Uterine Progesterone Research Articles

Chenodeoxycholic acid fortified diet drives ovarian steroidogenesis to improve embryo implantation through enhancing uterine receptivity via progesterone receptor signaling pathway in rats

Infertility is a worldwide reproductive health problem influenced by the embryo implantation efficiency. We previously revealed that dietary chenodeoxycholic acid (CDCA) positively influence the early embryo implantation. But how CDCA regulate embryo implantation is largely unexplored. Herein, we investigated the mechanism behind CDCA's regulation on embryo implantation in rats. Results showed that CDCA promoted uterine receptivity, leading to increased number of implantation sites. Mechanistically, CDCA reshaped maternal amino acid metabolism and enhanced serum progesterone levels. CDCA enhanced ovarian progesterone synthesis by improving steroidogenesis-related protein (StAR and CYP11A1) expression via Takeda G-protein-coupled receptor 5. Elevated progesterone exaggerated uterine progesterone but weakened the estradiol signaling in the CDCA group, contributing to better uterine receptive for embryo implantation. Additionally, elevated transcription repressor Stat5b induced the down-regulation of progesterone-metabolizing enzyme 20-hydroxysteroid dehydrogenase 20α-HSD, complementally explained uterine progesterone signaling enhancement. Overall, our data revealed that CDCA drove ovarian steroidogenesis to improve embryo implantation through enhancing uterine receptivity via progesterone receptor pathway in rats. Therefore, CDCA diet may be a potential favorable nutritional strategy for infertility and pregnancy management.

SAT376 Luteinizing Hormone Secretion in Hyperandrogenic Girls Taking Spironolactone or Metformin

Abstract Disclosure: C.M. Burt Solorzano: None. M. Gilrain: None. S.H. Kim: None. C.R. McCartney: None. Peri-pubertal hyperandrogenism (HA) typically relates to excess adrenal and/or ovarian androgen production in response to adrenocorticotropin (ACTH) and/or luteinizing hormone (LH), respectively. Spironolactone and metformin are commonly used medications to treat adolescent androgen excess. We examined how end-organ responsiveness and LH pulse patterns are affected by these medications in adolescents with HA. We studied free testosterone (T) levels (including baseline and peaks after ACTH and recombinant human chorionic gonadotropin [r-hCG] stimulation), oral glucose tolerance testing (OGTT), and 12-hr overnight LH secretion (sampled q 10 min) in post-menarcheal girls with HA before and after 3-months of either spironolactone (100 mg BID) or metformin (500 mg BID). Free T was calculated using total T (LC-MS/MS) and sex hormone binding globulin (SHBG).To date, 3 girls (aged 12-18) have been studied using spironolactone and 4 girls (aged 14-17) using metformin. (1 girl was studied twice, once with each medication.) After spironolactone treatment, free T changed by -19% (-58 to +37) (median [range]) unstimulated, by -53% (-62 to -15) after ACTH, and by -54% (-66 to +12) after r-hCG. Peak insulin level during OGTT changed by +28% (+16 to +98). Overnight LH pulse frequency changed by -64% (-89 to -10) and LH mean by -74% (-89 to -17). Two subjects in the spironolactone group demonstrated luteal LH patterns despite serum progesterone concentrations < 0.7 ng/mL. In the metformin group, free T changed by +35% (-32 to +125) unstimulated, by 36% (-54 to +66) after ACTH, and by 21% (-41 to +105) after r-hCG. Peak insulin level during OGTT changed by -47% (-74 to +102). LH pulse frequency changed by +10% (-29 to +22) and LH mean by +1% (-2 to +74). To summarize findings to date, mean LH and LH pulse frequency decreased in all three subjects taking spironolactone, including marked reductions in two subjects who demonstrated luteal LH patterns. While free T levels decreased in some of these girls, this seems unlikely to account for such marked changes in LH secretion. And despite similar decreases in T and also decreases in peak insulin in some girls taking metformin, LH pulse frequency did not change markedly. LH pulse patterns in two girls taking spironolactone suggest a progesterone-like effect on LH pulsatility. Spironolactone can cause irregular uterine bleeding, and canrenone (the major metabolite of spironolactone) binds to uterine progesterone receptors competitively (Fernandez MD, Br J Clin Pharm 1983). However, to our knowledge, this is the first report of LH pulse changes in HA girls using spironolactone. Further studies are needed to confirm this finding. Presentation Date: Saturday, June 17, 2023

