Estradiol Pretreatment Research Articles

Effect of estradiol pretreatment on antagonist ICSI cycles outcome: A Randomized controlled trial

Effect of estradiol pretreatment on antagonist ICSI cycles outcome: A Randomized controlled trial

The use of combined hormonal contraceptive for in-vitro fertilization cycle priming is not associated with decreased pregnancy rate in frozen embryo transfer cycles: a cohort study.

The objectives of this study are to evaluate the cycle outcomes from IVF treatment preceded by oral contraceptive pills (OCP) priming compared to estradiol pretreatment and to determine if there is a role for OCP priming for those undergoing frozen embryo transfers. The study took place at a university-affiliated fertility center in Canada. The study included in-vitro fertilization (IVF) antagonist cycles from Jan 2016 to Jun 2019. Those with protocol deviation or treatment cancellation were excluded. There were 2237 cycles by 1958 patients; 27% of cycles utilized OCP priming. The average age in the OCP group was 34 years old compared to 36.5 in the estradiol group (P<0.01). AMH was reported in 43% of patients and was 3.7ng/mL in the OCP group versus 2.2 ng/mL in the estradiol group (P<0.01). The number of oocytes (15.2 vs. 12.5) and number of blastocysts (4.6 vs. 3.3) were higher in the OCP group (P all <0.01). After adjusting for age and AMH with linear regression for the 978 cycles with recorded AMH (24% with OCP prime), a significantly higher number of oocytes (13.8 vs. 11.9, P=0.002) was still noted in the OCP group. There were 866 euploid embryo transfer cycles (28% with OCP prime). There were no significant differences in implantation (77% vs. 76%) or ongoing pregnancy rates (56% vs. 54%) between those who had a frozen embryo transfer after OCP primed compared to estradiol primed stimulation cycles (P all >0.6). There were no differences in pregnancy outcomes from euploid frozen blastocyst transfers after OCP primed antagonist cycles compared to estradiol pretreatment. In fact, the use of OCP pretreatment was associated with increased oocyte yield, keeping in mind demographic differences with the OCP pretreatment group being younger with higher anti-Müllerian hormone and a higher prevalence of PCOS. Thus, OCP priming should still be considered in specific populations, such as those with oligo-ovulation or adequate ovarian reserve.

Editorial Expression of Concern: A comparative study of luteal estradiol pre-treatment in GnRH antagonist protocols and in micro dose flare protocols for poor-responding patients.

Editorial Expression of Concern: A comparative study of luteal estradiol pre-treatment in GnRH antagonist protocols and in micro dose flare protocols for poor-responding patients.

O-134 Pretreatment with luteal estradiol for programming antagonist cycles compared to no pretreatment in advanced age women treated with corifollitropin alfa: a randomized controlled trial

