller follicles in vitro due to the dissociation of the oocyte from companion somatic cells. Recent work has demonstrated that coculturing primary follicles with mouse embryonic fibroblasts or ovarian stromal cells supports follicle survival and growth. In this study, we demonstrate that follicles themselves can exert a beneficial coculture effect. When primary follicles were cultured in groups of five or ten (multiple follicle culture), there was increased growth and survival. The multiple follicle culture approach maintained follicle integrity and resulted in the formation of antral stage follicles containing meiotically competent gametes. The growth and survival of primary follicles were highly number dependent, with the most significant enhancement observed when the largest number of follicles was grown together. Our data suggest that the follicle unit is necessary to produce the secreted factors responsible for the supportive effects of multiple follicle culture, as neither denuded oocytes, oocyte-secreted factors, nor granulosa cells alone were sufficient to support early follicle growth in vitro. Therefore, there may be signaling from both the oocyte and the follicle that enhances growth but requires both components in a feedback mechanism. This work is consistent with current in vivo models for follicle growth and thus advances the movement to recapitulate the ovarian environment in vitro.
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Keightley, R. A., B. Nixon, S. D. Roman, D. L. Russell, R. L. Robker, and E. A. McLaughlin. "509. REGULATING MURINE FOLLICLE DEVELOPMENT BY STIMULATION OF THE JAK2/STAT3 SIGNAL TRANSDUCTION PATHWAY." Reproduction, Fertility and Development 21, no. 9 (2009): 108. http://dx.doi.org/10.1071/srb09abs509.
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Follicular development requires the recruitment of primordial follicles into the growing follicle pool following initiation of multiple cytokine signalling pathways. Suppression of follicular development is thought to be key to maintaining the population of primordial follicles and allowing for controlled release of these follicles throughout the reproductive lifespan of the female. However, little is known of the processes and signalling molecules that suppress primordial follicle activation and early follicle growth. Our group has identified significant upregulation of the Janus Kinase 2 (JAK2)/ Signal Transducer and Activator of Transcription 3 (STAT3) signalling pathway inhibitor the Suppressor of Cytokine Signalling 4 (SOCS4) that coincides with the initial wave of follicular activation in theneonatal mouse ovary. Further studies by our group have localised the SOCS4 protein to the granulosa cells of activating and growing follicles, suggesting SOCS4 expression may be linked to follicular activation. We have focused on examining protein localisation and gene expression patterns of the eight SOCS family members CIS and SOCS1-7. We have recently demonstrated that co-culture of neonatal ovaries with Kit Ligand (KL) for 2 days increases the mRNA levels of all SOCS genes. We also demonstrated the co-localisation of SOCS2 proteins with the KL receptor c-kit in the mural granulosa cells of antral, and large pre-antral follicles suggesting a significant role for SOCS2 in the later stages of follicular development. We have also shown that culturing ovaries with the potent JAK2 inhibitor AG490 substantially reduces mRNA levels of all SOCS and STAT genes that we have so far measured. We hypothesise a significant role for JAK2/STAT3 signalling in promoting the activation and early growth of ovarian follicles. Our investigations have identified significant roles for JAK2/STAT3 and the SOCS family in the regulation of ovarian follicle development.
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Stansfield, F. J., J. O. Nöthling, and W. R. Allen. "The progression of small-follicle reserves in the ovaries of wild African elephants (Loxodonta africana) from puberty to reproductive senescence." Reproduction, Fertility and Development 25, no. 8 (2013): 1165. http://dx.doi.org/10.1071/rd12296.
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This study aimed to determine whether the follicle reserve in the ovary of the African elephant declines progressively after puberty and whether its depletion constrains the fertility of older females. Elephant ovaries were fixed in 4% neutral buffered formalin and small-follicle counts made using stereological protocols. Excepting a slight rise in small-follicle numbers between 16 and 25 years of age, there was a trend for follicle numbers to fall from puberty to 70 years. Reproductive status did not impact significantly on small-follicle numbers (P = 0.31). The number of early primary follicles, initially higher in number than true primary follicles, fell from post-puberty to nil at 45 years of age. Six of the seven oldest animals in the study showed signs of recent ovarian activity in the form of antral follicles, corpora lutea or large corpora nigra. The four oldest elephants (mean age 69 years) had a median small-follicle count of 11 113. In summary, it appears that the elephant ovary is capable of supplying oocytes for ovulation right up to the time of death at the age of maximum life expectancy, although the follicle reserve becomes depleted in some older elephants.
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Cushman, Robert A. "80 Randel Lectureship: Practical Applications for Developmental Programming of the Bovine Ovary." Journal of Animal Science 100, Supplement_1 (March 8, 2022): 29–30. http://dx.doi.org/10.1093/jas/skac028.057.
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Abstract Mammalian females are born with a finite supply of follicles within their ovaries that may be related to fertility and reproductive longevity. The number of microscopic follicles in the ovarian cortex is positively correlated to the number of antral follicles. In cattle, the number of antral follicles can be determined by ultrasonographic examination of the ovaries, is repeatable within a female, and has a moderate heritability. Studies in rodents suggest that nutritional status early in life can alter structure and function of the ovarian reserve, resulting in changes in follicle numbers, estrous cycle parameters, and reproductive longevity. This raises questions about how early life events might influence the ovarian reserve and reproductive performance in bovine females. A central hypothesis of our research is that the number of follicles that a heifer has when entering her first breeding season is influenced by external factors such as maternal nutrition during pregnancy, maternal stress during pregnancy, peri-pubertal nutrition, and health events. Understanding how these factors influence the structure and function of the ovarian reserve in replacement heifers may allow us to translate this knowledge into management practices that developmentally program the bovine ovary prior to the first breeding season to improve reproductive performance in the cow herd. Accomplishing this is made difficult because our understanding of the mechanisms controlling pre-antral follicle development in cattle is limited and growth of pre-antral follicles is occurring at the microscopic level within the ovarian cortex where it is difficult to monitor changes in real time. There has been some success, but variation in response across studies indicates that further research to understand the causes of this variation is required before we will be able to apply developmental programming in beef production systems to improve ovarian function in replacement heifers. USDA is an equal opportunity provider and employer.
