Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Temporal and spatial associations of oestrogen receptor alpha and progesterone receptor in the endometrium of cyclic and early pregnant mares.
Abstract: Uterine function is primarily controlled by the combined actions of oestrogen and progesterone working through their cognate nuclear receptors. The mechanism of establishment of pregnancy in the mare is of interest because it involves prolonged pre-attachment and conceptus migration phases, and both invasive and non-invasive placental cell types, and as such has been an important comparative model. This study characterised regulation of oestrogen (ER) and progesterone (PR) receptors in the endometrium of the mare during the oestrous cycle and early pregnancy. Endometrial tissues collected during the oestrous cycle and early pregnancy were analysed for steady-state levels of ER and PR mRNA and protein. Steady-state levels of ER and PR mRNA were highest on days 0, 17 and 20 in cyclic mares and lowest on days 11 and 14. A day-by-status interaction was detected, indicating that day 17 and day 20 pregnant mares exhibited low levels of ER and PR compared with the corresponding days of the oestrous cycle. In situ hybridisation analyses showed receptor mRNA localisation primarily in the luminal epithelium (LE), glandular epithelium (GE) and stroma around oestrus. During dioestrus and early pregnancy, receptors were not detected in the LE, and were lower in the stroma and deeper GE. Changes in hybridisation intensity in these cell types were consistent with changes in mRNA levels detected by slot-blot hybridisation. ER and PR proteins were detected in the nuclei of LE, GE and stromal cells. Consistent with results from in situ hybridisation, levels of ER and PR immunoreactivity were higher around oestrus, declined to low levels during dioestrus and remained low during early pregnancy. Results described here for temporal and spatial changes in steroid receptor gene expression in mares show the greatest similarities with those described for cattle and sheep.
Publication Date: 2005-07-29 PubMed ID: 16049162DOI: 10.1530/rep.1.00596Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- N.I.H.
- Extramural
- Research Support
- U.S. Gov't
- P.H.S.
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research article discusses a study that investigates the way estrogen and progesterone receptors in the endometrium interact in mares, during their estrous cycle and early pregnancy. The main findings indicate variations in these receptors during different stages, with the highest concentration on specific days.
Objective of the Research
The study aimed to understand how the combined actions of estrogen and progesterone, two hormones that control uterine function, work through their respective receptors in mares. The researchers were interested in this mechanism because establishing pregnancy in mares involves a complex process—prolonged pre-attachment, conceptus migration, and both invasive and non-invasive placental cell types.
Methodology
The researchers:
- Collected and assessed endometrial tissues during the estrous cycle and early pregnancy for steady-state levels of estrogen receptor (ER) and progesterone receptor (PR) mRNA and protein.
- Used in situ hybridization analyses to identify where receptor mRNA was primarily located.
- Examined levels of ER and PR immunoreactivity at various stages.
Findings
The study revealed that:
- The highest levels of ER and PR mRNA were found on days 0, 17, and 20 in cyclic mares, while the lowest levels were observed on days 11 and 14.
- Day 17 and day 20 pregnant mares exhibited lower levels of ER and PR compared to the equivalent days of the estrous cycle.
- Receptor mRNA mainly existed in the luminal epithelium (LE), glandular epithelium (GE), and stroma around estrus.
- During dioestrus and early pregnancy, receptors are undetectable in the LE, and decreased in the stroma and deeper GE.
- Fluctuations in hybridization intensity in these cell types were consistent with changes in mRNA levels detected by slot-blot hybridization.
Conclusion
The variations in the levels and locations of receptor mRNA and protein at different stages of the estrous cycle and early pregnancy were consistent with previous data from similar studies on cattle and sheep. The study provides important insights into the hormonal control of mare reproduction, and may serve as a reference model for further research.
Cite This Article
APA
Hartt LS, Carling SJ, Joyce MM, Johnson GA, Vanderwall DK, Ott TL.
(2005).
Temporal and spatial associations of oestrogen receptor alpha and progesterone receptor in the endometrium of cyclic and early pregnant mares.
Reproduction, 130(2), 241-250.
https://doi.org/10.1530/rep.1.00596 Publication
Researcher Affiliations
- Department of Animal and Veterinary Science, Center for Reproductive Biology, University of Idaho, Moscow, Idaho 83844-2330, USA.
MeSH Terms
- Animals
- Blotting, Northern / methods
- Endometrium / chemistry
- Estrogen Receptor alpha / analysis
- Estrogen Receptor alpha / genetics
- Estrous Cycle / metabolism
- Female
- Horses / metabolism
- Immunohistochemistry / methods
- In Situ Hybridization / methods
- Pregnancy
- Pregnancy, Animal / metabolism
- RNA, Messenger / analysis
- Receptors, Progesterone / analysis
- Receptors, Progesterone / genetics
Grant Funding
- P20-RR15587-01 / NCRR NIH HHS
Citations
This article has been cited 17 times.- Newcombe JR, Cuervo-Arango J, Wilsher S. The Timing of the Maternal Recognition of Pregnancy Is Specific to Individual Mares. Animals (Basel) 2023 May 22;13(10).