Abstract Study question Does luteal estradiol pretreatment improve the number of oocytes retrieved in women aged 38 to 43 years treated in antagonist protocol with corifollitropin alfa? Summary answer Programming antagonist cycles with luteal estradiol did not increase the number of retrieved oocytes in advanced age women, however it was effective for programming. What is known already Previous studies showed that programming IVF cycles with estradiol pretreatment is a valuable tool for the organization of IVF centers and patients. However, variable effects of estradiol pretreatment were observed on the number of retrieved oocytes: no difference in normal responders, improved yield in oocyte donors and conflicting results in poor responders but no improvement in those fulfilling the bologna criteria. In advanced age women, recruitable follicles tends to decrease in number and to be more heterogeneous in size but it remains unclear if estradiol pretreatment could yield more oocytes through its negative feed-back effect on FSH intercycle rise. Study design, size, duration This non-blinded randomized controlled trial was conducted between 2016 and 2022. Participants were 324 women aged 38 to 43 years who requested IVF treatment. The primary endpoint was the comparison of the total number of retrieved oocytes between pretreated (P) and no pretreated (NP) patients. Secondary endpoints were duration and total dosage of recombinant FSH, cancellation rate, total number of metaphase II oocytes and obtained embryos, fresh transfer live birth rate (LBR) and cumulative LBR. Participants/materials, setting, methods This multicentric study (6 centers) enrolled women with regular cycles, weight &amp;gt;50 kg and BMI &amp;lt;32, IVF rank 1-2. According to computerized randomization, micronized estradiol 2mg twice a day was started on day (D) 20-24 continued until Wednesday beyond the onset of menses followed by administration of corifollitropin alfa on Friday i.e. stimulation (S)1 or from D1-3 of a natural cycle in unpretreated patients. GnRH antagonist was started at S6 and additional rFSH at S8. Main results and the role of chance Basal characteristics were similar in estradiol P (n = 147; number (mean [SD]) of treatment days 9.8[2.6]) and NP patients (n = 144), both displaying however a wide range of AMH levels (0.3 to 11.6 ng/ml) for advanced age patients. The cancellation rate showed a trend to be lower in P group (11 vs 19 %, p = 0.11). The mean number of retrieved oocytes was lower in P compared to NP patients (8.4[6.1] vs 9.1[6], respectively). The treatment difference was -0.7[-2.1 ;0.8] p = 0.03 one tailed test . No significant differences were observed in the number of MII oocytes (7[5.5] vs 7.3[5.2], p = 0.72) and the number of obtained embryos (5[4.6] vs 5.2[4.2], p = 0.60) between the two groups. Oocytes retrieval was more often on working days in P patients (91.9 vs 74.2 %, p &amp;lt; 0.001). However, the duration of stimulation was significantly longer (11.7[1.7] vs 10.8[1.8] days, p &amp;lt; 0.001) and the extra rFSH dosage in addition to corifollitropin alfa was significantly higher (1040[548] vs 778[504] IU, p &amp;lt; 0.001) in P than NP patients. The LBR after fresh transfer in P patients (16.2%[16/99]) was not significantly different from that in NP patients (18.5%[17/92]), p = 0.82, nor the cumulative LBR per patients 19.1 % vs 26.4 %, p = 0.16 respectively. Limitations, reasons for caution Our stimulated women older than 38 years obtained a wide range of collected oocytes (0 to 29) suggesting very different stages of ovarian aging in both groups. Estradiol pretreatment is more susceptible to increase oocyte yield at the stage of ovarian aging characterized by asynchrony of a reduced follicular cohort Wider implications of the findings Programming antagonist cycles with luteal estradiol pretreatment is effective in advanced age women to better schedule oocyte retrievals on working days. However, the potential benefit on the number of collected oocytes remains to be demonstrated in a more selected population displaying the characteristics of Poseïdon groups 3 and 4. Trial registration number ClinicalTrials.gov NCT02884245

The Estrous Cycle Influences the Effects of Fatty Acid Amide Hydrolase and Monoacylglycerol Lipase Inhibition in the Anxiety-Like Behavior in Rats.

Background: Sex differences in the response to the anxiety-related effects of cannabinoid drugs have been reported, with females being more sensitive than males. Evidence suggests that, according to sex and estrous cycle phase (ECP), the content of the endocannabinoids (eCBs) N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG) varies in brain areas involved in the anxiety-like behavior. Methods: Considering the lack of studies evaluating sex and ECP differences in the eCB system in anxiety, using URB597, a fatty acid amide hydrolase inhibitor, or MJN110, a monoacylglycerol lipase inhibitor, we explored the effects of increasing AEA or 2-AG levels, respectively, in cycling and ovariectomized (OVX) female adult Wistar rats, as well as males, subjected to the elevated plus maze. Results: The administration of URB597 (0.1 or 0.3mg/kg; intraperitoneally) either increased or reduced the percentage of open arms time (%OAT) and open arms entries (%OAE), being anxiolytic in diestrus and anxiogenic in estrus. No effects were observed in proestrus or when all ECPs were analyzed together. Both doses produced anxiolytic-like effects in males. In OVX females, the anxiolytic-like effect of URB597 0.1 was associated with low levels of estradiol, whereas the anxiogenic-like effect of URB597 0.3 was spared by estradiol pretreatment. The systemic administration of MJN110 3.0 mg/kg reduced the risk assessment behavior (RAB), suggesting an anxiolytic-like effect independent of the ECP. When considering the ECP, MJN110 3.0 increased the %OAT and reduced the RAB, being anxiolytic in estrus and diestrus. No effects were observed in proestrus. Both doses of MJN110 were anxiogenic in males. In OVX females, the anxiolytic-like effect of MJN110 was dependent on low estradiol levels. Conclusion: Together, our findings support the evidence that females react differently to the effects of cannabinoids in the anxiety-like behavior; in addition, AEA and 2-AG modulation elicits anxiety-like responses that are closely influenced by hormone levels, mainly estradiol.

