Immunohistochemical localization of oestrogen receptors alpha and beta, progesterone receptor and aromatase in the equine placenta.
Abstract: The functions of placental oestrogens during equine pregnancy are still unclear. Yet, they may act predominantly as local regulators of growth and differentiation in the microplacentomes. Thus, expression patterns of oestrogen receptors (ERs) alpha and beta were investigated in the microcotyledonary placenta from pregnant mares at 110, 121, 179, 199 and 309 days of gestation by immunohistochemistry. In microplacentomes, both the ER isoforms were detected in trophoblast (T) cells, chorionic villous stroma (FS), microcaruncular epithelium (ME) and microcaruncular stroma (MS). Proportions of positive cells were 38-91% (T), 11-41% (FS), 55-89% (ME), 17-51% (MS) for ERalpha and 66-76% (T), 21-37% (FS), 41-68% (ME) and 24-55% (MS) for ERbeta. Between days 110 and 199, proportions of cells positive for progesterone receptor (PR) varied between 19% and 62% (T), 3% and 50% (CS), 15% and 46% (ME), and 4% and 33% (MS). At day 309, PR was virtually absent in T, CS and ME (percentages < 0.1), whereas in MS 14.3% of cells were still positive. The expression of ERs and PR in equine microplacentomes gives evidence for a role of placental steroids as regulators of placental growth, differentiation and function. The detection of ERalpha, ERbeta and PR in foetal and maternal vascular tissue suggests that placental steroids are also involved in the control of placental angiogenesis and /or vascular functions. The co-localization of ERs with aromatase in T suggests auto- or intracrine functions of oestrogens in this cell type.
Publication Date: 2008-09-10 PubMed ID: 18992099DOI: 10.1111/j.1439-0531.2008.01073.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study investigates how certain hormone receptors are spread out in the placenta of a horse at different stages of pregnancy, providing clues as to the roles these hormones play in fetal growth, differentiation and function.
Objective and Methodology
- The study aimed to provide a clearer understanding of the roles of placental oestrogens during equine pregnancy.
- The researchers used immunohistochemistry to track expression patterns of oestrogen receptors alpha and beta at various gestation periods (110, 121, 179, 199 and 309 days) in the microcotyledonary placenta of pregnant horses.
- Various types of tissues were investigated including trophoblast cells (T), chorionic villous stroma (FS), microcaruncular epithelium (ME), and microcaruncular stroma (MS).
Findings
- The presence of oestrogen receptors in these tissues suggested that these hormones may primarily serve as local regulators of growth and differentiation in the microplacentomes.
- The proportions of cells positive for these oestrogen receptors varied across different tissues and at different times in gestation.
- The presence of progesterone receptors was substantial during early and mid gestation (days 110 to 199) but was virtually absent by day 309 in most tissues, except for MS, where 14.3% of cells were still positive.
Implications
- The presence and distribution of oestrogen receptors and progesterone receptors in the equine placenta indicate that these hormones likely regulate placental growth, differentiation and function.
- Furthermore, the presence of these receptors in fetal and maternal vascular tissue implies that placental hormones might also influence placental angiogenesis (the formation of new blood vessels) or other vascular functions.
- The researchers also noted the co-location of oestrogen receptors with aromatase (an enzyme that converts androgens to oestrogens) in trophoblast cells, suggesting that the hormones may have a auto- or intracrine (acting within the same cell where they are produced) function in these cells.
Cite This Article
APA
Abd-Elnaeim MM, Derar IR, Wilsher S, Allen WR, Leiser R, Schuler G.
(2008).
Immunohistochemical localization of oestrogen receptors alpha and beta, progesterone receptor and aromatase in the equine placenta.
Reprod Domest Anim, 44(2), 312-319.
https://doi.org/10.1111/j.1439-0531.2008.01073.x Publication
Researcher Affiliations
- Departments of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt.
MeSH Terms
- Animals
- Aromatase / analysis
- Chorionic Villi / chemistry
- Estrogen Receptor alpha / analysis
- Estrogen Receptor beta / analysis
- Estrogens / physiology
- Female
- Gestational Age
- Horses / metabolism
- Immunohistochemistry / veterinary
- Male
- Placenta / blood supply
- Placenta / chemistry
- Placenta / physiology
- Pregnancy
- Progestins / physiology
- Receptors, Progesterone / analysis
- Trophoblasts / chemistry
Citations
This article has been cited 2 times.- Schuler G, Fürbass R, Klisch K. Placental contribution to the endocrinology of gestation and parturition. Anim Reprod 2018 Jul-Sep;15(Suppl 1):822-842.
- Nagy AM, Sathe SR, Atta AH, Hammam AMM, Hsu WH. Characterization of Nuclear Progesterone Receptor Isoforms in the Term Equine Placenta. Front Vet Sci 2021;8:660177.
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