Temporal and spatial associations of oestrogen receptor alpha and progesterone receptor in the endometrium of cyclic and early pregnant mares

Hartt, L S; Carling, Stacy; Joyce, Margaret M.; Johnson, Greg A.; Vanderwall, Dirk K.; Ott, Troy L.

doi:10.1530/rep.1.00596

Cited by 64 publications

(71 citation statements)

References 21 publications

(42 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In our in vitro tissue culture system, however, endometrial STC1 expression was not regulated by E2 and/or progesterone treatments, while IL1RA had been increased by the same treatment in our previous study [24]. Low levels of progesterone receptor contents found in the equine endometrium during early pregnancy [49] also suggest that progesterone treatment may not be effective in upregulating STC1 expression. It should be noted that the upstream region of the STC1 gene does not contain any steroid receptor binding sites, indicating the STC1 gene expression may not be directly regulated by E2 and/or progesterone.…”

Section: Discussioncontrasting

confidence: 53%

Production of Calcium Maintenance Factor Stanniocalcin-1 (STC1) by the Equine Endometrium During the Early Pregnant Period

Kikuchi

Nakano

Nambo

et al. 2011

Journal of Reproduction and Development

View full text Add to dashboard Cite

Abstract.A factor responsible for progression to pregnancy establishment in the mare has not been definitively characterized. To identify factors possibly involved in the establishment of equine pregnancy, the endometrium was collected from day 13 (day 0=day of ovulation) cyclic and day 13, 19 and 25 pregnant animals. From initial subtractive hybridization studies, a calcium regulating factor, Stanniocalcin-1 (STC1) mRNA, was found as a candidate molecule expressed uniquely in the pregnant endometrium. Endometrial expression of STC1 mRNA was noted on day 19 and was markedly increased in the day 25 gravid endometrium. STC1 protein was found in the extracts of day 25 gravid endometrium and immunochemically localized in the uterine glands. In addition, STC1 protein was detected in uterine flushing media collected from day 25 pregnant mares. High concentrations of estradiol-17β (E2) were detected in day 25 conceptuses. E2 levels were much higher in the gravid endometrium than in other regions, whereas progesterone levels did not differ among the samples from different endometrial regions. Expression of STC1 mRNA, however, was not significantly upregulated in cultured endometrial explants treated with various concentrations of E2 (0.01-100 ng/ml) with or without 10 ng/ml progesterone. These results indicate that an increase in STC1 expression appears to coincide with capsule disappearance in the conceptus, and suggest that STC1 from the uterine glands likely plays a role in conceptus development during the pregnancy establishment period in the mare. Key words: Endometrium, Equine, Estradiol-17β, Stanniocalcin-1 (STC1), Uterine secretion (J. Reprod. Dev. 57: [203][204][205][206][207][208][209][210][211] 2011) he establishment of equine pregnancy is a unique and long process, during which a series of physical and possibly biochemical interactions are required between the conceptus and uterus. The equine conceptus first enters into the uterus on days 6-8 of pregnancy (day 0=day of ovulation) [1] and then begins to transmigrate throughout the entire uterine body and horns until approximately day 16 of pregnancy [2][3][4]. The frequency at which a conceptus moves from one uterine horn to another increases up to 10-20 times per day [5]. The conceptus ceases migration and lodges at the caudal portion of one of the uterine horns, known as "fixation", on approximately days 16-18 of pregnancy [2]. Between days 11 and 16 of pregnancy, the conceptus rapidly expands its volume, but keeps its spherical shape surrounded by a unique, smooth structure called a "capsule" [6,7] that emerges beneath the zona pellucida on days 6-8 of pregnancy. The capsule is an acellular mucin-like glycoprotein [8] that is structurally strong and is considered essential for the survival of the conceptus and continuation of pregnancy [9,10]. Together with peristaltic myometrial contractions, the capsule is likely to give motility to the conceptus, although the precise stimulus for conceptus migration is unknown. Thereafter, the capsule disappears by d...