P38α MAPK is a gatekeeper of uterine progesterone responsiveness at peri-implantation via Ube3c-mediated PGR degradation

Estrogen and progesterone specify the establishment of uterine receptivity mainly through their respective nuclear receptors, ER and PR. PR is transcriptionally induced by estrogen-ER signaling in the endometrium, but how the protein homeostasis of PR in the endometrium is regulated remains elusive. Here, we demonstrated that the uterine-selective depletion of P38α derails normal uterine receptivity ascribed to the dramatic down-regulation of PR protein and disordered progesterone responsiveness in the uterine stromal compartment, leading to defective implantation and female infertility. Specifically, Ube3c, an HECT family E3 ubiquitin ligase, targets PR for polyubiquitination and thus proteasome degradation in the absence of P38α. Moreover, we discovered that P38α restrains the polyubiquitination activity of Ube3c toward PR by phosphorylating the Ube3c at serine741 . In summary, we provided genetic evidence for the regulation of PR protein stability in the endometrium by P38α and identified Ube3c, whose activity was modulated by P38α-mediated phosphorylation, as an E3 ubiquitin ligase for PR in the uterus.

RETRACTED: Big data medical system and analgesic effect of dezocine in alleviating uterine contractions in pregnant women based on embedded processor

A review of pregnancy and pharmacological treatment of uterine activity factors and uterine activity during childbirth or abortion is the subject of this review. Uterus during pregnancy is usually stationary. Prostaglandin (PG) are believed to be endogenous simulator uterine contractions. Internal P.G. relating to the start. Uterine progesterone is considered sensitive to other local uterine contraction regulator agents. Oxytocin alone cannot effectively stimulate the uterus until to stimulate the uterus. It binds to the receptor. Decidual promote the synthesis of PG. local. Natural PG, PGF2alpha and PGE2 rapidly stimulate uterine tone, resulting in regular and continuous administration after shrinkage. In some countries/regions in common PG., analog is Gemeprost, Carboprost and Sulproston. It is the uterus, instead of the gastrointestinal tract, other than the route through intravenous administration. Ant progestin act by the reaction of the myocardium into an organ or spontaneous activity. These drugs can terminate an early pregnancy. When used in conjunction with P.G., hypertonic saline and ethacridine second-trimester abortion have long been used as a drug and act by causing the release of P.G. degradation and decidua.

Effect of progesterone antagonist RU486 on uterine progesterone receptor mRNA expression,embryonic development and ovarian function during early pregnancy in pigs

Effect of progesterone antagonist RU486 on uterine progesterone receptor mRNA expression,embryonic development and ovarian function during early pregnancy in pigs

Factors Associated With Subchorionic Hematoma Formation in Pregnancies Achieved Via Assisted Reproductive Technologies

To determine if certain clinical and/or embryologic factors are independently associated with the increased prevalence of subchorionic hematoma (SCH) among pregnancies achieved via in vitro fertilization (IVF) with fresh embryo transfer (ET). Retrospective chart review. In this retrospective study, data were abstracted from 210 autologous oocyte IVF clinical pregnancies that resulted from fresh ET at a single fertility center from January 2012 through December 2016. Clinical and embryology laboratory variables were analyzed as possible factors associated with the presence or absence of SCH in IVF pregnancies via bivariate associations and multivariable logistic regression analyses. Independent variables included prior uterine surgery versus no uterine surgery, peak estradiol, and progesterone levels, day 3 (n = 92) versus day 5 (n = 118) ET, and assisted hatching versus no assisted hatching. Among the day 5 ET subgroup of 118 patients, 117 had data for the variables inner cell mass (ICM) grading and trophectoderm (TE) because one day 5 ET was at the morula stage. We found a significant bivariate association between TE grading and SCH, where cases with TE grade “A” were significantly less likely to have SCH compared with cases with grades “B” or “C.” This significant difference remained when adjusting for the other factors considered in a multivariable logistic regression model for the probability of SCH. The data analyzed here suggest that a less-advanced trophectoderm grade may be a potential factor that is associated with the presence of SCH in pregnancies achieved via IVF.