Ovarian hormones influence immune response to liver ischemia-reperfusion.

Liver injury occurs after ischemia and reperfusion (IR), as seen in transplant settings. Sex hormones have been implicated in many pathophysiological mechanisms in females and this could lead to liver protection under inflammatory reperfusion conditions where an excessive immune response occurs. Despite such assumptions, this fact needs to be further investigated. To address this, female and male C57BL/6J mice (8-12 weeks old) were studied. Bilateral ovariectomy (OVX) was performed in females to decrease estradiol levels. IR was performed, and after two weeks, all animals underwent a sham control operation or IR with euthanasia at the following time points after reperfusion: 6, 12, 24, and 48 h. IR triggered an inflammatory process in the liver with recruitment of neutrophils into the parenchyma of male mice. The female sham mice were protected against liver IR presenting no alteration of aminotransferase (ALT) levels compared to males. OVX caused loss of protection, increasing hepatic injury as represented by increased ALT levels and myeloperoxidase (MPO) activity. Female sham mice showed increased Akt phosphorylation and activation, while males showed reduced Akt activation. Estradiol pretreatment recovered ALT levels after IR injury, which was associated with decreased liver injury.

Estradiol pretreatment in GnRH antagonist protocol for IVF/ICSI treatment.

We conducted a systematic review and meta-analysis of all published data to determine the impact of estradiol pretreatment on reproductive outcomes and ovary stimulation characteristics for in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment with gonadotropin-releasing hormone (GnRH) antagonist protocol. MEDLINE, EMBASE, Cochrane Library, Web of Science, and China National Knowledge Infrastructure were searched, and any randomized controlled trials associated with estradiol pretreatment in GnRH antagonist protocol were included. Seven studies (1,236 patients) were included in the present study. The pooled data from the meta-analysis demonstrated no significant difference in ongoing pregnancy rate (odds ratio (OR): 0.92 (95% CI: 0.69-1.21; P = 0.53) and live birth rate OR: 0.98 (95% CI: 0.74-1.30; P = 0.90) between patients with and those without estradiol pretreatment in GnRH antagonist protocol. Duration of gonadotropin exposure, gonadotropin consumption, and the number of cumulus-oocyte complexes were not significantly different between groups. Luteal estradiol pretreatment in IVF/ICSI cycles with GnRH antagonist protocol in normal ovary responding population does not affect the reproductive outcomes. It is an encouraging option to facilitate cycle scheduling in GnRH antagonist protocol, for luteal estradiol pretreatment does not increase the duration of gonadotropin exposure or gonadotropin consumption.

P-359 Effect of estradiol pretreatment on antagonist ICSI cycles outcome

Abstract Study question Does estrogen pretreatment in antagonist ICSI cycles improves the outcome? Summary answer Pretreatment with estrogen in antagonist cycles reduced the days of stimulation, the number of hMG ampoules and enhanced the implantation rate. What is known already It has been previously reported that, programming of antagonist cycles with E2 only, started in the luteal phase and continued beyond the menses till the first day of stimulation, yielded similar results as the long agonist protocol. E2 pre-treatment in the luteal phase has an inhibiting role on follicular growth through its negative feedback on the FSH increase during the luteal follicular transition phase. This effect stops as soon as E2 administration is terminated. Study design, size, duration This was a prospective randomized controlled trial performed in a private IVF centers from June 2020 to February 2021. One hundred and fourteen infertile couples undergoing intracytoplasmic sperm injection embryo transfer cycles (ICSI-ET) were included. Participants/materials, setting, methods Group A includes 57 patients were pretreated with a dose of 4 mg estradiol valerate (progynova 2 mg; Bayer) once daily starting 10days before expected menses. Ovarian stimulation was started one day after the last estradiol dose, in a dose ranging from 225 to 375 IU of hMG. While in group B , 57 patients received stimulation in a dose of 225 to 375 IU of hMG starting on cycle day 2 without estradiol pretreatment. Main results and the role of chance The daily dose of hMG was significantly lower in The study group (P = 0.048), the stimulation days were significantly higher in the control group (P = 0.049), the total number of hMG ampoules was significantly higher in the control group (P = 0.041), and the implantation rate was higher in the study group (P = 0.045) , also the pregnancy rate (positive pregnancy test) was higher in the study group (p = 0.044) but there was no significant statistical difference detected as regards the clinical pregnancy rate between both groups (P = 0.180) , the serum estradiol on day of hCG ( p = 0.055), serum progesterone level on hCG day (P = 0.71) and the endometrial thickness (p = 0.780) . Also there is no significant statistical difference between the two groups as regarding number of follicles on day of hCG. (P = 0.803), the number of mature oocytes (P = 0.703) and no significant difference in the number of good quality embryos (p = 0.532) and the ratio of mature oocytes to number of follicles on day of hCG (P = 0.835), with no significant statistical difference between both groups. Limitations, reasons for caution The limitation of this study is the small number of patients as we included only 114 patients. Wider implications of the findings Luteal estradiol in antagonist cycles improved the outcomes of ICSI procedure by reducing the number of gonadotropin ampoules used for COH and reduced duration of stimulation, also the implantation rate is improved by luteal estradiol administration. Trial registration number NCT05197374