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Torres-Rovira, Laura, Antonio Gonzalez-Bulnes, Sara Succu, Antonio Spezzigu, Maria E. Manca, Giovanni G. Leoni, Marina Sanna, et al. "Predictive value of antral follicle count and anti-Müllerian hormone for follicle and oocyte developmental competence during the early prepubertal period in a sheep model." Reproduction, Fertility and Development 26, no. 8 (2014): 1094. http://dx.doi.org/10.1071/rd13190.
Full textAbstract:
Circulating anti-Müllerian hormone (AMH) and antral follicle count (AFC) are addressed as suitable markers of oocyte quantity and quality during adulthood. To investigate whether AFC and circulating AMH could predict follicle development and oocyte quality during the prepubertal period we used 40-day-old ewe lambs with high, intermediate and low AFC (≥30, 16–29 and ≤15 follicles respectively). The analysis of the response to the exogenous FSH ovarian reserve test showed a positive correlation between AFC, AMH plasma levels, total follicle number and the number of large follicles (≥3 mm) grown after exogenous FSH administration. The incorporation of abattoir-derived oocytes collected from ovaries with different AFC in an in vitro embryo production system showed that a high AFC can predict oocyte quality in prepubertal ovaries, reflecting an ovarian status suitable for follicular development. The histological quantification of the ovarian reserve evidenced that AFC was not predictive of differences in either the number of healthy follicles or the size of the primordial follicle pool in prepubertal ovaries. Further studies are needed to investigate the implication on the reproductive performance of the significant inter-individual differences found in the present study in AFC and circulating AMH in the early prepubertal period.
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Clark, L. J., H. F. Irving-Rodgers, A. M. Dharmarajan, and R. J. Rodgers. "206.Cell death of the theca interna during bovine ovarian follicular atresia." Reproduction, Fertility and Development 16, no. 9 (2004): 206. http://dx.doi.org/10.1071/srb04abs206.
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It is generally accepted that death of cells within the theca interna occurs late during ovarian follicular atresia. Histological classifications of atresia are usually based solely upon the morphology of the membrana granulosa. Atresia of bovine antral follicles less than 5 mm in diameter has been redefined as either antral or basal atresia depending on where in the membrana granulosa cell death is initiated. The aim of present study was to investigate changes within the theca interna during both antral and basal atresia. Bovine ovaries were collected and processed for light microscopy and immunohistochemistry. Each follicle less then 5 mm was classified as either healthy, antral atretic or basal atretic, with antral atresia being further classified either early-mid or late stage. Sections were labelled by TUNEL to identify dead cells combined with lectin from Bandeiraea simplificifolia to identify endothelial cells or with an antibody to cytochrome P450 cholesterol side-chain cleavage to identify steroidogenic cells. The numerical density of steroidogenic cells within the theca interna was significantly reduced (P < 0.001) in basal atretic follicles compared to healthy and antral atretic follicles. In both antral and basal atresia there was death of endothelial cells and steroidogenic cells. However cell death was greater in endothelial cells (P < 0.05) and steroidogenic cells (P < 0.001) of the theca interna of basal atretic follicles. There was no significant difference in the amount of cell death in the membrana granulosa between early-mid antral atresia and basal atresia while death of the membrana granulosa was significantly increased in late antral atresia compared to basal atresia (P < 0.01). Therefore we conclude that basal atresia is not a progression of antral atresia and that the theca interna can be susceptible to cell death early in atresia in basal atretic follicles.
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Chen, T. Y., P. Stott, R. Z. Athorn, E. G. Bouwman, and P. Langendijk. "Undernutrition during early follicle development has irreversible effects on ovulation rate and embryos." Reproduction, Fertility and Development 24, no. 6 (2012): 886. http://dx.doi.org/10.1071/rd11292.
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This study assessed carry-over effects of energy level during the early antral phase and subsequent follicular phase on follicle recruitment and ovulation rate. Gilts (n = 45) were fed a standard diet to a low (L, ~1.2 kg day–1) or high (H, ~2.7 kg day–1) level during the early antral (luteal) phase, and subsequently fed a H or L feed level during the follicular phase, resulting in four treatment groups (HH, HL, LH and LL). Follicle size at the end of the luteal phase was greater for gilts fed a high feed level previously (3.3 vs 3.0 mm; P < 0.05). During the follicular phase, high feeding increased follicle size at Day 5 (6.9 vs 6.2 mm; P < 0.005) and plasma oestradiol concentration (P < 0.05). Nevertheless, a low feed level during the luteal phase reduced ovulation rate (14.4 vs 13.2; P < 0.05) and embryo number (12.6 vs 10.5; P < 0.05), and this was not counteracted by feed level during the follicular phase. Plasma progesterone concentration after ovulation was lower for LL gilts than for other treatments (P < 0.05). These results indicate that undernutrition during early antral follicle development may have a residual effect on follicle recruitment and quality.
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Uzumcu, Mehmet, Peter E. Kuhn, Jason E. Marano, AnnMarie E. Armenti, and Lisa Passantino. "Early postnatal methoxychlor exposure inhibits folliculogenesis and stimulates anti-Mullerian hormone production in the rat ovary." Journal of Endocrinology 191, no. 3 (December 2006): 549–58. http://dx.doi.org/10.1677/joe.1.06592.