Dietary restriction in sheep: Uterine functionality in ewes with different body reserves during early gestation

The aim of this study was to characterize insulin, leptin and IGF-1 profiles after undernutrition in pregnant ewes with different initial body condition (iBCS) and to investigate embryo quality, uterine gene expression and presence and location of proteins during early gestation (day 5). Thirty-six Rasa Aragonesa ewes were divided into 2 groups with different BCS: BCS> 2.75 (high, H, n = 19) and BCS <2.25 (low, L, n = 17) and they were randomly assigned to two nutritional treatments: 1.5 maintenance (M) (control, C) or 0.5 (M) (undernourishment, U) times the daily maintenance requirements establishing four groups: high-iBCS control (HC, n = 9), high-iBCS undernourished (HU, n = 10), low-iBCS control (LC, n = 9) and low-iBCS undernourished (LU, n = 8). High-iBCS ewes presented higher concentration of IGF-1, reflecting a better metabolic status in these animals. There was a greater proportion of high-iBCS ewes presenting more than one CL (P < 0.05), and associated greater P4 plasma concentration, number of recovered embryo and a tendency for higher embryo viability rate (P = 0.13). In uterus, undernourished ewes tended to present lower P4 (P = 0.09) and higher E2 concentration (P = 0.10). Inmunostaining of uterine progesterone and estrogen receptors (PR and ERα) was not affected by iBCS and nutritional treatment. Ewes with low-iBCS tended to have more INSR mRNA, and undernourished ewes tended to have more IGFBP2 mRNA expression (P < 0.08). An interesting finding was that the uterine response to undernutrition was dependent on iBCS: a higher expression of GHR (P < 0.05) and a tendency in IGFBP5 (P = 0.09) mRNA was found in undernourished than control ewes but only in the high-iBCS group. In summary, the present study demonstrates that the endocrine response and the uterine gene expression to undernutrition depend on the initial body energy reserves (iBCS) and appears to be associated with a differential embryo quality.

Synthesis of 4-hetero-16α,17α-cyclohexanopregnanes and evaluation of their cytotoxicity against the HeLa cell line

The oxidation of the ring A of 16α,17α-cyclohexanoprogesterone gave 5-oxo-A-nor-3,5-secopregnan-3-oic acid. The subsequent ring A closure in the latter compound upon treatment with sodium acetate in Ac2O afforded 4-oxasteroid. The reaction with ammonium acetate in acetic acid produced 4-azasteroid. Antiproliferative activity of the resulting steroids against cervical cancer HeLa cells and the in vitro binding to the progesterone receptor were studied. The compounds cause a statistically significant decrease in viability of cervical cancer HeLa cells, having no effect on normal skin fibroblasts. The tested steroids show very low binding to the rat uterine progesterone receptor.

Uterine progesterone signaling is a target for metformin therapy in PCOS-like rats.

Impaired progesterone (P4) signaling is linked to endometrial dysfunction and infertility in women with polycystic ovary syndrome (PCOS). Here, we report for the first time that elevated expression of progesterone receptor (PGR) isoforms A and B parallels increased estrogen receptor (ER) expression in PCOS-like rat uteri. The aberrant PGR-targeted gene expression in PCOS-like rats before and after implantation overlaps with dysregulated expression of Fkbp52 and Ncoa2, two genes that contribute to the development of uterine P4 resistance. In vivo and in vitro studies of the effects of metformin on the regulation of the uterine P4 signaling pathway under PCOS conditions showed that metformin directly inhibits the expression of PGR and ER along with the regulation of several genes that are targeted dependently or independently of PGR-mediated uterine implantation. Functionally, metformin treatment corrected the abnormal expression of cell-specific PGR and ER and some PGR-target genes in PCOS-like rats with implantation. Additionally, we documented how metformin contributes to the regulation of the PGR-associated MAPK/ERK/p38 signaling pathway in the PCOS-like rat uterus. Our data provide novel insights into how metformin therapy regulates uterine P4 signaling molecules under PCOS conditions.

Polycomb subunit BMI1 determines uterine progesterone responsiveness essential for normal embryo implantation.