Abstract 5375: Precision run-on sequencing (PRO-seq) analysis of a treatment time course in ER+ breast cancer cell lines reveals the transcriptional changes underlying response to complete estrogen receptor antagonist (CERAN) OP-1250

Abstract OP-1250 is an orally-bioavailable complete estrogen receptor antagonist (CERAN) previously shown to shrink wild-type and Y537S mutant estrogen receptor-positive (ER+) tumors in multiple preclinical xenograft models. To better understand the effects of OP-1250 treatment on ER+ breast cancer cells, we used precision run-on sequencing (PRO-seq) to profile the direct transcriptional effects of OP-1250 in two commonly used breast cancer cell lines, MCF7 and CAMA-1. PRO-seq detects nascent RNA, and thus can detect changes at shorter timescales than traditional RNA-seq methods. We conducted PRO-seq 15 minutes, 1 hour, 6 hours and 24 hours after administration of OP-1250, estradiol, fulvestrant and tamoxifen to compare the effects of these compounds across the two cell lines. OP-1250 was administered in the absence of estradiol and after estradiol pretreatment to generate a detailed profile of the time course of its activity. We identified genes that display early transcriptional changes in response to the compounds tested, many of which have been previously identified as estrogen response genes. At later time points we observed transcriptional changes consistent with modulation of pathways involved in cell cycle progression. We show that OP-1250 treatment reverses the estradiol-induced transcriptional changes associated with estrogen receptor activation and chronicle the time course of these changes. Finally, we show greater similarity in the transcriptional changes induced by CERANs OP-1250 and fulvestrant compared to tamoxifen, as well as cell line-specific differences in estrogen response and response to anti-estrogen treatment. These data provide additional insights into the mechanisms of OP-1250 action on ER+ cell lines and patient tumors. OP-1250 is currently in a Phase I/II clinical trial for the treatment of ER+ breast cancer. Citation Format: Alison D. Parisian, Caitlin Miller, Fabian Ortega, Leslie Hodges-Gallagher, Susanna Barratt, Joey Azofeifa, Peter J. Kushner, David Kulp, Cyrus L. Harmon. Precision run-on sequencing (PRO-seq) analysis of a treatment time course in ER+ breast cancer cell lines reveals the transcriptional changes underlying response to complete estrogen receptor antagonist (CERAN) OP-1250 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5375.

Ovariectomy Affects Acute Pancreatitis in Mice.

Serum estradiol levels in severe acute injury are correlated with in hospital mortality. In acute pancreatitis, serum estradiol levels are strong predictors of disease severity. Studies of whether changes in estradiol levels play a causative role in acute pancreatitis severity are limited. The ovariectomized mouse model has been used to study the effects of estradiol in health and disease. We assessed whether the ovariectomized mouse model could be used to assess the effects of estradiol on pancreatitis severity. C57BL/6 mice with their ovaries removed were used to simulate low circulating estradiol conditions. Ovariectomized mice were treated with six hourly injections of cerulein to induce mild acute pancreatitis and compared to ovariectomized mice pre-treated with subcutaneous estradiol injections. Findings suggest ovariectomized model is a problematic preparation to study pancreatitis. At baseline, ovariectomy leads to prominent acinar cell ultrastructure changes as well as changes in other select morphologic and biomarkers of pancreatitis. In addition, ovariectomy changed select acute pancreatitis responses that were only partially rescued by estradiol pre-treatment. These findings suggest that the ovariectomized mouse as a model of estradiol depletion should be used with caution in pancreatic studies. Future studies should explore whether derangements in other female hormones produced by the ovaries can lead to changes in pancreatic studies.