show abstract

Section: Discussioncontrasting

confidence: 53%

Production of Calcium Maintenance Factor Stanniocalcin-1 (STC1) by the Equine Endometrium During the Early Pregnant Period

Kikuchi

Nakano

Nambo

et al. 2011

Journal of Reproduction and Development

View full text Add to dashboard Cite

show abstract

“…The expressions of both receptors changed signifi- cantly during the cycle, with highest values on day 15 (ERα) and day -3 (ERα and ERβ). However, in a previous study [32], the ERα mRNA levels in 25 mares were similar during estrus and on days 5, 10 or 15 of the cycle, whereas in other studies [33,34], the levels were highest around estrus and low during mid-to latediestrus. Clearly, additional studies are needed to resolve these apparent discrepancies.…”

Section: Discussionmentioning

confidence: 66%

Relationships Between Uterine Blood Flow, Peripheral Sex Steroids, Expression of Endometrial Estrogen Receptors and Nitric Oxide Synthases During the Estrous Cycle in Mares

Honnens¹,

Weisser²,

Welter

et al. 2011

J. Reprod. Dev.

View full text Add to dashboard Cite

Abstract. The objective of this study was to investigate the relationships between uterine perfusion and estrogen, progesterone and the uterine nitric oxide synthase (NOS) system in five trotter mares during the estrous cycle. Color Doppler sonography for measurement of uterine blood flow and collection of blood for determination of plasma estrogen and progesterone concentrations were performed on days 0 (= ovulation), 1, 5, 11 and 15 and daily during estrus (days -1 to -4) of one estrous cycle; endometrial biopsy collection for mRNA expression analysis of NOS and estrogen receptors was performed on days 0, 1, 5, 11, 15 and -3. Blood flow in each uterine artery was assessed by calculating the mean time-averaged maximum velocity (TAMV) and the pulsatility index (PI). Plasma concentrations of estrogen and progesterone were determined using specific enzyme immunoassays. The mRNA expressions of endothelial NOS (eNOS), inducible NOS (iNOS) as well as estrogen receptors α (ERα) and β (ERβ) were quantified using reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. The TAMV and PI had a biphasic pattern during the estrous cycle (P<0.05), with maximum and minimum, respectively, values on days 5 and -4. Estrogen receptor mRNA concentrations increased significantly during days 15 (ERα) and -3 (ERβ). Transcript expression of eNOS, but not iNOS, had a biphasic pattern during the cycle (P<0.05) with maximum levels on days 5 and -3 and correlated positively with TAMV (r=0.81, P=0.05). We infer that the uterine NOS system, especially eNOS, plays an important role in the regulation of uterine blood flow during the estrous cycle in mares. Key words: Endometrial messenger RNA expression, Estrous cycle, Nitric oxide synthases, Steroid hormones, Uterine perfusion (J. Reprod. Dev. 57: [43][44][45][46][47][48] 2011) haracteristic uterine blood flow patterns have been reported during the estrous cycle in mares based on color Doppler sonography [1,2]. Uterine perfusion had a wave-shaped profile throughout the cycle, showing maximal blood flow during estrus and the early luteal phase [1][2][3][4]. Variations in uterine blood flow in cycling mares have been attributed to changes in circulating estrogen concentrations. However, due to a weak correlation between the resistance to uterine blood flow and plasma estrogen concentrations, other factors may also regulate uterine blood flow [2].Changes in uterine blood flow during the estrous cycle in many species are mediated mainly by estrogens [5]; although flow was enhanced by high plasma estradiol concentrations [6,7] and decreased during the luteal phase [8,9], the mechanisms involved have not been elucidated. Estrogens appear to act via two pathways: the genomic and non-genomic pathways [10]. Briefly, in the classical genomic pathway, estrogens bind to their nuclear receptors, subsequently regulating the transcription of target genes. For example, administration of estradiol increased estrogen receptors within 48 h in cyclic ewes [11]. Furthermore, a non-genomic pathway wit...

