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Changes in intrafollicular concentrations of free IGF-1, activin A, inhibin A, VEGF, estradiol, and prolactin before ovulation in mares.
Abstract: Changes in intrafollicular growth factors and hormones were evaluated in vivo in postdeviation and impending ovulation follicles. Mares (n = 30) were randomly assigned to five experimental groups based on target diameters of 25, 30, 35, 40 mm, and impending signs of ovulation. Furthermore, data belonging to two or more proximal diameter groups that were not different were combined and regrouped for each factor separately. Follicular fluid-free insulin-like growth factor 1 was highest (P 0.05) among groups. Additionally, follicular fluid activin A tended (P < 0.06) to be higher in impending ovulation follicles when compared with the 25- to 40-mm follicle group. Concentrations of intrafollicular estradiol were higher (P < 0.0001) in 40-mm and impending ovulation follicles than in the other follicle groups. Follicular fluid concentrations of inhibin A and vascular endothelial growth factor were lower (P < 0.05) in the 40-mm and the impending ovulation follicle group when compared with the 25- to 35-mm follicle group. Systemic and intrafollicular prolactin levels were lower (P < 0.05) in the impending ovulation group when compared with the 25- to 40-mm follicle group. Prolactin concentrations were higher (P < 0.05) in the follicular fluid than in the plasma. The novel findings of this study, a decrease in intrafollicular-free insulin-like growth factor 1, inhibin A, vascular endothelial growth factor, and prolactin during the final stages of follicular growth, document for the first time the occurrence of dynamic changes among intrafollicular factors and hormones during the stages of follicle dominance and as ovulation approaches.
Copyright © 2016 Elsevier Inc. All rights reserved.
Publication Date: 2016-01-18 PubMed ID: 26895618DOI: 10.1016/j.theriogenology.2016.01.013Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
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The research investigates the changes in intrafollicular concentrations of specific growth factors and hormones in mares during ovulation, identifying that levels of free insulin-like growth factor 1 (IGF-1), inhibin A, vascular endothelial growth factor (VEGF), and prolactin decreased during the latter stages of follicular growth.
Objective and Methodology
The objective of this study was to evaluate changes in intrafollicular concentrations of certain growth factors and hormones in mares at different stages of follicle dominance up to ovulation.
- Thirty mares were randomly divided into five groups based on the target diameters of the follicles (25, 30, 35, 40 mm) and impending signs of ovulation.
- Data was grouped according to similarities across diameter groups for each measured factor.
Key Findings
The study found notable differences between the intrafollicular concentrations of specific growth factors and hormones:
- The concentration of follicular fluid-free IGF-1 was highest in 35-mm follicles, followed by the 40-mm and impending ovulation follicle group, and finally, the 25- to 30-mm follicle group.
- Activin A concentrations tended to be higher in follicles about to ovulate when compared to the 25- to 40-mm follicle group.
- The levels of intrafollicular estradiol were significantly higher in 40-mm and impending ovulation follicles than in other follicle groups.
- The study noted lower levels of inhibin A and VEGF in the 40-mm and the impending ovulation follicle group when compared with the 25- to 35-mm follicle group.
- Prolactin levels were also seen to be lower in the follicles about to ovulate, both systemically and intrafollicularly, indicating a decrease during the final stages of follicular growth.
Implication of the Study
This research documents, for the first time, the dynamic changes among intrafollicular factors and hormones during the stages of follicle dominance and near ovulation. This could provide significant insights into the biological process related to ovulation and fertility and could have implications for reproductive management and treatment.
Cite This Article
APA
Bashir ST, Ishak GM, Gastal MO, Roser JF, Gastal EL.
(2016).
Changes in intrafollicular concentrations of free IGF-1, activin A, inhibin A, VEGF, estradiol, and prolactin before ovulation in mares.
Theriogenology, 85(8), 1491-1498.
https://doi.org/10.1016/j.theriogenology.2016.01.013 Publication
Researcher Affiliations
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, Illinois, USA.
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, Illinois, USA.
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, Illinois, USA.
- Department of Animal Science, University of California, Davis, California, USA.
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, Illinois, USA. Electronic address: egastal@siu.edu.
MeSH Terms
- Activins / metabolism
- Animals
- Estradiol / metabolism
- Female
- Follicular Fluid / metabolism
- Horses / metabolism
- Inhibins / metabolism
- Insulin-Like Growth Factor I / metabolism
- Intercellular Signaling Peptides and Proteins / metabolism
- Ovarian Follicle / growth & development
- Ovarian Follicle / metabolism
- Ovulation / metabolism
- Prolactin / metabolism
- Random Allocation
- Vascular Endothelial Growth Factor A / metabolism
Citations
This article has been cited 5 times.- Gebremedhn S, Gad A, Ishak GM, Menjivar NG, Gastal MO, Feugang JM, Prochazka R, Tesfaye D, Gastal EL. Dynamics of extracellular vesicle-coupled microRNAs in equine follicular fluid associated with follicle selection and ovulation. Mol Hum Reprod 2023 Apr 3;29(4).
- Satué K, Fazio E, Medica P. Can the Presence of Ovarian Corpus Luteum Modify the Hormonal Composition of Follicular Fluid in Mares?. Animals (Basel) 2020 Apr 9;10(4).
- Montani DA, Braga DPAF, Borges E Jr, Camargo M, Cordeiro FB, Pilau EJ, Gozzo FC, Fraietta R, Lo Turco EG. Understanding mechanisms of oocyte development by follicular fluid lipidomics. J Assist Reprod Genet 2019 May;36(5):1003-1011.
- Ishak GM, Bashir ST, Dutra GA, Gastal GDA, Gastal MO, Cavinder CA, Feugang JM, Gastal EL. In vivo antral follicle wall biopsy: a new research technique to study ovarian function at the cellular and molecular levels. Reprod Biol Endocrinol 2018 Jul 28;16(1):71.
- Shim SH, Kim JO, Jeon YJ, An HJ, Lee HA, Kim JH, Ahn EH, Lee WS, Kim NK. Association between vascular endothelial growth factor promoter polymorphisms and the risk of recurrent implantation failure. Exp Ther Med 2018 Feb;15(2):2109-2119.
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