Natural and synthetic progestogens have been commonly used to prevent recurrent pregnancy loss in women with inadequate progesterone secretion or reduced progesterone sensitivity. However, the clinical efficacy of progesterone and its analogs for maintaining pregnancy is variable. Additionally, the underlying cause of impaired endometrial progesterone responsiveness during early pregnancy remains unknown. Here, we demonstrated that uterine-selective depletion of BMI1, a key component of the polycomb repressive complex-1 (PRC1), hampers uterine progesterone responsiveness and derails normal uterine receptivity, resulting in implantation failure in mice. We further uncovered genetic and biochemical evidence that BMI1 interacts with the progesterone receptor (PR) and the E3 ligase E6AP in a polycomb complex-independent manner and regulates the PR ubiquitination that is essential for normal progesterone responsiveness. A close association of aberrantly low endometrial BMI1 expression with restrained PR responsiveness in women who had previously had a miscarriage indicated that the role of BMI1 in endometrial PR function is conserved in mice and in humans. In addition to uncovering a potential regulatory mechanism of BMI1 that ensures normal endometrial progesterone responsiveness during early pregnancy, our findings have the potential to help clarify the underlying causes of spontaneous pregnancy loss in women.

Immunosuppression with tacrolimus improved implantation and rescued expression of uterine progesterone receptor and its co-regulators FKBP52 and PIASy at nidation in the obese and diabetic mice: Comparative studies with metformin

Diabesity is often associated with subfertility and recurrent miscarriages. Evidence links systemic and local uterine cytotoxicity to the pathogenesis of implantation failure (IF) in diabetes. Immunosuppression with tacrolimus improved pregnancy outcomes in obese and diabetic mice and repeated IF in women with elevated Th1/Th2 blood cell ratios. However the mode of action of tacrolimus in protecting against IF and the molecular mechanisms associated with recurrent miscarriages in the obese and diabetic subjects are yet to be elucidated. Here we administered tacrolimus (FK506) (0.1 mg/kg) for four consecutive weeks to the NONcNZO10/LtJ mice, a model of human PCOS, chronically fed with 60% kCal fat for 16 consecutive weeks to simulate human obesity-associated T2DM. Compared to those immunosuppressed with tacrolimus and their normative controls, high-fat fed (HFD) diabetic NONcNZO mice exhibited higher rates of peri- and post-implantation resorption and had aberrant expression of uterine IFNγ and progesterone receptor (PGR) and its immunophilin co-chaperone FKBP52 at nidation. Immature uterodomes and lack of activation of uterine STAT3 and NFκB at implantation were characteristics of IF in the HFD-dNONcNZO dams also low in the deciduogenic factors IL11 and GM-CSF. Therapeutic interventions with tacrolimus or metformin normalized the expression of decidual IFNγ, PGR and FKBP52, increased co-localization of protein inhibitor of activated STATy (PIASy) to PGR and resulted in the upregulation of uterine IL11and LIF. Rescued phosphorylation of STAT3 and NFκBp65 and uterodome maturation at nidation defined implantation success in treated dams. To our knowledge this is the first report to show that the impact of HFD on the hemochorial implantation is at least in part mediated through disruption of PGR signaling at nidation and that immunosuppression with tacrolimus or treatment with metformin restores PGR-mediated influences during implantation in the obese and diabetic subjects.

Effects of dexamethasone on progesterone and estrogen profiles and uterine progesterone receptor localization during pregnancy in Sahel goat in Semi-Arid region

BackgroundDespite the widespread use of dexamethasone in veterinary and human medicine, it is reported to cause some severe pregnancy related side effects like abortion in some animals. The mechanism of the response is not clear but seems to be related to interspecies and/or breed difference in response which may involve alterations in the concentrations of some reproductive hormones.MethodsTwenty Sahel goats comprising 18 does and 2 bucks were used for this study. Pregnancies were achieved by natural mating after synchronization. Repeated dexamethasone injections were given at 0.25 mg/kg body weight. Blood samples were collected biweekly for hormonal assay. Uterine biopsies were harvested at days 28 and day 78 of gestation through caesarean section for immunohistochemical analysis using 3 pregnant does randomly selected from each group at each instant. Data were expressed as Means ± Standard Deviations and analyzed using statistical soft ware package, GraphPad Instant, version 3.0 (2003) and progesterone receptor (PR) were scored semi-quantitatively.ResultsDexamethasone treatments had no significant (p > 0.05) effect on progesterone and estrogen concentrations in pregnant Sahel goats but up regulated PR from 2+ to 3+ in second trimester.ConclusionAs dexamethasone adverse effect on placenta is an established fact, the lack of effect on progesterone level in this study may be due to the fact that unlike other species whose progesterone production during pregnancy is placenta – dependent, in goats is corpus luteum - dependent. Consequently dexamethasone adverse effect on placenta reported in literatures did not influence progesterone levels during pregnancy in Sahel goat. The up regulation of progesterone receptor (PR) in Sahel goat gravid uterus is a beneficial effects and that dexamethasone can safely be used in corpus luteum – dependent progesterone secreting pregnant animal species like Sahel goat and camel. Therefore source of progesterone secretions during pregnancy should be considered in clinical application of dexamethasone in pregnancy.