Transcriptome analysis of the hypothalamus and pituitary of turkey hens with low and high egg production

BackgroundHigh egg producing hens (HEPH) show increased hypothalamic and pituitary gene expression related to hypothalamo-pituitary-gonadal (HPG) axis stimulation as well as increased in vitro responsiveness to gonadotropin releasing hormone (GnRH) stimulation in the pituitary when compared to low egg producing hens (LEPH). Transcriptome analysis was performed on hypothalamus and pituitary samples from LEPH and HEPH to identify novel regulators of HPG axis function.ResultsIn the hypothalamus and pituitary, 4644 differentially expressed genes (DEGs) were identified between LEPH and HEPH, with 2021 genes up-regulated in LEPH and 2623 genes up-regulated in HEPH. In LEPH, up-regulated genes showed enrichment of the hypothalamo-pituitary-thyroid (HPT) axis. Beta-estradiol was identified as an upstream regulator regardless of tissue. When LEPH and HEPH samples were compared, beta-estradiol was activated in HEPH in 3 of the 4 comparisons, which correlated to the number of beta-estradiol target genes up-regulated in HEPH. In in vitro pituitary cell cultures from LEPH and HEPH, thyroid hormone pretreatment negatively impacted gonadotropin subunit mRNA levels in cells from both LEPH and HEPH, with the effect being more prominent in HEPH cells. Additionally, the effect of estradiol pretreatment on gonadotropin subunit mRNA levels in HEPH cells was negative, whereas estradiol pretreatment increased gonadotropin subunit mRNA levels in LEPH cells.ConclusionsUp-regulation of the HPT axis in LEPH and upstream beta-estradiol activation in HEPH may play a role in regulating HPG axis function, and ultimately ovulation rates. Thyroid hormone and estradiol pretreatment impacted gonadotropin mRNA levels following GnRH stimulation, with the inhibitory effects of thyroid hormone more detrimental in HEPH and estradiol stimulatory effects more prominent in LEPH. Responsiveness to thyroid hormone and estradiol may be due to desensitization to thyroid hormone and estradiol in LEPH and HEPH, respectively, due to up-regulation of the HPT axis in LEPH and of the HPG axis in HEPH. Further studies will be necessary to identify possible target gene desensitization mechanisms and elicit the regulatory role of the HPT axis and beta-estradiol on ovulation rates in turkey hens.

High expression of estrogen receptor alpha and aromatase in glial tumor cells is associated with gender-independent survival benefits in glioblastoma patients

IntroductionGlioblastoma multiforme (GBM) is a highly malignant glial tumor, affecting men more often than women. The reason for this gender-specific predominance remains unclear, raising the question whether these effects are subject to hormonal control. The purpose of this study was to examine the expression of estrogen receptor alpha (ERα) and aromatase in human GBM tissue samples in relation to patient survival and furthermore to investigate the effect of standard chemotherapy in combination with estradiol treatment on glioblastoma tumor cell lines in vitro.Methods60 tissue samples (31 male, 29 female) of GBM patients were analysed with immunohistochemistry for ERα and aromatase for survival analyses. The cell lines LN18 and LN229 were treated with 17β-estradiol (E2) in different dosing regimens and the cell viability was measured with MTT assay. After estradiol pre-treatment Temozolomide was added and tested again.ResultsHigh expression of ERα and aromatase in the GBM tissue samples was associated with significantly longer survival times of GBM patients, regardless of gender and body-mass-index. The treatment with high concentrations of estradiol resulted in lower tumor cell viability, compared to control. The cells significantly showed a stronger sensitivity against Temozolomid (TMZ) after estradiol pre-treatment.ConclusionERα-expression of glial tumour cells seems to play an important prognostic role as a biomarker in GBM, as well as the expression of the enzyme Aromatase. The combined treatment of GBM with standard chemotherapy and estradiol may be beneficial to patient’s survival.

