Alterations in follicular IGFBP mRNA expression and follicular fluid IGFBP concentrations during the first follicle wave in beef heifers

Canty, Mary J.; Boland, M.P.; Evans, A.C.O.; Crowe, M.A.

doi:10.1016/j.anireprosci.2005.06.033

Cited by 34 publications

(22 citation statements)

References 52 publications

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“…Follicle selection occurs in the face of declining FSH concentrations and is the process by which the growing cohort of follicles is reduced to the ovulatory quota for the species (in cattle it is generally one; Sunderland et al, 1994). The selected follicle survives in an environment of reduced FSH owing to the development of LH receptors in the granulosa cells (Xu et al, 1995;Bao et al 1997) and increased intrafollicular bioavailable IGF-I (Austin et al, 2001;Canty et al, 2006). The increased bioavailable IGF-I is achieved by reduced IGF-I-binding proteins (IGFBP) because of increased IGFBP protease activity.…”

Section: Introductionmentioning

confidence: 99%

“…The concurrent LH pulse frequency determines the fate of the first follicular wave-dominant follicle that is dependent on its ability to secrete sufficient oestradiol to induce a gonadotrophin surge. The capacity for oestradiol secretion is in turn dependent on the prevailing LH pulse frequency during the dominant phase of the follicle wave, the size of the dominant follicle and IGF-I bioavailability (Austin et al, 2001;Canty et al, 2006). Therefore, the major driver for ovulation of a dominant follicle during the postpartum period is the GnRH/LH pulse frequency.…”

Section: Introductionmentioning

confidence: 99%

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Parturition to resumption of ovarian cyclicity: comparative aspects of beef and dairy cows

Crowe

Diskin

Williams

2014

Animal

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100

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There is a variable anoestrous period following parturition in the cow. Follicular growth generally resumes within 7 to 10 days in the majority of cows associated with a transient FSH rise that occurs within 3 to 5 days of parturition. Dairy cows that are not nutritionally stressed generally ovulate their first postpartum dominant follicle (~15 days), whereas beef suckler cows in good body condition normally have a mean of 3.2 ± 0.2 dominant follicles (~30 days) to first ovulation; moreover, beef cows in poor body condition have a mean of 10.6 ± 1.2 dominant follicles (~70 to 100 days) to first ovulation. The lack of ovulation of dominant follicles during the postpartum period is associated with infrequent LH pulses, with both maternal-offspring bonding and low body condition score (BCS) at calving being implicated as the predominant causes of delayed resumption of cyclicity in nursed beef cows. In dairy cows, the normal pattern of early resumption of ovulation may be delayed in high-yielding Holstein type cows generally owing to the effects of severe negative energy balance, dystocia, retained placental membranes and uterine infections. First ovulation, in both dairy and beef cows, is generally silent (i.e., no behavioural oestrus) and followed by a short inter-ovulatory interval (>70%). The key to optimizing the resumption of ovulation in both beef and dairy cows is appropriate pre-calving nutrition and management so that cows calve down in optimal body condition (BCS; 2.75 to 3.0) with postpartum body condition loss restricted to < 0.5 BCS units.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Parturition to resumption of ovarian cyclicity: comparative aspects of beef and dairy cows

Crowe

Diskin

Williams

2014

Animal

Self Cite

100

View full text Add to dashboard Cite

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“…Previous studies have used the bovine DF model to examine changes in the expression of known follicular genes (such as for FSH and LH receptors, steroidogenic enzymes, specific growth factors and their binding proteins) when the DF becomes selected from the cohort , Yuan et al 1998, Canty et al 2006. While this candidate gene approach has merit, it is clear that approaches that utilise global gene and protein expression profiling are required to identify all key factors and pathways which regulate cell differentiation during DF development.…”

Section: Introductionmentioning

confidence: 99%

Differentiation of the bovine dominant follicle from the cohort upregulates mRNA expression for new tissue development genes

Mihm¹,

Baker²,

Fleming³

et al. 2008

Reproduction

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This study was designed to identify genes that regulate the transition from FSH-to LH-dependent development in the bovine dominant follicle (DF). Serial analysis of gene expression (SAGE) was used to compare the transcriptome of granulosa cells isolated from the most oestrogenic growing cohort follicle (COH), the newly selected DF and its largest subordinate follicle (SF) which is destined for atresia. Follicle diameter, follicular fluid oestradiol (E) and E:progesterone ratio confirmed follicle identity. Results show that there are 93 transcript species differentially expressed in DF granulosa cells, but only 8 of these encode proteins known to be involved in DF development. Most characterised transcripts upregulated in the DF are from tissue development genes that regulate cell differentiation, proliferation, apoptosis, signalling and tissue remodelling. Semiquantitative real-time PCR analysis confirmed seven genes with upregulated (P%0.05) mRNA expression in DF compared with both COH and SF granulosa cells. Thus, the new genes identified by SAGE and real-time PCR, which show enhanced mRNA expression in the DF, may regulate proliferation (cyclin D2; CCND2), prevention of apoptosis or DNA damage (growth arrest and DNA damage-inducible, b; GADD45B), RNA synthesis (splicing factor, arginine/serine rich 9; SFRS9) and unknown processes associated with enhanced steroidogenesis (ovary-specific acidic protein; DQ004742) in granulosa cells of DF at the onset of LH-dependent development. Further studies are required to show whether the expression of identified genes is dysregulated when abnormalities occur during DF selection or subsequent development.

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“…However, it can be hypothesized that the follicle destined to become dominant maintains an ability to grow in the presence of declining FSH concentrations due to a number of possible mechanisms: i) increased bioavailability of insulin-like growth factor-I (IGF-I) in that follicle due to reduced total IGF-I binding protein activity (Mihm et al, 1997;Stewart et al, 1996;Canty et al, 2006); ii) expression of LH-receptor messenger RNA (Bao et al, 1997) and LH-receptors (Ireland and Roche, 1983) in granulosa cells of that follicle rendering it more responsive to LH than other follicles in the cohort. Further use of the models discussed in this paper along with identification of expression of key genes involved with these processes should provide further insights in the near future.…”

Section: Discussionmentioning

confidence: 99%

Relative Roles of FSH and LH in Stimulation of Effective Follicular Responses in Cattle

Crowe¹,

Mullen²

2013

Gonadotropin

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Alterations in follicular IGFBP mRNA expression and follicular fluid IGFBP concentrations during the first follicle wave in beef heifers

Cited by 34 publications

References 52 publications

Parturition to resumption of ovarian cyclicity: comparative aspects of beef and dairy cows

Parturition to resumption of ovarian cyclicity: comparative aspects of beef and dairy cows

Differentiation of the bovine dominant follicle from the cohort upregulates mRNA expression for new tissue development genes

Relative Roles of FSH and LH in Stimulation of Effective Follicular Responses in Cattle

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