The effects of dexamethasone and prednisolone on pituitary and ovarian function in the mare.
Abstract: Persistent mating induced endometritis is among the most common causes of infertility in the mare. Recently, improved pregnancy rates have been reported when corticosteroids were administered to 'problem mares' specifically, to modulate the post mating inflammatory response; however, the effect of treatment on pituitary and ovarian function requires further study. Objective: To evaluate the effects of prolonged treatment with glucocorticoids on pituitary and ovarian function. Methods: Eighteen cycling Quarter Horse mares in early oestrus were assigned randomly to one of 3 treatment groups: dexamethasone 0.05 mg/kg bwt i.v. twice a day, prednisolone 0.5 mg/kg per os twice a day, or placebo for 5 days. Mares were examined by ultrasound daily to evaluate reproductive function. Blood samples were collected daily to measure luteinising hormone (LH), progesterone and cortisol levels. Results: Dexamethasone treatment caused greater (P<0.05) suppression of endogenous cortisol concentration (9.4 +/- 1.1 ng/ml) compared to prednisolone- (41.9 +/- 4.0 ng/ml) or placebo-treated mares (32.4 +/- 3.8 ng/ml). After 24 h, mares treated with dexamethasone exhibited lower uterine oedema scores than prednisolone- or placebo-treated mares. An ovulation rate of 40% was observed in dexamethasone-treated mares (2/5) compared to 83% for prednisolone (5/6) and 100% for placebo-treated (6/6) mares. An absence of a LH surge was noted in 3 of 5 dexamethasone-treated mares and one of 6 prednisolone-treated mares. Conclusions: Repeated administration of dexamethasone to mares in oestrus is associated with decreased uterine oedema, suppression of LH and a high rate of ovulation failure. It is recommended that dexamethasone treatment is limited to only 1 or 2 days and that a lower dose is considered in the management of persistent mating induced endometritis to avoid potential adverse affects on reproductive function.
Publication Date: 2010-07-20 PubMed ID: 20636781DOI: 10.1111/j.2042-3306.2010.00034.xGoogle Scholar: Lookup
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- Journal Article
- Randomized Controlled Trial
Summary
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The researchers in this article aimed to assess the impacts of the prolonged use of glucocorticoids, specifically dexamethasone and prednisolone, on a mare’s pituitary and ovarian functions. They found that using dexamethasone results in decreased uterine swelling, LH suppression, and a high ovulation failure rate, indicating possible adverse effects on a mare’s reproductive function when used for treating endometritis induced by ongoing mating.
Research Methodology
- Eighteen cycling Quarter Horse mares in their early oestrus stages were selected and divided randomly into three groups. Each group was subjected to different treatments for five days, which were dexamethasone, prednisolone, and a placebo.
- The dexamethasone group was given a dosage of 0.05 mg/kg body weight intravenously twice a day. The prednisolone group was orally administered a dosage of 0.5 mg/kg twice a day.
- Throughout the course of treatment, the mares were regularly evaluated through ultrasound scans to track their reproductive function. Blood samples were also taken daily to measure the levels of luteinising hormone (LH), progesterone, and cortisol in their bodies.
Findings
- The study found that dexamethasone treatment significantly reduced the concentration of endogenous cortisol compared to prednisolone or placebo treatments.
- After 24 hours of treatment, mares who were treated with dexamethasone showed decreased uterine edema scores compared to the other two groups.
- The rate of ovulation was observed to be significantly lower (40%) in the dexamethasone group compared to the prednisolone (83%) and placebo groups (100%).
- A lack of a LH surge was reported in three out of five mares in the dexamethasone group and one out of six mares in the prednisolone group.
Conclusion
- The study concludes that prolonged use of dexamethasone in mares during oestrus leads to decreased uterine oedema, impeded LH surge, and a high rate of ovulation failure. Thus, suggesting dexamethasone can have a negative impact on the mare’s reproductive health.
- Based on these findings, the researchers recommended limiting dexamethasone administration to just one or two days and considering reducing the dosage when managing persistent mating induced endometritis. This is to avoid any potential adverse effects on the mare’s reproductive function.
Cite This Article
APA
Ferris RA, McCue PM.
(2010).
The effects of dexamethasone and prednisolone on pituitary and ovarian function in the mare.
Equine Vet J, 42(5), 438-443.
https://doi.org/10.1111/j.2042-3306.2010.00034.x Publication
Researcher Affiliations
- Equine Reproduction Laboratory, Colorado State University, USA. ryan.ferris@colostate.edu
MeSH Terms
- Adrenal Glands / drug effects
- Animals
- Dexamethasone / pharmacology
- Estrus / drug effects
- Estrus / physiology
- Female
- Glucocorticoids / pharmacology
- Horses / physiology
- Ovary / drug effects
- Ovary / physiology
- Pituitary Gland / drug effects
- Pituitary Gland / physiology
- Prednisolone / pharmacology
- Time Factors
Citations
This article has been cited 3 times.- Kikuchi M, Nagata SI, Ishige T, Minamijima Y, Hirota KI, Tozaki T, Kakoi H, Kizaki K. Evaluation of the effect of glucocorticoid treatment on adrenocortical functions by monitoring endogenous hydrocortisone in horses.. J Vet Med Sci 2023 Jun 13;85(6):647-652.
- Satué K, Fazio E, Muñoz A, Medica P. Endocrine and Electrolyte Balances during Periovulatory Period in Cycling Mares.. Animals (Basel) 2021 Feb 17;11(2).
- Canisso IF, Segabinazzi LGTM, Fedorka CE. Persistent Breeding-Induced Endometritis in Mares - a Multifaceted Challenge: From Clinical Aspects to Immunopathogenesis and Pathobiology.. Int J Mol Sci 2020 Feb 20;21(4).
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