A Gata2-Dependent Transcription Network Regulates Uterine Progesterone Responsiveness and Endometrial Function

Altered progesterone responsiveness leads to female infertility and cancer, but underlying mechanisms remain unclear. Mice with uterine-specific ablation of GATA binding protein 2 (Gata2) are infertile, showing failures in embryo implantation, endometrial decidualization, and uninhibited estrogen signaling. Gata2 deficiency results in reduced progesterone receptor (PGR) expression and attenuated progesterone signaling, as evidenced by genome-wide expression profiling and chromatin immunoprecipitation. GATA2 not only occupies at and promotes expression of the Pgr gene but also regulates downstream progesterone responsive genes in conjunction with the PGR. Additionally, Gata2 knockout uteriexhibit abnormal luminal epithelia with ectopic TRP63 expressing squamous cells and a cancer-related molecular profile in a progesterone-independent manner. Lastly, we found a conserved GATA2-PGR regulatory network in both human and mice based on gene signature and path analyses using gene expression profiles of human endometrial tissues. In conclusion, uterine Gata2 regulates a key regulatory network of gene expression for progesterone signaling at the early pregnancy stage.

Effects of Intrauterine Devices in Mares: A Histomorphological and Immunohistochemical Evaluation of the Endometrium.

Oestrous suppression by intrauterine devices (IUDs) is caused by prolongation of luteal function, but the biological mechanism is unknown. The aim of the study was to investigate mechanisms which could explain the action of IUDs. Thirty mares were age-matched and either inseminated (AI, n = 15) or fitted with an IUD (IUD, n = 15) and subsequently divided into four groups: AI-P, pregnant (n = 8); AI-N, non-pregnant (n = 7); IUD-P, prolonged luteal phase (n = 7); and IUD-N, normal luteal phase (n = 8). The median ages were 5.5 and 7 years in AI-P and IUD-P groups and 14 and 11 years in AI-N and IUD-N groups, respectively. On Day 15 after ovulation, an endometrial biopsy was obtained to study histomorphological and immunohistochemical expression patterns of uterine proteins (uteroferrin, UF; uterocalin, UC; uteroglobin, UG), oestrogen and progesterone receptors (ER, PR), proliferation marker Ki-67 and content of inflammatory cells. Expression of UF was higher in IUD mares; the difference between pregnant and IUD-P mares was significant. Mares exhibiting a prolonged luteal phase (AI-P, IUD-P) showed only mild angiosclerosis and lower expression of both ER and PR than mares with a normal luteal phase (AI-N, IUD-N). No significant differences were detected in the numbers of inflammatory cells, with the exception of macrophages, which were more numerous in AI-P than AI-N mares. Although inflammatory cells were not detected in IUD mares, increased UF levels may indicate chronic inflammation. Young age and normality of the endometrial blood vessels may improve the efficacy of IUDs.

Neonatal Progesterone Programs Adult Uterine Responses to Progesterone and Susceptibility to Uterine Dysfunction.

In this report, we investigated the consequences of neonatal progesterone exposure on adult rat uterine function. Female pups were subcutaneously injected with vehicle or progesterone from postnatal days 3 to 9. Early progesterone exposure affected endometrial gland biogenesis, puberty, decidualization, and fertility. Because decidualization and pregnancy success are directly linked to progesterone action on the uterus, we investigated the responsiveness of the adult uterus to progesterone. We first identified progesterone-dependent uterine gene expression using RNA sequencing and quantitative RT-PCR in Holtzman Sprague-Dawley rats and progesterone-resistant Brown Norway rats. The impact of neonatal progesterone treatment on adult uterine progesterone responsiveness was next investigated using quantitative RT-PCR. Progesterone resistance affected the spectrum and total number of progesterone-responsive genes and the magnitude of uterine responses for a subset of progesterone targets. Several progesterone-responsive genes in adult uterus exhibited significantly dampened responses in neonatally progesterone-treated females compared with those of vehicle-treated controls, whereas other progesterone-responsive transcripts did not differ between female rats exposed to vehicle or progesterone as neonates. The organizational actions of progesterone on the uterus were dependent on signaling through the progesterone receptor but not estrogen receptor 1. To summarize, neonatal progesterone exposure leads to disturbances in endometrial gland biogenesis, progesterone resistance, and uterine dysfunction. Neonatal progesterone effectively programs adult uterine responsiveness to progesterone.