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Methoxychlor [1,1,1-trichloro-2,2-bis(4-methoxyphenyl) ethane; MXC] is a chlorinated hydrocarbon pesticide commonly used in the United States as a replacement for DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane]. While MXC is a weak estrogenic compound, its more active, major metabolite [2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane; HPTE] shows estrogenic, anti-estrogenic, or anti-androgenic properties depending on the receptor subtype with which it interacts. Anti-Mullerian hormone (AMH) is a paracrine factor that suppresses initial follicle recruitment in the ovary. Studies have shown the effects of exposure to MXC on adult ovarian morphology and function. However, the effect of exposure to MXC at an early postnatal stage on pre-pubertal follicular development and ovarian AMH production has not been studied. Around postnatal day (P) 4, most of the primordial follicular assembly in rats is complete, and a large number of primordial follicles transition into the primary follicle stage, a process that is inhibited by estrogen. The objective of this study was to examine the effect of early postnatal (P3–P10) MXC exposure on ovarian morphology and size, follicle number, and AMH production in the pre-pubertal (P20) rat ovary and to investigate the effect of HPTE on AMH production in immature rat granulosa cells in vitro. Female rats were injected (s.c.) daily with vehicle (control) or 1, 10, 50, 100, or 500 mg MXC/kg per day (referred to here as 1MXC, 10MXC, and so forth.) between P3 and P10. On P20, uterine and ovarian weights were determined, ovarian histology was examined, and follicles were counted and classified into primordial, primary, secondary, pre-antral, or antral stages using the two largest serial sections at the center of the ovary. Ovarian AMH production was examined using immunohistochemistry and western blot analysis. The effect of HPTE (0.5–25 μM) on AMH production in cultured immature rat granulosa cells was determined by western blot analysis. Ovarian weight was reduced by 50, 100, and 500MXC (P < 0.01). MXC treatment inhibited folliculogenesis. Both 100 and 500MXC had a reduced number of antral follicles (P < 0.05) with a concomitant increase in pre-antral follicles (P < 0.05). Follicle numbers were not significantly affected by 1, 10, or 50MXC. Total follicle number and the number of primordial, primary, or secondary stage follicles were not significantly different in all treatment groups. Immunohistochemistry showed that MXC-treated ovaries had more AMH-positive follicles with stronger AMH immunostaining. Western blot analysis showed that AMH production was 1.6 ± 0.2, 1.85 ± 0.6, and 2.2 ± 0.5 times higher in the 50, 100, and 500MXC ovaries as compared with the control ovaries respectively (P < 0.05). Granulosa cells treated with 1 or 5 μM HPTE had significantly greater AMH production (P < 0.05). These results demonstrate that MXC inhibits early ovarian development and stimulates AMH production directly in the rat ovary. In addition, HPTE was shown to stimulate AMH production in rat granulosa cells. Endocrine disruptors are widespread in the environment, and MXC represents a model endocrine disruptor due to the multiple actions of its metabolites. This study confirms that the endocrine disruptor MXC inhibits follicular development and demonstrates for the first time that MXC and HPTE directly stimulate AMH productionin the ovary. Thisnovel finding suggests that elevated AMH may play a role in MXC’s inhibitory effect in the ovary.
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Akymyshyn, M. M., N. N. Kuzmina, and D. D. Ostapiv. "Активність та вміст ізозимів аспартатамінотрансферази в репродуктивних органах корів." Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 19, no. 77 (March 5, 2017): 27–31. http://dx.doi.org/10.15421/nvlvet7707.
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Activity and isozyme content of aspartate transaminase in cow reproductive organs at different physiological states and ovarian hypofunction were studied. It was registered, that activity of aspartate transaminase (AST) in ovarian tissue and endometrium at corpus luteum state is 132.0 ± 8.23 and 172.9 ± 8.70 μm/min×mg of protein, lower on 26.3 and 5.5% at follicle growth and at early corpus luteum is 66.5 ± 2.10 and 147.1 ± 13.26 μm/min×mg of protein. Lowest AST activity is registered at hypofunction state (61.8 ± 4.57 і 146.1 ± 9.33 μm/min×mg of protein). In cow reproductive organ tissues and antral fluid from ovarian follicles was registered two bands of proteins, that have AST activity. In reproductive organs main part is mitochondrial isozyme (АSТ2; 78.8–97.7%) in antral fluid – cytosole (АSТ1; 72.8–88.2%). In ovarian and uterus tissues was established high enzyme activity at late corpus luteum, that characterizes intensive aspartate conversion to oxaloacetate and possible utilization of substeates to maintain energetic and sytnthetic needs in cow reproductive organs. Antral fluid of big follicles from ovarian at follicle growth and at state of late corpus luteum characterizes by high activity and content of AST, that points on follicle cell growth – granulose and oocyte. In ovarian tissue and endometrium at hypofunction lower activity and isozyme content point on substrate deficiency for transamination and violation of physiological functions.
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Brown, H. M., M. Pritchard, and D. L. Russell. "225. Early ovarian follicle dysgenesis in a disintegrin and metalloproteinase with thrombospondin motifs type 1 (ADAMTS-1) null mice." Reproduction, Fertility and Development 17, no. 9 (2005): 87. http://dx.doi.org/10.1071/srb05abs225.