Effects of estradiol pretreatment during follicular period on outcome of in vitro fertilization and embryo transfer treatment for poor ovarian responder with high FSH level

TO observe the effects of estradiol pretreatment during follicular period on outcomes of in vitro fertilization and embryo transfer (IVF-ET) treatment for poor ovrian responder(POR) with high FSH level. A prospective randomized controlled study. A total of 323 POR with high level who have undergoing IVF-ET treatment were randomly divided into the pretreatment group(n=163) and non-pretreatment group(n=160) acording to whether the estradial pretreatmen (oral administration with 17- β estradiol for 4mg-6mg/d at the second day to the fourth day of menstrual cycle) were conducted before super ovulation induction.General information and indices relevant to the outcome of IVF-ET treatment of two groups were compared. In the pretreatment group, serum follicle-stimulating hormone (FSH)(13.77/14.17IU/ml, p=0.53)levels on the second day of menstruation(D2) and the fifth day(D5) were statistically significant；The D2 serum FSH in the non-pretreatment group was also statistically significant compared to that of the FSH in D5 (13.94/8.85，P=0.00).However,there was no statistical significance in comparing D2 FSH (13.98/13.94IU，P=0.51) and D5 FSH (8.79/8.85IU，P=0.45) values between the two groups.The differences of age (37.93/37.56years,P=0.5),BMI (22.13/21.80Kg/m2,P=0.16),AMH (0.89/0.91ng/ml,P=0.57),basal antral follicle count ( AFC ) (3.57/3.59,P=0.23),the number of retrieved oocytes (2.68/2.25,P=0.70) ,unovulated rate(15.34/13.13,P=0.569), endometrial thickness (10.49/10.49mm，P=0.41),the number of embryos transferred (1.60/1.63,P=0.12),transplant cancellation rate(28.21/31.90%,P=0.474) and clinical pregnancy rate (13.30/11.70%,P=0.10) were not statistically significant between the two groups. Estradiol pretreatment in follicular phase at POR patients with high FSH level did not increase the number of MII eggs rate and clinic pregnancy rate.On the contrary, an increase in the Gn dosage and extended treatment period can impose unnecessary burden on a patient, both financially and mentally. To some extent, the level of FSH only reflects the function of the ovary. Therefore, reducing the blood FSH level cannot increase the number of eggs nor improve the clinical pregnancy outcome.

Luteal estradiol pretreatment of poor and normal responders during GnRH antagonist protocol

Luteal estradiol pretreatment (LEP) to IVF protocols designed to improve follicle synchronization and retrieval of mature oocytes. We conducted a retrospective study including women undergoing IVF program who were given a course of 4 mg oral estradiol-17β daily from day 20 of the same cycle until day 1 of their next cycle before starting an antagonist protocol, forming LEP-group but control-group started on day 3 a stimulation without pretreatment. A total is divided into 2 groups (poor (group 1, n = 148) and normal responders (group 2, n = 244)). Our findings show for group 1 a significant decrease in cancelation rate (3% vs 14%) and a significant improvement in clinical outcomes (clinical pregnancy per transfer and live birth rate respectively: 47% and 44% vs 12% and 11%). For group 2, this pretreatment could increase significantly the maturation rate (77% vs 68%). The rate of frozen embryos was improved in both groups: (group 1: 11% vs 2% and group 2: 53% vs 41%). LEP increases the frozen embryos rate whatever the nature of the ovarian response, but especially for normal responders it coordinates follicular recruitment increasing the maturation rate. In the case of poor responders, it affects positively clinical outcomes decreasing the canceled cycles.

Chronic 17β-estradiol pretreatment has pronociceptive effect on behavioral and morphological changes induced by orofacial formalin in ovariectomized rats.