Effects of Ido1 on mouse decidualization

Indoleamine 2,3-dioxygenase 1 (Ido1) is a rate-limiting enzyme which converts the essential amino acid tryptophan to kynurenine. The aim of this study was to investigate the expression and regulation of Ido1 in mouse uterus during decidualization. The results showed that Ido1 mRNA expression gradually increased from day 1 to 4 of pregnancy and reached the peak level on day 4. On days 5-8 of pregnancy, a low level of Ido1 expression was observed in the uteri. Simultaneously, Ido1 mRNA was also lowly expressed in the decidualized uterus and the stromal cells treated with 8-Br-cAMP. Under in vitro decidualization, the expression of Ido1 mRNA gradually declined. Further studies found that overexpression of Ido1 can inhibit the expression of decidualization marker genes PRL, IGFBP1 and Dtprp under in vitro decidualization while inhibition of Ido1 with L-1-MT can induce the expression of these marker genes. Ido1 can prevent uterine stromal cells proliferation and enhance the expression of the Bax gene and increase the Bax/Bcl2 ratio under in vitro decidualization. Additionally, Ido1 can also modulate the expression of the MMP2 gene. In the uterine stromal cells, estrogen and progesterone can stimulate the expression of Ido1. These data indicate that Ido1 may play an important role during mouse decidualization and may be regulated by estrogen and progesterone in the uterine stromal cells.

Progesterone receptor expression declines in the guinea pig uterus during functional progesterone withdrawal and in response to prostaglandins.

Progesterone withdrawal is essential for parturition, but the mechanism of this pivotal hormonal change is unclear in women and other mammals that give birth without a pre-labor drop in maternal progesterone levels. One possibility suggested by uterine tissue analyses and cell culture models is that progesterone receptor levels change at term decreasing the progesterone responsiveness of the myometrium, which causes progesterone withdrawal at the functional level and results in estrogen dominance enhancing uterine contractility. In this investigation we have explored whether receptor mediated functional progesterone withdrawal occurs during late pregnancy and labor in vivo. We have also determined whether prostaglandins that induce labor cause functional progesterone withdrawal by altering myometrial progesterone receptor expression. Pregnant guinea pigs were used, since this animal loses progesterone responsiveness at term and gives birth in the presence of high maternal progesterone level similarly to primates. We found that progesterone receptor mRNA and protein A and B expression decreased in the guinea pig uterus during the last third of gestation and in labor. Prostaglandin administration reduced while prostaglandin synthesis inhibitor treatment increased progesterone receptor A protein abundance. Estrogen receptor-1 protein levels remained unchanged during late gestation, in labor and after prostaglandin or prostaglandin synthesis inhibitor administration. Steroid receptor levels were higher in the non-pregnant than in the pregnant uterine horns. We conclude that the decreasing expression of both progesterone receptors A and B is a physiological mechanism of functional progesterone withdrawal in the guinea pig during late pregnancy and in labor. Further, prostaglandins administered exogenously or produced endogenously stimulate labor in part by suppressing uterine progesterone receptor A expression, which may cause functional progesterone withdrawal, promote estrogen dominance and foster myometrial contractions.

Effect of hCG application in three different moments of the estrous cycle on ovarian and uterine vascularization and serum progesterone concentration