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ADAMTS-1 is a multi-domain, multi-functional matrix metalloproteinase expressed in the mouse ovary during folliculogenesis and ovulation. Adult ADAMTS-1 null female mice are infertile; however, the exact mechanism responsible for their reproductive failure is yet to be explained. ADAMTS-1 null ovaries prior to and following ovulation were examined and a defect in ovarian follicle development was identified. A classification system was devised and used to identify morphological differences between normal and ADAMTS-1 null ovaries. The phenotype indicated a progressive loss of follicle structural integrity ranging from a slight loss of shape, to full structural dysgenesis. As a result, large numbers of oocytes with healthy appearance were found with no surrounding follicle structure. The numbers of preantral follicles was not altered, but type 6 (early antral) follicles in the ADAMTS-1 null ovaries were significantly reduced (P < 0.05) when compared to wild-type ovaries suggesting initiation of follicular degeneration coincident with antrum formation. There was also a significant decrease (P < 0.05) in the number of periovulatory follicles (type 7 and 8) in the ADAMTS-1 null ovaries. This suggests that late folliculogenesis, in the period of rapid growth and expansion is disrupted when ADAMTS-1 is not present and results in fewer follicles available for ovulation. Further, we have demonstrated that the active form of ADAMTS-1 is present in the thecal-granulosa boundary of the ovarian follicle suggesting a role in extracellular matrix remodeling at this boundary during follicle growth. Analyses of the basement membrane at this boundary both in growing and ovulating follicles indicate that ECM remodeling in this region is indeed disrupted. These data demonstrate that remodeling of surrounding structural matrix is crucial to follicle growth and structural integrity. Functional ADAMTS-1 is important for matrix remodeling during the growth of the follicle, particularly during antrum formation.
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Yuan, Wei, and Linda C. Giudice. "Programmed Cell Death in Human Ovary Is a Function of Follicle and Corpus Luteum Status*." Journal of Clinical Endocrinology & Metabolism 82, no. 9 (September 1, 1997): 3148–55. http://dx.doi.org/10.1210/jcem.82.9.4191.
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Abstract Although extensive investigation on follicular apoptosis (programmed cell death) has been conducted in the infraprimate ovary, there is little information regarding apoptosis and its relationship to follicular status in the human. In this study, apoptosis was investigated in 116 human ovarian follicles (primordial to dominant) and 5 corpora lutea from a total of 27 premenopausal women. Follicles and corpora lutea were evaluated for the presence of DNA fragmentation, characteristic of apoptosis, by two methods: in situ hybridization using 3′ end-labeling of DNA with digoxigenin-labeled nucleotides and subsequent digoxigenin antibody and peroxidase staining, and/or biochemical analysis of low molecular weight DNA laddering. Follicle functional status was evaluated by determining follicle sizes and follicular fluid androgen/estrogen (A/E) ratios. No apoptosis was observed in 67 primordial, primary, or secondary follicles. Positive staining for DNA fragmentation was found in a few granulosa cells in 0.1- to 2-mm follicles, whereas abundant staining in granulosa was detected in 2.1- to 9.9-mm follicles. In contrast, no DNA fragmentation was detected in dominant follicles (10–16 mm). The frequency of apoptosis in follicles was calculated to be 37% in 0.1- to 2-mm follicles, 50% in 2.1- to 5-mm follicles, and 27% in 5.1- to 9.9-mm follicles. Abundant low molecular weight DNA laddering was only found in androgen-dominant follicles and not in estrogen-dominant follicles. Positive staining for DNA fragmentation and low molecular weight DNA laddering were observed in degenerating but not healthy-appearing corpora lutea. In the former, DNA fragmentation was found primarily in large luteal cells. These data suggest that follicular atresia in human ovary results from normal programmed cell death and primarily occurs in the granulosa cell layers of the early antral and <10-mm antral follicles primarily. Furthermore, because apoptosis occurs as early as the 200-mm stage, follicle selection may begin as early as the initial formation of the antrum. The results also suggest that degeneration of the corpus luteum occurs by apoptotic mechanisms.
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Pankhurst, Michael W., Rebecca L. Kelley, Rachel L. Sanders, Savana R. Woodcock, Dorothy E. Oorschot, and Nicola J. Batchelor. "Anti-Müllerian hormone overexpression restricts preantral ovarian follicle survival." Journal of Endocrinology 237, no. 2 (May 2018): 153–63. http://dx.doi.org/10.1530/joe-18-0005.
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Anti-Müllerian hormone (AMH) is an ovarian regulator that affects folliculogenesis. AMH inhibits the developmental activation of the dormant primordial follicles and the oocyte within. In more mature follicles, AMH reduces granulosa cell sensitivity to follicle-stimulating hormone (FSH). We examined the effects of AMH overexpression on the stages of ovarian folliculogenesis, and the development of embryos, with a transgenic mouse that overexpresses human AMH in central nervous system neurons under the control of the mouse Thy1.2 promoter (Thy1.2-AMH Tg mice). These mice are severely sub-fertile, despite relatively normal ovulation rates. The embryos of Thy1.2-AMHTg females exhibited delayed preimplantation development and extensive mid-gestation fetal resorption. Young Thy1.2-AMHTg mouse ovaries exhibited only a slight reduction in the rate of primordial follicle activation but large declines in the number of developing follicles surviving past the primary stage. It was expected that Thy1.2-AMHTg mice would retain more primordial follicles as they aged, but at 5 months, their number was significantly reduced relative to wild-type females. These data indicate that moderate elevations in AMH levels can severely restrict reproductive output and the number of developing follicles in the ovary. This evidence suggests that early antral follicles are a target for AMH signaling, which may regulate early follicle survival.
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Binelli, Mario, and Bruce D. Murphy. "Coordinated regulation of follicle development by germ and somatic cells." Reproduction, Fertility and Development 22, no. 1 (2010): 1. http://dx.doi.org/10.1071/rd09218.
