Immunolocalisation of oxytocin in the equine ovary.
Abstract: Oxytocin has been identified in the ovaries of many species
including ruminants (Wathes and Swann 1982; Rodgers et al.
1983), pigs (Jarry etal. 1990), sub-human primates (Khan-Dawood
1998), rats (Ho and Lee 1992) and women (Schaeffer et al. 1984).
In these species ovarian oxytocin has several roles, including
control of luteal regression (Fht and Sheldrick 1983) and possibly
luteinisation (Aladin Chandrase.kher and Fortune 1990; Eispanier et
al. 1997), and involvement in ovulation (viggiano et al. 1989).
In the mare, circulating oxytocin is reported to be high in
oestrus and early dioestrus (Burns et al. 1991), or high in late
dioestrus (Tetzke et al. 1987). Another paper reported that
concentrations remained very low throughout the oestrous cycle
(Stevenson et al. 1991). Short term incubation of cells from equine
preovulatory follicles has failed to yield measurable concentrations
of oxytocin, and follicular fluid and homogenates of corpus luteum
(CL) and follicles contained only low concentrations of the peptide
(Stevenson et al. 1991; Stock et al. 1995). It has been concluded,
therefore, that the ovaries are not a significant source of circulating
oxytocin during the oestrous cycle in mares (Stevenson er al. 199 1).
However, it is possible that even low concentrations of oxytocin
within the mare ovary may have a paracrine or autocrine role in
controlling ovarian function. In the present study,
immunohistochemistry was used to detect and localise oxytocin
within the equine ovary during the oestrous cycle and early
pregnancy. The carrier protein for oxytocin, neurophysin, was also
studied as its presence is taken to represent secretion of oxytocin
outwith the supraopticohypophyseal system (Ciarochi et al. 1985)
Publication Date: 1999-04-23 PubMed ID: 10213431DOI: 10.1111/j.2042-3306.1999.tb03812.xGoogle 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 presence and influence of the hormone oxytocin in horse ovaries during various stages of the reproductive cycle and early pregnancy, through the use of immunohistochemistry. Although previous studies suggest that ovaries may not be a significant source of oxytocin in horses, this study explores the possibility of oxytocin having a paracrine or autocrine role within the ovaries.
Oxytocin and its Roles in Various Species
- The hormone oxytocin has been discovered in the ovaries of numerous species like ruminants, pigs, sub-human primates, rats and humans.
- In these species, oxytocin is responsible for a number of functions such as controlling luteal regression and possibly luteinisation, and aiding in ovulation.
Oxytocin in Horse Ovaries
- Research shows conflicting levels of circulating oxytocin in horses during the estrous cycle. Some studies report high levels during estrus and early diestrus or in late diestrus, while others suggest low concentrations throughout the cycle.
- Previous studies have failed to derive measurable oxytocin concentrations from short-term incubation of cells from preovulatory follicles in horses. Additionally, follicular fluid and homogenates of corpus luteum (CL) and follicles contained only low concentrations of oxytocin, leading to the conclusion that ovaries may not significantly contribute to circulating oxytocin during the estrous cycle in horses.
Examining Possible Paracrine or Autocrine Role of Oxytocin
- Despite the conclusion from previous studies, the research hypothesizes that even low concentrations of oxytocin present in the horse ovaries could perform a paracrine (impacting neighboring cells) or autocrine (impacting the same cell that secreted it) function in regulating ovarian function.
- Immunohistochemistry, a technique that utilizes antibodies to visualize the presence of specific proteins in cells, was used in the study to detect and localize oxytocin in the horse ovaries during different stages of the estrous cycle and early pregnancy.
- The protein neurophysin, which is the carrier protein for oxytocin, was also analyzed because its presence typically indicates the secretion of oxytocin outside of the supraopticohypophyseal system (a part of the brain where oxytocin is mostly synthesized).
Cite This Article
APA
Watson ED, Buckingham J, Björkstén TS.
(1999).
Immunolocalisation of oxytocin in the equine ovary.
Equine Vet J, 31(2), 174-175.
https://doi.org/10.1111/j.2042-3306.1999.tb03812.x Publication
Researcher Affiliations
- Department of Veterinary Clinical Studies, University of Edinburgh, Easter Bush Veterinary Centre, Midlothian, UK.
MeSH Terms
- Animals
- Coloring Agents
- Estrus
- Female
- Horses
- Immunohistochemistry
- Neurophysins / analysis
- Ovary / chemistry
- Oxytocin / analysis
Grant Funding
- Wellcome Trust
Citations
This article has been cited 2 times.- Diel de Amorim M, Dong L, Byron M, Foster RA, Klein C, Saleh M, Saleh T, Card C. Characterization of serum and tissue oxytocinase and tissue oxytocin in the pregnant and non-pregnant mare. Sci Rep 2023 Mar 21;13(1):4616.
- Diel de Amorim M, Klein C, Foster R, Dong L, Lopez-Rodriguez MF, Card C. Expression of Oxytocin/Neurophysin I and Oxytocinase in the Equine Conceptus from Day 8 to Day 21 Post-Ovulation. Animals (Basel) 2022 Mar 22;12(7).
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