Effect of GnRH and hCG on progesterone concentration and ovarian and luteal blood flow in diestrous mares.
Abstract: The objective of the present study was to investigate the effect of reproductive hormones (GnRH, hCG, LH and progesterone) on the regulation of corpus luteum (CL) and ovarian blood flow. Diestrous mares received a single treatment of saline, 100μg gonadorelin (GnRH), or 1500IU hCG 10days after ovulation. Plasma LH and progesterone concentrations, resistance index (RI) for ovarian artery blood-flow, and percentage of corpus luteum (CL) with color-Doppler signals of blood flow were determined immediately before treatment (hour 0) and at hours 0.25, 0.5, 1, 1.5, 2, 3, 4, 5, and 6. In the GnRH group, LH increased (P<0.0001) between hours 0 and 0.25 and then progressively decreased; concentration of LH was not affected in the saline and hCG groups. Progesterone concentration was not different among groups. In the GnRH group, RI tended (P<0.07) to decrease between hours 0 and 1.5 and increased (P<0.01) between hours 1.5 and 4. In the hCG group, two transient RI decreases (P<0.05) occurred before hour 2. The percentage change from hour 0 in the percentage of CL with blood-flow signals was greater at hour 0.5 in the GnRH group than in the saline group and was intermediate in the hCG group. The similarity among groups in progesterone concentration indicated that changes in progesterone were not involved in the GnRH and hCG stimulation of ovarian vascular perfusion. Effects of treatment might have been mediated through LH; however, since hCG biological activity is primarily LH-like, the differences in timing and degree of ovarian and luteal blood flow changes after GnRH or hCG administration in the present study suggest that GnRH might have a direct effect on ovarian blood vessels and vascular control.
Copyright © 2016. Published by Elsevier B.V.
Publication Date: 2016-11-23 PubMed ID: 27908671DOI: 10.1016/j.anireprosci.2016.11.010Google Scholar: Lookup
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- Journal Article
Summary
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The research investigates how certain reproductive hormones affect the blood flow in ovarian and luteal bodies in diestrous mares. The study found that while both Gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) induced changes in blood flow, the effects were timed differently, suggesting possible direct influence by GnRH on ovarian blood vessels.
Objective
- The main objective of this study was to examine the impact of reproductive hormones (such as GnRH, hCG, LH, and progesterone) on the regulation of blood flow in the corpus luteum (CL) and ovaries.
Method
- Mares in the stage of their sexual cycle known as diestrus were given a single dose of saline, 100μg gonadorelin (GnRH), or 1500IU hCG, 10 days after ovulation.
- Plasma LH and progesterone concentrations were measured, along with resistance index (RI) for the blood flow in ovarian arteries, and the percentage of CL with blood flow signals. These measurements were taken just before treatment and at nine different time points post-treatment, for six hours.
Findings
- In the GnRH group, LH levels noticeably increased then gradually declined. This change was not observed in the saline and hCG groups.
- The progesterone concentration remained consistent across the groups indicating the changes in progesterone were not contributing to the GnRH and hCG induced increases in ovarian vascular perfusion.
- The GnRH group saw a temporary drop, then a rise in RI, while in the hCG group, two RI decreases occurred before the 2-hour post-treatment mark.
- A greater percentage change in CL with blood flow signals from the start hour was observed at the 30-minutes post-treatment mark in the GnRH group compared to the saline group, with the hCG group showing an intermediate percentage change.
Conclusions
- Although it might appear that the effects are mediated through LH, since hCG also acts in a similar way to LH, the varying timing and degree of blood flow alterations after GnRH or hCG treatment suggest that GnRH may directly affect ovarian blood vessels and vascular control.
Cite This Article
APA
Brito LF, Baldrighi JM, Wolf CA, Ginther OJ.
(2016).
Effect of GnRH and hCG on progesterone concentration and ovarian and luteal blood flow in diestrous mares.
Anim Reprod Sci, 176, 64-69.
https://doi.org/10.1016/j.anireprosci.2016.11.010 Publication
Researcher Affiliations
- Eutheria Foundation, Cross Plains, WI, 53528, USA.
- Eutheria Foundation, Cross Plains, WI, 53528, USA.
- Eutheria Foundation, Cross Plains, WI, 53528, USA; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, 53706, USA.
- Eutheria Foundation, Cross Plains, WI, 53528, USA; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, 53706, USA. Electronic address: ginther@vetmed.wisc.edu.
MeSH Terms
- Animals
- Chorionic Gonadotropin / administration & dosage
- Chorionic Gonadotropin / pharmacology
- Diestrus / blood
- Diestrus / drug effects
- Diestrus / physiology
- Female
- Gonadotropin-Releasing Hormone / administration & dosage
- Gonadotropin-Releasing Hormone / pharmacology
- Horses
- Luteinizing Hormone
- Ovary / blood supply
- Ovary / physiology
- Progesterone / blood
- Progesterone / metabolism
Citations
This article has been cited 2 times.- Jiang J, Gao S, Han T. Study on the Influencing Mechanism of Human Chorionic Gonadotropin (hCG) on Oocyte Maturation in Patients with Polycystic Ovary Syndrome.. Comput Math Methods Med 2022;2022:7933166.
- Piotrowska-Tomala KK, Jonczyk AW, Szóstek-Mioduchowska AZ, Żebrowska E, Ferreira-Dias G, Skarzynski DJ. The Effects of Prostaglandin E(2) Treatment on the Secretory Function of Mare Corpus Luteum Depends on the Site of Application: An in vivo Study.. Front Vet Sci 2021;8:753796.
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