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The continuum of folliculogenesis begins in the fetal ovary with the differentiation of the oogonia and their isolation within the primordial follicles. Primordial follicle activation is an enigmatic process, whereby some follicles enter the growing pool to become primary follicles, thereby embarking on an irreversible progression towards ovulation or atresia. This process is under the coordinated regulation of factors from the oocyte itself, as well as from the somatic cells of the ovary, in particular the theca and granulosa cells, which are structural components of the follicle. These two influences provide the principal stimuli for the growth of the follicle to the late preantral or early antral stage of development. The endocrine effects of the gonadotrophins FSH and LH are essential to the continued progression of the follicle and most atresia can be attributed to the failure to receive or process the gonadotrophin signals. The peri-ovulatory state has received intensive investigation recently, demonstrating a coordinated role for gonadotrophins, steroids, epidermal growth factor family proteins and prostaglandins. Thus, a complex programme of coordinated interaction of governing elements from both germ and somatic cell sources is required for successful follicle development.
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Hohmann, Femke P., Joop S. E. Laven, Frank H. de Jong, and Bart C. J. M. Fauser. "Relationship between inhibin A and B, estradiol and follicle growth dynamics during ovarian stimulation in normo-ovulatory women." European Journal of Endocrinology 152, no. 3 (March 2005): 395–401. http://dx.doi.org/10.1530/eje.1.01871.
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Objective: To investigate the relationship between serum concentrations of inhibin A, inhibin B and estradiol (E2) and the number of developing follicles during the administration of exogenous follicle-stimulating hormone (FSH) in various regimens in normo-ovulatory volunteers and to evaluate if inhibins act as suitable markers for the number of developing follicles during ovarian stimulation. Design and methods: Serial hormone determinations and assessment of follicle numbers were carried out during unstimulated cycles and during various interventions with exogenous FSH. Subjects were randomized for FSH administration into the following groups: a single high dose (375 IU) during the early follicular phase (group A), 5 consecutive low doses (75 IU/day) starting in the mid follicular phase (group B) or daily low doses (75 IU/day) during the early to late follicular phase (starting on cycle days 3, 5 or 7; groups C, D and E respectively). Results: Extending the FSH window increases the number of small antral follicles and hence inhibin B serum concentrations. If such an intervention results in multi-follicular growth, mid follicular phase inhibin B (P = 0.001) as well as late follicular phase inhibin B and inhibin A levels are significantly (P < 0.05 and P < 0.01 respectively) increased compared with mono-follicular cycles or the natural cycle. Although mid follicular inhibin B levels correlated well with the number of small antral (P < 0.05) and pre-ovulatory (P < 0.001) follicles in the late follicular phase, mid follicular inhibin A and estradiol serum concentrations only correlated with the number of pre-ovulatory follicles (P < 0.001 and P < 0.01 respectively). Conclusions: The present data extend our understanding of the relationship between follicle dynamics, serum inhibins and FSH during ovarian hyperstimulation. However, although mid follicular inhibin B does correlate with the number of developing follicles, it does not facilitate the identification of women at risk for multiple follicle development.
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Moor, R. M., C. Lee, Y. F. Dai, and J. Fulka. "Antral follicles confer developmental competence on oocytes." Zygote 4, no. 04 (November 1996): 289–93. http://dx.doi.org/10.1017/s0967199400003269.
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This paper addresses the proposition, first advanced by Wilson (1925), that successful embryogenesis depends on an ordered series of events in oogenesis. It is at the completion of this varied set of intracellular changes that the oocyte finally acquires its full capacity to support fertilisation and development. Amongst the earliest nuclear events are those associated with chromosome pairing and meiotic recombination. During the growth phase cell volume increases 300-fold and the cytoplasm becomes the storage site for RNA and protein which will be mobilised during early development. Finally, a short phase of intracellular reprogramming, or maturation, completes the series of events during oogenesis that confer developmental competence upon the oocyte. Follicle cell support is an indispensable requirement for ordered oocyte development and provides the early germline cell with many of the essential nutrients and growth regulators required to ensure progression through the protracted growth phase (see contributions by Cecconi & Rosella and De Feliciet al.this issue). Although different, the interactions between the full-grown oocyte and the antral follicle are no less crucial to the acquisition of competence than those involved in the earlier stages of oogenesis.
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Thurston, L. M., D. R. E. Abayasekara, and A. E. Michael. "11β-Hydroxysteroid dehydrogenase expression and activities in bovine granulosa cells and corpora lutea implicate corticosteroids in bovine ovarian physiology." Journal of Endocrinology 193, no. 2 (May 2007): 299–310. http://dx.doi.org/10.1677/joe.1.07025.
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Cortisol–cortisone metabolism is catalysed by the bi-directional NADP(H)-dependent type 1 11β-hydroxysteroid dehydrogenase (11βHSD1) enzyme and the oxidative NAD+-dependent type 2 11βHSD (11βHSD2). This study related the expression of 11βHSD1 and 11βHSD2 enzymes (mRNA and protein) to net 11-ketosteroid reductase and 11β-dehydrogenase (11β-DH) activities in bovine follicular granulosa and luteal cells. Granulosa cells were isolated from follicles of < 4, 4–8, > 8 and > 12 mm in diameter in either the follicular or luteal phase of the ovarian cycle. Luteal cells were obtained from corpora lutea (CL) in the early non-pregnant luteal phase. Enzyme expression was assessed by reverse transcription-PCR and western blotting, while enzyme activities were measured over 1 h in cell homogenates using radiometric conversion assays with 100 nM [3H]cortisone or [3H]cortisol and pyridine dinucleotide cofactors. Irrespective of follicle diameter, the expression of 11βHSD2 and NAD+-dependent oxidation of cortisol predominated in granulosa cells harvested in the follicular phase. In contrast, in granulosa cells obtained from luteal phase follicles and in bovine luteal cells, expression of 11βHSD1 exceeded that of 11βHSD2 and the major enzyme activity was NADP+-dependent cortisol oxidation. Increasing follicular diameter was associated with progressive increases in expression and activities of 11βHSD2 and 11βHSD1 in follicular and luteal phase granulosa cells respectively. In follicular phase granulosa cells from antral follicles < 12 mm, 11βHSD1 migrated with a molecular mass of 34 kDa, whereas in the dominant follicle, CL and all luteal phase granulosa cells, a second protein band of 68 kDa was consistently detected. In all samples, 11βHSD2 had a molecular mass of 48 kDa, but in large antral follicles (> 8 mm), there was an additional immunoreactive band at 50 kDa. We conclude that 11βHSD2 is the predominant functional 11βHSD enzyme expressed in follicular phase granulosa cells from growing bovine antral follicles. In contrast, in bovine granulosa cells from dominant or luteal phase follicles, and in bovine luteal cells from early non-pregnant CL, 11βHSD1 is the major glucocorticoid-metabolising enzyme. The increasing levels of cortisol inactivation by the combined NADP+- and NAD+-dependent 11β-DH activities suggest a need to restrict cortisol access to corticosteroid receptors in the final stages of follicle development.
