Follicular development: the role of the follicular microenvironment in selection of the dominant follicle

Fortune, J.E.; Rivera, Gonzalo; Yang, Ming

doi:10.1016/j.anireprosci.2004.04.031

Cited by 226 publications

(207 citation statements)

References 44 publications

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“…In addition, proteolysis of IGFBP-4 and -5 in follicular fluid has been shown to have implications for follicular selection and dominance in cattle (Rivera & Fortune 2003). The importance of the IGF system in determining follicular fate in dominant follicles and stage-specific effects have been studied extensively (refer to Fortune et al 2004). A cell-specific pattern of components of the IGF system and gonadotropin receptor gene expression has also been demonstrated in bovine cumulus-oocyte complexes during oocyte maturation (Nuttinck et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Thomas¹,

Campbell²,

Armstrong³

et al. 2007

Reproduction

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The aim of this study was to determine the effect of regulation of IGF-I bioavailability on preantral follicle development in vitro. Bovine preantral follicles were cultured for 6 days in serum-free medium with increasing doses of Long R3 (LR3) IGF-I (an analog with low affinity for IGF-binding proteins (IGFBPs)), or human recombinant IGF-I (hrIGF-I). Follicle diameter and estradiol production were measured every second day. On day 6, ratios of oocyte/follicle diameter and oocyte morphology were assessed by histological examination, and IGFBP-2 and -3 were detected by immunocytochemistry and in situ hybridization respectively. Both types of IGF-I increased follicle diameter in a dose-dependent manner (P!0.05) and increased estradiol production over control levels (P!0.05). However, follicles treated with LR3 IGF-I and the highest concentration of hrIGF-I (1000 ng/ml) had smaller oocyte/follicle ratios, and increased oocyte degeneration, compared with controls or follicles treated with physiological concentrations of hrIGF-I (P!0.05). IGFBPs were detected in cultured preantral follicles, indicating a requirement for regulation of IGF bioavailability during the early stages of follicular development. Specifically, IGFBP-3 mRNA was found to be expressed in oocytes, and IGFBP-2 immunoreactivity was detected in oocytes and granulosa cells of cultured follicles. In summary, the regulation of IGF-I bioavailability by IGFBPs is necessary for the co-ordination of oocyte and follicle development in vitro.

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Section: Introductionmentioning

confidence: 99%

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Thomas¹,

Campbell²,

Armstrong³

et al. 2007

Reproduction

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“…Gonadotropins (both luteinizing hormone (LH) and follicle-stimulating hormone (FSH)) play a central role in the processes. Growth factors may act directly to control follicular growth or may act indirectly by modifying the sensitivity of follicular cells to FSH and LH (Lucy 2000, Richards et al 2002a,b, Webb et al 2003, Fortune et al 2004. The release of the LH surge near the onset of estrus redirects preovulatory development and causes the biochemical differentiation of the follicle (luteinization) and ovulation (Richards et al 2002, Murdoch & Gottsch 2003.…”

Section: Introductionmentioning

confidence: 99%

Luteinization of porcine preovulatory follicles leads to systematic changes in follicular gene expression

Ağca

Ries²,

Kolath³

et al. 2006

Reproduction

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The LH surge initiates the luteinization of preovulatory follicles and causes hormonal and structural changes that ultimately lead to ovulation and the formation of corpora lutea. The objective of the study was to examine gene expression in ovarian follicles (nZ11) collected from pigs (Sus scrofa domestica) approaching estrus (estrogenic preovulatory follicle; nZ6 follicles from two sows) and in ovarian follicles collected from pigs on the second day of estrus (preovulatory follicles that were luteinized but had not ovulated; nZ5 follicles from two sows). The follicular status within each follicle was confirmed by follicular fluid analyses of estradiol and progesterone ratios. Microarrays were made from expressed sequence tags that were isolated from cDNA libraries of porcine ovary. Gene expression was measured by hybridization of fluorescently labeled cDNA (preovulatory estrogenic or -luteinized) to the microarray. Microarray analyses detected 107 and 43 genes whose expression was decreased or increased (respectively) during the transition from preovulatory estrogenic to -luteinized (P!0.01). Cells within preovulatory estrogenic follicles had a gene-expression profile of proliferative and metabolically active cells that were responding to oxidative stress. Cells within preovulatory luteinized follicles had a gene-expression profile of nonproliferative and migratory cells with angiogenic properties. Approximately, 40% of the discovered genes had unknown function.

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“…Insulin-like growth factor (IGF)-1 mediates the transition from gonadotropin responsiveness to dependency via enhancement of gonadotropin receptor expression and stimulation of steroidogenesis (Silva et al 2009;Scaramuzzi et al 2011). Dominant follicles gain ovulatory potential by transition from FSH to LH dependency accompanied by an increase in 17β-oestradiol (E2) in the follicular fluid (Campbell et al 1999;Fortune et al 2004;Hunter et al 2004;Baerwald et al 2012). …”

Section: Introductionmentioning

confidence: 99%

Localisation and endocrine control of hyaluronan synthase (HAS) 2, HAS3 and CD44 expression in sheep granulosa cells

Chavoshinejad

Marei

Hartshorne

et al. 2016

Reprod. Fertil. Dev.

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The aim of the present study was to investigate the hormonal regulation of hyaluronan (HA) components in sheep granulosa cells. HA components are present in the reproductive tract and have a range of physical and signalling properties related to reproductive function in several species. First, abattoir-derived ovaries of sheep were used to determine the localisation of HA synthase (HAS) 1–3 and CD44 proteins in antral follicles. Staining for HAS1–3 and CD44 proteins was most intense in the granulosa layer. Accordingly, the expression of HAS2, HAS3 and CD44 mRNA was measured in cultured granulosa cells exposed to 0–50 ng mL–1 of 17β-oestradiol and different combinations of oestradiol, gonadotropins, insulin-like growth factor (IGF)-1 and insulin for 48–96 h (1 ng mL–1 FSH, 10 ng mL–1 insulin, 10 ng mL–1 IGF-1, 40 ng mL–1 E2 and 25 ng mL–1 LH.). mRNA expression was quantified by real-time polymerase chain reaction using a fold induction method. The results revealed that the hormones tested generally stimulated mRNA expression of the genes of interest in cultured granulosa cells. Specifically, oestradiol, when combined with IGF-1, insulin and FSH, stimulated HAS2 mRNA expression. Oestradiol and LH had synergistic effects in increasing HAS3 mRNA expression. In conclusion, we suggest that the hormones studied differentially regulate HAS2, HAS3 and CD44 in ovine granulosa cells in vitro. Further work is needed to address the signalling pathways involved.

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Follicular development: the role of the follicular microenvironment in selection of the dominant follicle

Cited by 226 publications

References 44 publications

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Effects of IGF-I bioavailability on bovine preantral follicular development in vitro

Luteinization of porcine preovulatory follicles leads to systematic changes in follicular gene expression

Localisation and endocrine control of hyaluronan synthase (HAS) 2, HAS3 and CD44 expression in sheep granulosa cells

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