Concentrations of progesterone and a PGF2α metabolite during the interovulatory interval compared to the corresponding days of pregnancy in mares

Castro, T.; Jacob, Jerry; Stefani, G.; Domingues, Rafael R.; Ginther, O.J.

doi:10.1016/j.theriogenology.2021.02.004

Cited by 6 publications

(3 citation statements)

References 55 publications

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“…The lack of a distinct increase in the classical machinery for synthesis, transport, and metabolism ( OXTR, COX-2, PTGFS, SLCO2A1, and HPGD ) of PGF2α indicates that the nonpregnant mares in the study had not started luteolysis. This is further supported by findings from our previous study in which concentrations of P4 from the same breed of horse were not different between pregnant and nonbred mares until the beginning of luteolysis on mean D13 68 .…”

Section: Discussionsupporting

confidence: 86%

Embryo-endometrial interaction associated with the location of the embryo during the mobility phase in mares

de Castro,

van Heule,

Domingues

et al. 2024

Sci Rep

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Embryo-maternal crosstalk is essential to establish pregnancy, with the equine embryo moving throughout the uterus on days 9–15 (ovulation = day 0) as part of this interaction. We hypothesized that the presence of a mobile embryo induces local changes in the gene expression of the endometrium. On Day 12, the endometrial transcripts were compared among three groups: uterine horn with an embryo (P+, n = 7), without an embryo (P−, n = 7) in pregnant mares, and both uterine horns of nonbred mares (NB, n = 6). We identified 1,101 differentially expressed genes (DEGs) between P+ vs. NB and 1,229 DEGs between P− vs. NB. The genes upregulated in both P+ and P− relative to NB were involved in growth factor pathway and fatty acid activation, while downregulated genes were associated with oxytocin signaling pathway and estrogen receptor signaling. Comparing the transcriptome of P+ to that of P−, we found 59 DEGs, of which 30 genes had a higher expression in P+. These genes are associated with regulating vascular growth factors and the immune system, all known to be essential in early pregnancy. Overall, this study suggests that the mobile embryo influences the endometrial gene expression locally.

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Section: Discussionsupporting

confidence: 86%

Embryo-endometrial interaction associated with the location of the embryo during the mobility phase in mares

de Castro,

van Heule,

Domingues

et al. 2024

Sci Rep

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“…In the non-pregnant cyclic mare, progesterone concentrations begin to fall approximately 14 days after ovulation, which is coincidental with maximal levels of prostaglandin (PGF2α), measured by the presence of its metabolite (PGFM) in the uterine vein, uterine lumen and endometrium [3][4][5][6][7][8][9]. In addition, the enzyme responsible for the release of arachidonic acid, and hence the initiator of the release of PGF2α, is highest in non-pregnant mares at day 14 [10].…”

Section: Introductionmentioning

confidence: 99%

The Timing of the Maternal Recognition of Pregnancy Is Specific to Individual Mares

Newcombe¹,

Cuervo‐Arango

Wilsher

2023

Animals

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The present experiment aimed at determining whether the timing of the maternal recognition of pregnancy (MRP) was specific to individual mares by determining when luteostasis, a failure to return to oestrus, reliably occurred in individuals following embryo reduction. Singleton (n = 150) and synchronous twin pregnancies (n = 9) were reduced in 10 individuals (5–29 reductions/mare) at pre-determined time points within days 10 (n = 20), 11 (n = 65), 12 (n = 47), 13 (n = 12) or 14 (n = 15) of pregnancy. Prior to embryo reduction, the vesicle diameter was measured in 71% (106/150) of the singleton pregnancies. The interovulatory interval (IOI) was recorded on 78 occasions in seven of the mares in either non-pregnant cycles (n = 37) or those in which luteolysis followed embryo reduction (n = 41). The earliest time post-ovulation at which the embryo reduction resulted in luteostasis in an individual was 252 h (mid-Day 10). Consistency in luteostasis following embryo reduction showed individual variation between mares (272–344 h). Binary logistic regression analysis showed an individual mare effect (p < 0.001) and an effect of the interval post-ovulation at which embryo reduction was undertaken (p < 0.001). However, there was no significant effect of vesicle diameter at the time of embryo reduction (p = 0.099), nor a singleton or twin pregnancy (p = 0.993), on the dependent of luteolysis or luteostasis. The median IOI between individual mares varied significantly (p < 0.05) but was not correlated to the timing of MRP. The timing of MRP varied between the mares but was repeatable in each individual. The factors and mechanisms underlying the individuality in the timing of MRP were not determined and warrant further study.

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“…The published literature focuses on the significant differences between jennies, mares, and ponies, but although one study has described some characteristics of early pregnancy in jennies [ 7 ]; none fully define the daily progression of jennies’ early pregnancy. In horses, the use of ultrasonography to evaluate pregnancy development and fetal wellbeing has been well described, since 1980 [ 10 , 11 ], and endocrinology during gestation has been extensively studied in mares [ 12 , 13 ]. However, there is a lack of information regarding jennies’ pregnancy, and horse guidelines are often applied for this species [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Early Pregnancy in Jennies in the Caribbean: Corpus Luteum Development and Progesterone Production, Uterine and Embryo Dynamics, Conceptus Growth and Maturation

Segabinazzi

Roberts

Peterson

et al. 2022

Animals

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We aimed to characterize early embryo development and changes in corpus luteum (CL) development and progesterone profile in pregnant vs. non-pregnant jennies. Eight jennies were enrolled in the study. In the first two cycles, the jennies were monitored by transrectal ultrasonography and had blood harvested for hormone profile assay. In the third cycle, jennies were bred by a jack of proven fertility. Jennies were then monitored and sampled for up to 30 days of pregnancy. Data were evaluated by random-effects multiple linear regression, and correlations were expressed as Pearson’s correlation coefficient. Progesterone concentration rose rapidly from ovulation (D0) until D7, plateaued until D12–14, then precipitously declined between D14 and 15, remaining low until the next ovulation in non-pregnant cycles. In the pregnant jennies, the progesterone concentration rose to maximal concentrations on D7–11, being higher at this stage than in non-pregnant cycles, then declined gradually up to D30. In all cycles, the volume of the CL increased steadily until D6, when it plateaued in pregnant jennies. For non-pregnant jennies, CL volume decreased slowly from D6 to D11 and then had a faster drop. Uterine tone increased following ovulation, becoming turgid around the day of embryo fixation (D15.0 ± 0.9). An embryonic vesicle (EV) was first detected on D9.3 ± 0.5 (2.4 ± 0.5 mm). The EV remained spherical until D18.6 ± 1.4. The embryo proper was first detected ventrally in the vesicle on D20.8 ± 1.1 and the embryonic heartbeat by D22.0 ± 0.9. The allantoic sac was identified at D24.0 ± 0.9, and at D30, the allantoic sac filled the ventral half of the EV. This study provides evidence that higher cumulative concentrations of progesterone are correlated to size of the EV, and there were changes in the luteal dynamics and progesterone profiles in pregnant vs. non-pregnant jennies.

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Concentrations of progesterone and a PGF2α metabolite during the interovulatory interval compared to the corresponding days of pregnancy in mares

Cited by 6 publications

References 55 publications

Embryo-endometrial interaction associated with the location of the embryo during the mobility phase in mares

Embryo-endometrial interaction associated with the location of the embryo during the mobility phase in mares

The Timing of the Maternal Recognition of Pregnancy Is Specific to Individual Mares

Early Pregnancy in Jennies in the Caribbean: Corpus Luteum Development and Progesterone Production, Uterine and Embryo Dynamics, Conceptus Growth and Maturation

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