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Vo, Kim Cat Tuyen, and Kazuhiro Kawamura. "In Vitro Activation Early Follicles: From the Basic Science to the Clinical Perspectives." International Journal of Molecular Sciences 22, no. 7 (April 6, 2021): 3785. http://dx.doi.org/10.3390/ijms22073785.
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Development of early follicles, especially the activation of primordial follicles, is strictly modulated by a network of signaling pathways. Recent advance in ovarian physiology has been allowed the development of several therapies to improve reproductive outcomes by manipulating early folliculogenesis. Among these, in vitro activation (IVA) has been recently developed to extend the possibility of achieving genetically related offspring for patients with premature ovarian insufficiency and ovarian dysfunction. This method was established based on basic science studies of the intraovarian signaling pathways: the phosphoinositide 3-kinase (PI3K)/Akt and the Hippo signaling pathways. These two pathways were found to play crucial roles in folliculogenesis from the primordial follicle to the early antral follicle. Following the results of rodent experiments, IVA was implemented in clinical practice. There have been multiple recorded live births and ongoing pregnancies. Further investigations are essential to confirm the efficacy and safety of IVA before used widely in clinics. This review aimed to summarize the published literature on IVA and provide future perspectives for its improvement.
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Robinson, G., J. J. Evans, and M. E. Forster. "Oxytocin can affect follicular development in the adult mouse." Acta Endocrinologica 108, no. 2 (February 1985): 273–76. http://dx.doi.org/10.1530/acta.0.1080273.
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Abstract. Injection of oxytocin into normal adult cycling mice caused alterations in ovarian histology. Oxytocin was administered early on the day of pro-oestrus and it induced the appearance of large numbers of corpora lutea by late pro-oestrus, suggesting oxytocin stimulated ovulation. When mice were examined very early on the day of normal oestrus the ovarian population of follicles was different in the experimental group from that in the control mice, there being increased numbers of preantral and antral follicles in treated animals. As oxytocin can cause an alteration in the timing of follicular maturation and ovulation processes study of communications between the adenohypophysis and areas containing oxytocin might be important for understanding physiological details of ovulation. The relative times at which, for instance, antral follicle and corpora lutea populations increased suggested that oxytocin might have more than one activity which affects ovarian behaviour.
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Chun, S. Y., K. M. Eisenhauer, S. Minami, H. Billig, E. Perlas, and A. J. Hsueh. "Hormonal regulation of apoptosis in early antral follicles: follicle-stimulating hormone as a major survival factor." Endocrinology 137, no. 4 (April 1996): 1447–56. http://dx.doi.org/10.1210/endo.137.4.8625923.
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De los Reyes, M., F. Ramirez, and J. Palomino. "123 EVALUATION OF LUTEINIZING HORMONE RECEPTOR (LHR) OVER THE ESTROUS CYCLE IN CANINE OVARIES." Reproduction, Fertility and Development 29, no. 1 (2017): 170. http://dx.doi.org/10.1071/rdv29n1ab123.
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Luteinizing hormone (LH) plays a major role in reproductive processes. This hormone exerts its effects through binding to its receptor LHR, which is one of the 7 transmembrane domain G-protein-coupled receptor superfamilies. Compared with other mammals, an early acquisition of LH receptors on granulosa cells has been reported in dogs around the period of LH surge, during the proestrous-oestrous transition. However, there are no available data with respect to the follicular stage at which LHR starts to become expressed. Hence, the aim of this study was to determine the LHR pattern in the canine ovarian follicles at different stages of development. The ovaries were obtained from 1- to 7-year-old bitches at proestrus/oestrus, anestrus, and diestrus stages following ovariohysterectomy. Follicular cells were mechanically recovered from follicles (n = 2,043) distributed into 4 types (preantral, small antral, medium antral, and large antral). Intrafollicular amounts of LHR were assessed by Western blot method (with the goat polyclonal anti-LHR antibody SC-26341 at 1:100 dilution) and results were evaluated by a 2-way ANOVA (follicle type, stage of oestrous cycle). The LHR was detected in dog follicles in all reproductive phases with patterns varying with stage of follicular development over the reproductive cycle. The antibody against human LHR, which had previously been proven to cross-react with canine LHR, revealed 2 bands at ~90 and ~65 kDa, probably representing the matured protein and its precursor, respectively. Both bands LHR appeared already at preantral follicles increasing (P < 0.05) with growth. Densitometric analysis of each immunoreactive band showed that LHR level changed among the different development stages and phases of reproductive cycle. These bands appeared to be specific for LH, as the secondary antibody alone did not produce cross-reactivity. During proestrus/oestrus, follicular cells expressed mostly the precursor form, increasing significantly with an increase in follicular diameter. The mature form showed a lower (P < 0.05) intensity band, which increased from the preantral to preovulatory stage. At diestrus, the relative abundance of these bands was different between the precursors and mature forms, with a higher expression of precursor form in all follicle stages and rising (P < 0.05) immunoreactivity from the preantral to medium antral stage. The mature form also exhibited LHR variation among follicle sizes (P < 0.05). At anestrous, both bands were expressed with increasing (P < 0.05) levels from preantral to antral follicle stages. A high proportion of LHR was presented as immature forms in all follicles stages during different phases of the oestrous cycle. In conclusion, the LHR is differentially expressed in dogs over the oestrous cycle, increasing during development, and the precursor protein is the most predominant LHR form present in canine follicles. This study was funded by Grant FONDECYT 1140658.