The mare is a seasonal breeder and in most situations a monovulatory individual. Therefore, a limited number of cycles per season makes a high pregnancy rate per cycle a very important goal to be achieved, in mares carrying their own or recipient mares. The use of drugs during diestrus in order to improve conception rates in inseminated and recipient mares has been the focus of several research groups. Some studies using hCG found promising results regarding pregnancy rates and recipient uterine characteristics on the day of transfer (Fleury et al., Revista Brasileira de Reproducao Animal, 2007 Belo Horizonte, v.31, n.1, p.27-31whereas others have detected a negative effect, showing a decrease on pregnancy rate when hCG was used [McCue et al., J Eq Vet Sci 2012;32:415]. In addition, hCG has been shown to have an effect on uterine vascularization in swine [Ziecik et al., Endocrinology 1986;119:1159–63], rats [Hermsteiner et al., Eur J Physiol 1999;439:186–4] and humans [Janiaux et al., Human Reproduction 1992;7:1467– 73]. The objectives of the present study were to evaluate the effect of hCG administration on luteal and uterine vascularization and serum progesterone concentration. Treatment groups were: G1: (control) no hCG application; G2: 2500 IU of hCG to induce ovulation when a follicle greater than 35 mm and uterine edema were detected; G3: 2500 IU hCG on day 0; G4: 2500 IU hCG on day 5 post ovulation. Twelve mares were randomly assigned to each

Agonistic activity of ICI 182 780 on activation of GSK 3β/AKT pathway in the rat uterus during the estrous cycle

We examined the ability of ICI 182,780 (ICI) to block uterine cell proliferation via protein kinase b/AKT pathway in the uterus of the rat during the estrous cycle. Intact rats, with regular estrous cycles, received a subcutaneous (s.c.) injection of either vehicle or ICI at 08:00h on the day of proestrus or at 00:00h on the day of estrus and sacrificed at 13:00h of metaestrus. Estradiol (E2) and progesterone (P4) plasma levels were measured by radioimmunoassay. Both ICI treatments, induced a significant decrease (p<0.01) in uterine estrogen receptor alpha (ERα) content, had no effect on uterine progesterone receptor (PR) protein expression and caused marked nuclear localization of cyclin D1, in both luminal and glandular uterine epithelium, as compared to vehicle-treated animals. Furthermore, we detected that ICI treatment induced glycogen synthase kinase (Gsk3-β) Ser 9 phosphorylation, which correlates with cyclin D1 nuclear localization. However, some differences were observed between the two different time schedules of administration. We observed that the administration of ICI at 08:00h on proestrus day produced a 15% inhibition of luminal epithelial cell proliferation, reduced uterine wet weight by 21% and caused reduction of Akt phosphorylation at Ser 473 as compared to vehicle-treated animals, whereas ICI treatment at 00:00h on estrus day had no effect on these parameters. The overall results indicate that ICI may exert agonistic and antagonistic effects on uterine cell proliferation through differential activation of the Akt pathway depending on the administration period during the estrous cycle, and indicates that the mechanism of cell proliferation during the physiological conditions of the estrous cycle, is under a different and more complex regulation than in the ovariectomized +E2 animal model.

The Natural Estrogenic Compound Diarylheptanoid (D3): In Vitro Mechanisms of Action and in Vivo Uterine Responses via Estrogen Receptor α

Background: Diarylheptanoid (D3) isolated from the medicinal plant, Curcuma comosa, has estrogenic activity.Objective: We aimed to elucidate the mechanism(s) of D3 action and compare it with that of 17β-estradiol (E2) using both in vitro and in vivo uterine models.Methods: We used human uterine (Ishikawa) cells to determine the estrogenic action of D3 on the activation and nuclear translocation of estrogen receptor α (ERα). In addition, we further characterized the uterine response to D3 treatment in vivo.Results: D3 activated an estrogen responsive element (ERE) luciferase reporter through ERα, and molecular modeling suggested that D3 could be accommodated in the ERα binding pocket. Using modified ERα to assay ligand-dependent nuclear translocation, we observed D3-dependent ERα interaction and translocation. In mouse uteri, early- and late-phase estrogen-regulated gene responses were increased in D3-treated ovariectomized wild-type animals, in a manner similar to that of E2; no response was seen in ERα knockout animals. We observed a divergence in estrogen responses after D3 treatment: D3 induced robust DNA synthesis in uterine epithelial cells, linked to an increase in cell-cycle–related genes; however, no increase in uterine weight was observed 24 hr after treatment. D3 also affected uterine progesterone receptor expression patterns similar to E2. When D3 and E2 were administered together, we observed no additive or antagonistic effects of D3 on E2. Our findings suggest that D3 is a weak estrogenic agonist compound.Conclusion: D3 is a weakly acting phytoestrogen that mimics the mitogenic responses produced by E2 in an ERα-dependent manner, but it is unable to increase uterine weight or enhance or antagonize the effects of estrogen.