Changes in concentrations of follicular fluid factors during follicle selection in mares.
Abstract: The temporal relationships in the changes in concentrations of follicular fluid factors during follicle selection were characterized in mares. All follicles > or =5 mm were ablated 10 days after ovulation, followed by follicular fluid collection from the three largest follicles (F1, F2, and F3) when F1 of the new wave reached a diameter of 8.0-11.9, 12.0-15.9, 16.0-19.9, 20.0-23.9, 24.0-27.9, or 28.0-31.9 mm (n = 4-8 mares/range). Diameter deviation between F1 and F2 began during the 20.0- to 23.9-mm range, as indicated by a greater difference in diameter between the two follicles at the 24.0- to 27.9-mm range than at the 20.0- to 23.9-mm range. Androstenedione concentrations increased in F1, F2, and F3 between the 16.0- to 19.9- and 20.0- to 23.9-mm ranges. In contrast, estradiol, free insulin-like growth factor (IGF)-1, activin-A, and inhibin-A concentrations increased only in F1 beginning at the 16.0- to 19.9-mm range. As a result, the concentrations of all four factors were higher in F1 than in F2 and F3 at all the later ranges, including the 20.0- to 23.9-mm range (beginning of diameter deviation). Concentrations of progesterone differentially increased in F1, concentrations of androstenedione and IGF-binding protein (IGFBP)-2 increased only in F2 and F3, and concentrations of inhibin-B differentially decreased in F2 and F3 simultaneous with the beginning of deviation. Concentrations of FSH, LH, pro-alphaC inhibin, and total inhibin did not change differentially among follicles. Results indicated that, on a temporal basis, estradiol, free IGF-1, activin-A, and inhibin-A may have played a role in the initiation of follicle deviation. In addition, these four factors as well as progesterone, androstenedione, IGFBP-2, and inhibin-B may have been involved in the subsequent differential development of the follicles.
Publication Date: 2002-03-22 PubMed ID: 11906932DOI: 10.1095/biolreprod66.4.1111Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research investigates the timing and changes in key hormone concentrations present in the follicular fluid of mares during follicle selection. It suggests certain hormones may play a pivotal role in initiating follicle deviation and subsequent development of follicles.
Objective and Methodology
- The study aimed to understand the dynamics of alterations in the concentration of numerous factors in the follicular fluid during the process of follicle selection in mares.
- All follicles greater than or equal to 5 mm were removed 10 days following ovulation. The three largest follicles (F1, F2, and F3) were then selected for collecting follicular fluid.
- Fluid collection was done at different intervals, based on the diameter of the primary follicle (F1) including different diameter ranges from 8.0-11.9 mm to 28.0-31.9 mm.
Follicle Diameter Deviation and Hormonal Changes
- The diameter difference between the first and second largest follicles started increasing in the 20.0-23.9 mm diameter range, indicating initiation of the follicle selection or deviation process.
- Concentration of androstenedione, a steroid hormone, increased in all three follicles studied (F1, F2, and F3) between the 16 and 24 mm diameter ranges of F1.
- In contrary, the levels of estradiol, free insulin-like growth factor (IGF-1), activin-A, and inhibin-A increased only in the primary follicle (F1) at the 16.0-19.9 mm range. As a result, these four factors were more concentrated in F1 than in F2 & F3 across all subsequent ranges.
Changes in Hormone Concentrations During Follicle Deviation
- Progesterone levels increased differentially in F1, concentrations of androstenedione and IGF-binding protein -2 increased only in F2 and F3, while levels of inhibin-B decreased in F2 and F3 coinciding with the start of follicle deviation.
- Concentrations of follicle stimulating hormone (FSH), luteinizing hormone (LH), pro-alphaC inhibin, and total inhibin did not differ significantly among follicles.
Implications of the Study
- The study suggests that hormones like estradiol, free IGF-1, activin-A, and inhibin-A could play a significant role in the commencement of follicle deviation.
- These hormones, along with others like progesterone, androstenedione, IGFBP-2, and inhibin-B, may participate in the differential growth and development of the follicles post deviation.
Cite This Article
APA
Donadeu FX, Ginther OJ.
(2002).
Changes in concentrations of follicular fluid factors during follicle selection in mares.
Biol Reprod, 66(4), 1111-1118.
https://doi.org/10.1095/biolreprod66.4.1111 Publication
Researcher Affiliations
- Department of Animal Health and Biomedical Sciences, University of Wisconsin, 1656 Linden Drive, Madison, WI 53706, USA. donadeu@ahabs.wisc.edu
MeSH Terms
- Activins / analysis
- Androstenedione / analysis
- Animals
- Estradiol / analysis
- Female
- Follicular Fluid / chemistry
- Horses / physiology
- Inhibin-beta Subunits / analysis
- Inhibins / analysis
- Insulin-Like Growth Factor Binding Protein 2 / analysis
- Insulin-Like Growth Factor I / analysis
- Ovarian Follicle / anatomy & histology
- Ovarian Follicle / physiology
- Ovulation
- Progesterone / analysis
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).
- Li L, Deng X, Hu S, Cui Z, Ning Z, Gui T, Zhao X, Li D, Wang Y, Yin H, Ye L, Tian Y, Zhang Y, Li H, Zhu Q. Systematic Analysis of Long Noncoding RNA and mRNA in Granulosa Cells during the Hen Ovulatory Cycle. Animals (Basel) 2021 May 25;11(6).
- 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).
- Ginther OJ, Beg MA, Gastal EL, Gastal MO, Baerwald AR, Pierson RA. Systemic concentrations of hormones during the development of follicular waves in mares and women: a comparative study. Reproduction 2005 Sep;130(3):379-88.
- Medan MS, Nambo Y, Nagamine N, Shinbo H, Watanabe G, Groome N, Taya K. Plasma concentrations of ir-inhibin, inhibin A, inhibin pro-alphaC, FSH, and estradiol-17beta during estrous cycle in mares and their relationship with follicular growth. Endocrine 2004 Oct;25(1):7-14.
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