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Walters, Kirsty A., John P. Binnie, Bruce K. Campbell, David G. Armstrong, and Evelyn E. Telfer. "The effects of IGF-I on bovine follicle development and IGFBP-2 expression are dose and stage dependent." Reproduction 131, no. 3 (March 2006): 515–23. http://dx.doi.org/10.1530/rep.1.00682.
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This study aimed to determine the effect of insulin-like growth factor-I (IGF-I) on early antral bovine follicular development, and the expression of insulin-like growth factor-binding protein-2 (IGFBP-2). Antral follicles separated into three different size groups were cultured for 6 days in medium supplemented with either a low (10 ng/ml) or high (1 μg/ml) dose of human recombinant IGF-I. Oestradiol production by follicles in all size ranges, cultured in the presence of the high concentration of IGF-I, significantly increased by day 6 (P < 0.05). Follicles in the smallest size range, 165–215 μm, cultured in a high dose of IGF-I, were found to be significantly increased in size (P < 0.01). Oocyte health of the largest follicles (281–380 μm) was significantly improved by the addition of IGF-I to the culture medium. mRNA expression of IGFBP-2 was decreased in the granulosa cells of follicles, size range 216–280 μm, cultured with a high dose of IGF-I (P < 0.05). Granulosa cells (P < 0.05) and oocytes (P < 0.01) of the largest follicles (281–380 μm) showed a decrease in IGFBP-2 expression (protein) when cultured in the control and low-IGF-I treatment groups. Therefore, the response of a bovine follicle to IGF-I is both dose and stage dependent. This work supports a role for IGF-I in modulating somatic and germ-cell maturation and development in early antral follicles. Furthermore, the inverse relationship between the level of IGF-I stimulation and IGFBP-2 expression suggests a local regulatory system modulating IGF-I availability.
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Knight, Phil G., and Claire Glister. "TGF-β superfamily members and ovarian follicle development." Reproduction 132, no. 2 (August 2006): 191–206. http://dx.doi.org/10.1530/rep.1.01074.
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In recent years, exciting progress has been made towards unravelling the complex intraovarian control mechanisms that, in concert with systemic signals, coordinate the recruitment, selection and growth of follicles from the primordial stage through to ovulation and corpus luteum formation. A plethora of growth factors, many belonging to the transforming growth factor-β (TGF-β ) superfamily, are expressed by ovarian somatic cells and oocytes in a developmental, stage-related manner and function as intraovarian regulators of folliculogenesis. Two such factors, bone morphogenetic proteins, BMP-4 and BMP-7, are expressed by ovarian stromal cells and/or theca cells and have recently been implicated as positive regulators of the primordial-to-primary follicle transition. In contrast, evidence indicates a negative role for anti-Mullerian hormone (AMH, also known as Mullerian-inhibiting substance) of pre-granulosa/granulosa cell origin in this key event and subsequent progression to the antral stage. Two other TGF-β superfamily members, growth and differentiation factor-9 (GDF-9) and BMP-15 (also known as GDF-9B) are expressed in an oocyte-specific manner from a very early stage and play key roles in promoting follicle growth beyond the primary stage; mice with null mutations in the gdf-9 gene or ewes with inactivating mutations in gdf-9 or bmp-15 genes are infertile with follicle development arrested at the primary stage. Studies on later stages of follicle development indicate positive roles for granulosa cell-derived activin, BMP-2, -5 and -6, theca cell-derived BMP-2, -4 and -7 and oocyte-derived BMP-6 in promoting granulosa cell proliferation, follicle survival and prevention of premature luteinization and/or atresia. Concomitantly, activin, TGF-β and several BMPs may exert paracrine actions on theca cells to attenuate LH-dependent androgen production in small to medium-size antral follicles. Dominant follicle selection in monovular species may depend on differential FSH sensitivity amongst a growing cohort of small antral follicles. Changes in intrafollicular activins, GDF-9, AMH and several BMPs may contribute to this selection process by modulating both FSH- and IGF-dependent signalling pathways in granulosa cells. Activin may also play a positive role in oocyte maturation and acquisition of developmental competence. In addition to its endocrine role to suppress FSH secretion, increased output of inhibin by the selected dominant follicle(s) may upregulate LH-induced androgen secretion that is required to sustain a high level of oestradiol secretion during the pre-ovulatory phase. Advances in our understanding of intraovarian regulatory mechanisms should facilitate the development of new approaches for monitoring and manipulating ovarian function and improving fertility in domesticated livestock, endangered species and man.
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Pöhland, R., S. Lenz, J. Vanselow, and W. Tomek. "Detection of gene expression and enzyme activity of Cytochrom P450 arom (aromatase) in preantral and early antral bovine follicles depending on culture conditions in vitro." Archives Animal Breeding 49, no. 1 (October 10, 2006): 29–40. http://dx.doi.org/10.5194/aab-49-29-2006.