- Zdrojkowski Ł, Jasiński T, Ferreira-Dias G, Pawliński B, Domino M. The Role of NF-κB in Endometrial Diseases in Humans and Animals: A Review. Int J Mol Sci 2023 Feb 2;24(3).
- Jasiński T, Zdrojkowski Ł, Ferreira-Dias G, Kautz E, Juszczuk-Kubiak E, Domino M. Molecular Mechanism of Equine Endometrosis: The NF-κB-Dependent Pathway Underlies the Ovarian Steroid Receptors' Dysfunction. Int J Mol Sci 2022 Jul 1;23(13).
- Lawson EF, Grupen CG, Baker MA, Aitken RJ, Swegen A, Pollard CL, Gibb Z. Conception and early pregnancy in the mare: lipidomics the unexplored frontier. Reprod Fertil 2022 Jan 1;3(1):R1-R18.
- Segabinazzi LGTM, Andrade LRP Jr, Alvarenga MA, Dell'Aqua JA Jr, Canisso IF. Use of Intravaginal Progesterone-Releasing Device Results in Similar Pregnancy Rates and Losses to Long-Acting Progesterone to Synchronize Acyclic Embryo Recipient Mares. Vet Sci 2021 Sep 10;8(9).
- Beguelini MR, Santiago CS, Guerra LHA, Santos FCA, Góes RM, Morielle-Versute E, Taboga SR. The hormonal control of the uterus of the bat Myotis nigricans during its different reproductive phases: emphasis on progesterone and estradiol. Cell Tissue Res 2021 Apr;384(1):211-229.
- Schöniger S, Schoon HA. The Healthy and Diseased Equine Endometrium: A Review of Morphological Features and Molecular Analyses. Animals (Basel) 2020 Apr 5;10(4).
- Smits K, Willems S, Van Steendam K, Van De Velde M, De Lange V, Ververs C, Roels K, Govaere J, Van Nieuwerburgh F, Peelman L, Deforce D, Van Soom A. Proteins involved in embryo-maternal interaction around the signalling of maternal recognition of pregnancy in the horse. Sci Rep 2018 Mar 27;8(1):5249.
- Tachibana Y, Sakurai T, Bai H, Shiota K, Nambo Y, Nagaoka K, Imakawa K. RNA-seq analysis of equine conceptus transcripts during embryo fixation and capsule disappearance. PLoS One 2014;9(12):e114414.
- Geisert RD, Lucy MC, Whyte JJ, Ross JW, Mathew DJ. Cytokines from the pig conceptus: roles in conceptus development in pigs. J Anim Sci Biotechnol 2014;5(1):51.
- Yoshinaga K, Davies C, White K, Caron K, Golos T, Fazleabas A, Paria B, Mor G, Paul S, Ye X, Dey SK, Spencer T, Roberts RM. Interdisciplinary collaborative team for blastocyst implantation research: inception and perspectives. Am J Reprod Immunol 2014 Jan;71(1):1-11.
- Geisert R, Fazleabas A, Lucy M, Mathew D. Interaction of the conceptus and endometrium to establish pregnancy in mammals: role of interleukin 1β. Cell Tissue Res 2012 Sep;349(3):825-38.
- Kalpokas I, Perdigón F, Rivero R, Talmon M, Sartore I, Viñoles C. Effect of a povidone-iodine intrauterine infusion on progesterone levels and endometrial steroid receptor expression in mares. Acta Vet Scand 2010 Dec 16;52(1):66.
- Ross JW, Ashworth MD, Mathew D, Reagan P, Ritchey JW, Hayashi K, Spencer TE, Lucy M, Geisert RD. Activation of the transcription factor, nuclear factor kappa-B, during the estrous cycle and early pregnancy in the pig. Reprod Biol Endocrinol 2010 Apr 28;8:39.
- Alm YH, Sukjumlong S, Kindahl H, Dalin AM. Steroid hormone receptors ERalpha and PR characterised by immunohistochemistry in the mare adrenal gland. Acta Vet Scand 2009 Jul 22;51(1):31.
- Dehury S, Uppal V, Pathak D, Gupta A. Seasonal modulation of progesterone receptor, PCNA, and enzyme activity in buffalo uterus: implications for endometrial growth during oestrous. Trop Anim Health Prod 2025 Jun 26;57(6):289.
- Wong YS, Mançanares AC, Navarrete FI, Poblete PM, Méndez-Pérez L, Ferreira-Dias GML, Rodriguez-Alvarez L, Castro FO. Mare stromal endometrial cells differentially modulate inflammation depending on oestrus cycle status: an in vitro study. Front Vet Sci 2023;10:1271240.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
