Stimulation of LH, FSH, and luteal blood flow by GnRH during the luteal phase in mares.
Abstract: A study was performed on the effect of a single dose per mare of 0 (n = 9), 100 (n = 8), or 300 (n = 9) of GnRH on Day 10 (Day 0 = ovulation) on concentrations of LH, FSH, and progesterone (P4) and blood flow to the CL ovary. Hormone concentration and blood flow measurements were performed at hours 0 (hour of treatment), 0.25, 0.5, 1, 2, 3, 4, and 6. Blood flow was assessed by spectral Doppler ultrasonography for resistance to blood flow in an ovarian artery before entry into the CL ovary. The percentage of the CL with color Doppler signals of blood flow was estimated from videotapes of real-time color Doppler imaging by an operator who was unaware of mare identity, hour, or treatment dose. Concentrations of LH and FSH increased (P < 0.05) at hour 0.25 and decreased (P < 0.05) over hours 1 to 6; P4 concentration was not altered by treatment. Blood flow resistance decreased between hours 0 and 1, but the decrease was greater (P < 0.05) for the 100-μg dose than for the 300-μg dose. The percentage of CL with blood flow signals increased (P < 0.05) between hours 0 and 1 with no significant difference between the 100- and 300-μg doses. The results supported the hypothesis that GnRH increases LH concentration, vascular perfusion of the CL ovary, and CL blood flow during the luteal phase; however, P4 concentration was not affected.
Copyright © 2016 Elsevier Inc. All rights reserved.
Publication Date: 2015-10-19 PubMed ID: 26600292DOI: 10.1016/j.theriogenology.2015.10.019Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article investigates the effect of the hormone GnRH on the concentrations of LH, FSH, and progesterone, as well as blood flow to the CL ovary in mares during the luteal phase of their reproductive cycle.
Introduction and Methodology
This study was designed to explore the impact of varying doses of GnRH (Gonadotropin-releasing hormone) on certain hormone levels and blood flow in mares. GnRH is a hormone that triggers the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which regulate the reproductive cycle. The timing of this investigation was set to occur on Day 10 of the reproductive cycle, where Day 0 was the ovulation day.
- The study groups consisted of a control group receiving no GnRH (n=9), a group receiving 100 μg of GnRH (n=8), and another receiving 300 μg of GnRH (n=9).
- Hormonal concentrations of LH, FSH, and progesterone (P4), and blood flow to the CL (Corpus Luteum) ovary were measured at multiple intervals post-treatment: 0 hour (at the time of treatment), 0.25, 0.5, 1, 2, 3, 4, and 6 hours.
- Blood flow was measured using spectral Doppler ultrasonography to assess resistance to blood flow in an ovarian artery before entry into the CL ovary.
- An operator, who was uninformed about the mare identity, hour, or treatment dose, estimated the percentage of the CL with color Doppler signals of blood flow from videotapes of real-time color Doppler imaging.
Results and Findings
- The study found that concentrations of LH and FSH increased significantly at hour 0.25, and subsequently decreased over hours 1 to 6; however, the P4 concentration was not changed due to the treatment.
- The resistance to blood flow decreased between hours 0 and 1, with a greater decrease observed for the 100-μg dose than the 300-μg dose.
- The percentage of CL with blood flow signals increased significantly between hours 0 and 1 without any significant difference between the 100- and 300-μg doses.
Conclusion
The results support the hypothesis that GnRH increases LH concentration and vascular perfusion of the CL ovary, and enhances CL blood flow during the luteal phase; nevertheless, P4 concentration remained unaffected. This implies GnRH has a role in regulating blood flow and certain hormone concentrations during the luteal phase of the reproductive cycle in mares.
Cite This Article
APA
Castro T, Oliveira FA, Siddiqui MA, Baldrighi JM, Wolf CA, Ginther OJ.
(2015).
Stimulation of LH, FSH, and luteal blood flow by GnRH during the luteal phase in mares.
Theriogenology, 85(4), 740-746.
https://doi.org/10.1016/j.theriogenology.2015.10.019 Publication
Researcher Affiliations
- Eutheria Foundation, Cross Plains, Wisconsin, USA; Centro de Ciências Agrárias, Universidade Federal do Espírito Santo, Alegre, Espírito Santo, Brazil; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.
- Centro de Ciências Agrárias, Universidade Federal do Espírito Santo, Alegre, Espírito Santo, Brazil.
- Eutheria Foundation, Cross Plains, Wisconsin, USA; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.
- Eutheria Foundation, Cross Plains, Wisconsin, USA; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.
- Eutheria Foundation, Cross Plains, Wisconsin, USA; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.
- Eutheria Foundation, Cross Plains, Wisconsin, USA; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA. Electronic address: ginther@vetmed.wisc.edu.
MeSH Terms
- Animals
- Corpus Luteum / blood supply
- Corpus Luteum / drug effects
- Female
- Follicle Stimulating Hormone / metabolism
- Gonadotropin-Releasing Hormone / administration & dosage
- Gonadotropin-Releasing Hormone / pharmacology
- Horses / physiology
- Luteal Phase / drug effects
- Luteal Phase / physiology
- Luteinizing Hormone / metabolism
Citations
This article has been cited 2 times.- Requena F, Campos MJAPM, Martínez Marín AL, Camacho R, Giráldez-Pérez RM, Agüera EI. Assessment of Age Effects on Ovarian Hemodynamics Using Doppler Ultrasound and Progesterone Concentrations in Cycling Spanish Purebred Mares.. Animals (Basel) 2021 Aug 8;11(8).
- Samir H, Kandiel MMM, El-Maaty AMA, Sediqyar M, Sasaki K, Watanabe G. Ovarian follicular changes and hemodynamics in Egyptian buffaloes under CIDR-PGF2α and Ovsynch-CIDR estrus synchronization treatments.. J Reprod Dev 2019 Oct 23;65(5):451-457.
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