show abstract

“…It has been postulated that progesterone acts on the PGRpositive stroma during pregnancy, which in turn produces paracrine factors that act upon the PGR negative luminal epithelium . During early pregnancy in the mare, a similar pattern of temporal and spatial expression of PGR and ESR1 in the endometrium can be observed, as expression of both receptors is highest during estrus and declines under the infl uence of progesterone following ovulation (de Ruijter- Villani et al 2014 ;Hartt et al 2005 ;McDowell et al 1999 ;Tomanelli et al 1991 ;Watson et al 1992 ). Similar to sheep, expression of these receptors is primarily downregulated in the luminal epithelium, whereas the deep glandular epithelium and stroma retain low expression levels (de Ruijter- Villani et al 2014 ;Hartt et al 2005 ).…”

Section: Spatial and Temporal Regulation Of Endometrial Receptors Formentioning

confidence: 89%

Pregnancy Recognition and Implantation of the Conceptus in the Mare

Klein

2015

Regulation of Implantation and Establishment of Pregnancy in Mammals

View full text Add to dashboard Cite

Few, if any, biological processes are as diverse among domestic species as establishment of early pregnancy, in particular maternal recognition of pregnancy. Following fertilization and initial development in the mare oviduct, selective transport of the embryo through the uterotubal junction driven by embryo-derived PGE2 occurs. Upon arrival in the uterus, an acellular glycoprotein capsule is formed that covers the embryo, blastocyst, and conceptus (embryo and associated extraembryonic membranes) between the second and third weeks of pregnancy. Between Days 9 and 15/16 of pregnancy, the conceptus undergoes an extended phase of mobility. Conceptus mobility is driven by conceptus-derived PGF2α and PGE2 that stimulate uterine contractions which in turn propel migration of the conceptus within the uterine lumen. Cessation of conceptus mobility is referred to as fixation and appears to be attributable to increasing size of the conceptus, preferential thickening of the endometrium near the mesometrial attachment referred to as encroachment, and a reduction in sialic acid content of the capsule. During maternal recognition of pregnancy, endometrial PGF2α release is attenuated, a consequence of reduced expression of key enzymes involved in prostaglandin production. Oxytocin responsiveness is altered during early pregnancy, and reduced expression of the oxytocin receptor appears to be regulated at the posttranscriptional level rather than the transcriptional level. Prostaglandin release is attenuated temporarily only during early pregnancy; during the third week of pregnancy, the endometrium resumes the ability to secrete PGF2α. The equine conceptus initiates steroidogenesis as early as Day 6 and synthesizes estrogens, androgens, and progesterone. Estrogens are metabolized locally, presumably regulating their bioavailability and actions. Results of experiments attempting to prove that conceptus-derived estrogens are responsible for extension of corpus luteum function have been inconclusive. By the fourth week of pregnancy, the chorionic girdle becomes visible on the trophoblast. Subsequent invasion of chorionic girdle cells leads to formation of endometrial cups which secrete equine chorionic gonadotropin. Equine chorionic gonadotropin has luteinizing hormone functions in the mare, causing luteinization of follicles resulting in the formation of secondary corpora lutea essential to production of progesterone and maintenance of pregnancy.

show abstract

Temporal and spatial associations of oestrogen receptor alpha and progesterone receptor in the endometrium of cyclic and early pregnant mares

Cited by 64 publications

References 21 publications

Production of Calcium Maintenance Factor Stanniocalcin-1 (STC1) by the Equine Endometrium During the Early Pregnant Period

Production of Calcium Maintenance Factor Stanniocalcin-1 (STC1) by the Equine Endometrium During the Early Pregnant Period

Relationships Between Uterine Blood Flow, Peripheral Sex Steroids, Expression of Endometrial Estrogen Receptors and Nitric Oxide Synthases During the Estrous Cycle in Mares

Pregnancy Recognition and Implantation of the Conceptus in the Mare

Contact Info

Product

Resources

About