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Abstract. This study reveals that cultivation of preantral and early antral (< 500 μm) follicles in culture medium containing FCS results in an expression of cytochrome P450 arom. (aromatase). The enzymatic activity of aromatase, measured in terms of the estradiol synthesis, was proved to be present in follicles greater than 100 μm, could further be stimulated by FSH in follicles greater than 300 μm diameter. The enzyme protein and the gene expression were studied by means of western blot and immunohistochemistry as well as by means of realtime PCR. Neither the protein nor the corresponding mRNA could be found in uncultivated follicles and in FCS-free cultivated follicles. Estradiol synthesis could not be determined under FCS-free conditions. The expression of the FCS effect was dependent on the follicle size.
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McMahon, Heather E., Osamu Hashimoto, Pamela L. Mellon, and Shunichi Shimasaki. "Oocyte-Specific Overexpression of Mouse Bone Morphogenetic Protein-15 Leads to Accelerated Folliculogenesis and an Early Onset of Acyclicity in Transgenic Mice." Endocrinology 149, no. 6 (February 28, 2008): 2807–15. http://dx.doi.org/10.1210/en.2007-1550.
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Whereas mutations in the bmp15 gene cause infertility in ewes and women due to defects in folliculogenesis, most defects in female mice lacking bone morphogenetic protein (BMP)-15 are confined to the ovulation process, supportive of the observation that functional mouse BMP-15 is barely detected in oocytes in vivo until after the LH surge. In addition, the mouse BMP-15 proprotein is not processed into the functional mature protein in transfected cells. However, a chimeric protein consisting of the human proregion, human cleavage site, and mouse mature region (termed hhmBMP-15) is processed and the mature protein secreted. To study the role of BMP-15 in folliculogenesis, we generated transgenic mice overexpressing hhmBMP-15, exclusively in oocytes during folliculogenesis and confirmed the overexpression of mouse BMP-15 mature protein. Immature transgenic mice exhibited accelerated follicle growth with decreased primary follicles and an increase in secondary follicles. Granulosa cells of immature mice displayed an increased mitotic index and decreased FSH receptor mRNA expression. Adult mice had normal litter sizes but an increased number of atretic antral follicles. Interestingly, aging mice exhibited an early onset of acyclicity marked by increased diestrus length and early occurrence of constant diestrus. These findings indicate the role of BMP-15 in vivo in promoting follicle growth and preventing follicle maturation, resulting in an early decline in the ovarian reserve of transgenic mice. Therefore, the lack of mouse BMP-15 during early folliculogenesis in the wild-type mice may be relevant to their polyovulatory nature as well as the preservation of ovarian function as the mice age.
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Jazwiec, Patrycja A., Xinglin Li, Brad Matushewski, Bryan S. Richardson, and Deborah M. Sloboda. "Fetal Growth Restriction Is Associated With Decreased Number of Ovarian Follicles and Impaired Follicle Growth in Young Adult Guinea Pig Offspring." Reproductive Sciences 26, no. 12 (February 11, 2019): 1557–67. http://dx.doi.org/10.1177/1933719119828041.
Full textAbstract:
Background: The mechanisms mediating the impacts of fetal growth restriction (FGR) on follicular development are commonly studied in mouse/rat models, where ovarian development occurs largely during the early postnatal period. These models have shown that FGR is associated with premature follicle loss, early pubertal onset, and accelerated ovarian aging. Whether the same occurs in precocious species is unknown. Objective: Since guinea pig follicle development occurs in utero in a manner consistent with human ovarian development, we sought to determine whether FGR had similar impacts on guinea pig ovarian development. Methods: Dunkin-Hartley guinea pig dams were randomized to receive a control (CON) or a nutrient-restricted diet (FGR) prior to conception until weaning. Offspring ovaries were collected at prepubertal (postnatal day [P] 25) and young adult (P110) time points. Results: Prepubertal offspring exposed to FGR showed little differences in ovarian transcript levels and follicle counts. Young adult FGR offspring, however, showed reductions in the number of transitioning, primary, and antral follicles, as well as corpora lutea. This loss in follicles was associated with reduced insulin-like growth factor receptor and growth differentiation factor-9 messenger RNA levels in FGR P110 offspring compared to CON. Conclusion: We demonstrate that FGR in guinea pigs is accompanied by perturbations in signaling pathways essential for proper follicle growth and manifests as reductions in growing follicles in offspring, but these changes do not manifest until postpuberty. These data support the fact that accelerated reproductive maturation/aging is a conserved phenotype that is associated with in utero nutritional adversity.
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Cossigny, Davina A., Jock K. Findlay, and Ann E. Drummond. "The effects of FSH and activin A on follicle development in vitro." REPRODUCTION 143, no. 2 (February 2012): 221–29. http://dx.doi.org/10.1530/rep-11-0105.
Full textAbstract:
Numerous studies have reported on the roles of activins in gonadal regulation; however, little is known about their specific roles in early folliculogenesis. Ovarian follicular growth was investigated in 10-day cultures of day 4 postnatal whole ovaries treated with activin A (ActA; 50 ng/ml), with or without FSH (100 ng/ml) in vitro. We hypothesized that treatment with ActA±FSH would affect rates of growth and atresia in follicles. None of the treatments affected primordial follicle activation, and antral follicles were not observed after 10 days in culture. Primordial follicle numbers from all treatment groups were ∼20% of those in day 4 fresh ovaries, indicating that activation had occurred. In the presence of ActA, preantral follicle numbers increased significantly (P<0.0001). ActA alone decreased the proportion of atretic follicles in the primary and preantral classes, whereas the combined treatment of ActA+FSH increased the proportion of atretic preantral oocytes. Real-time PCR analysis revealed that follistatin, FSH receptor, and activin βA and βB subunits were all expressed at significantly higher levels in the ActA-only treated group but not in the ActA+FSH group. Here, we report novel findings supporting the role of FSH in primordial follicle survival through an action on apoptosis and a stimulatory role of ActA in the primordial to primary and preantral stages of follicle development, suggesting an inhibitory action of activin on oocyte apoptosis.