BackgroundThe prevalence of craniofacial pain disorders show sexual dimorphism with generally more common appearance in women suggesting the influence of estradiol, but the exact cause remains unknown. The common point in the pathogenesis of these disorders is the activation of trigeminal system. One of the animal experimental models of trigeminal activation is the orofacial formalin test, in which we investigated the effect of chronic 17β-estradiol pretreatment on the trigeminal pain-related behavior and activation of trigeminal second-order neurons at the level of spinal trigeminal nucleus pars caudalis (TNC).MethodsFemale Sprague Dawley rats were ovariectomized and silicone capsules were implanted subcutaneously containing cholesterol in the OVX group and 17β-estradiol and cholesterol in 1:1 ratio in the OVX+E2 group. We determined 17β-estradiol levels in serum after the implantation of capsules. Three weeks after operation, 50 µL of physiological saline or 1.5% of formalin solution was injected subcutaneously into the right whisker pad of rats. The time spent on rubbing directed to the injected area and c-Fos immunoreactivity in TNC was measured as the formalin-induced pain-related behavior, and as the marker of pain-related neuronal activation, respectively.ResultsThe chronic 17β-estradiol pretreatment mimics the plasma levels of estrogen occurring in the proestrus phase and significantly increased the formalin-induced pain-related behavior and neuronal activation in TNC.ConclusionOur results demonstrate that the chronic 17β-estradiol treatment has strong pronociceptive effect on orofacial formalin-induced inflammatory pain suggesting modulatory action of estradiol on head pain through estrogen receptors, which are present in the trigeminal system.

Progesterone administration does not acutely alter LH pulse secretion in the mid-follicular phase in women.

It remains unclear how rapidly progesterone suppresses luteinizing hormone (LH) pulse frequency in women. Previous studies suggested that progesterone markedly increases LH pulse amplitude but does not slow LH pulse frequency within 10 h in estradiol‐pretreated women studied during the late follicular phase. However, this experimental paradigm may be a model of preovulatory physiology, and progesterone may have different effects at other times of the cycle. We studied regularly cycling, nonobese women without hyperandrogenism to assess the acute effect of progesterone during the midfollicular phase and in the absence of estradiol pretreatment. The study involved two admissions in separate cycles (cycle days 5–9). For each admission, either oral micronized progesterone (100 mg) or placebo was administered at 0900 h in a randomized, double‐blind fashion. Frequent blood sampling was performed between 0900 and 1900 h to define 10‐h LH pulsatility. Treatment crossover (placebo exchanged for progesterone and vice versa) occurred in a subsequent cycle. After an interim futility analysis, the study was halted after 7 women completed study. Mean progesterone concentrations after placebo and progesterone administration were 0.5 ± 0.1 (mean ± SD) and 6.7 ± 1.6 ng/mL, respectively. Compared to placebo, progesterone was not associated with a significant difference in 10‐h LH pulse frequency (0.79 ± 0.35 vs. 0.77 ± 0.28 pulses/h, P = 1.0) or amplitude (3.6 ± 2.8 vs. 4.3 ± 2.8 IU/L, P = 0.30). This study suggests that LH pulse frequency is not rapidly influenced by progesterone administration during the midfollicular phase.

S146 The modulation of CSD in animals

Objectives Cortical spreading depression (CSD) is thought to be the electrophysiological correlate of migrainous aura, thus its modulation might revail further details of migraine pathomechanism. We summarize scientific data from previous animal experiments regarding CSD modulation. Methods The characteristics of KCl induced CSD waves were examined after various pretreatments (migraine prophylactic drugs, kinurenines, gonadal hormones) in rats. Results Lamotrigine was able to supress CSD-s, while valproic acid decreased only its propagation velocity. In other experiments kynurenic acid, an endogenous glutamate antagonist proved to be effective in the reduction of rat CSD waves. Both progesteron and estradiol pretreatment increased the CSD frequency. Discussion Some of the migraine prophylactic drugs are able to modulate CSD, but others not, which suggests that these medications act at different levels of migraine genesis. The suppressing effect of kynurenines is possibly related to their anti-glutamatergic action. Interestingly female gonadal steroids have a marked effect on CSD generation, which might be linked to the strong sexual dimorphism of migraine headache.

Secretion of Gonadotropins in Response to a Novel Kiss-1 Receptor Agonist, RF9 in the Mare: Modulation by Estradiol-17β and Half-Life of RF9 in the Peripheral Circulation

Three experiments were conducted to investigate the effects of the kisspeptin receptor agonist, 1-adamantanecarbonyl-RF-NH2 (RF9) on the secretion of gonadotropins, the role of estradiol-17β in modulating this response, and the metabolic half-life of RF9 in the mare. During the luteal phase of the estrous cycle (experiment 1), light horse mares were treated with sequential I.V. injections of RF9 (0.2 and 0.4 mg/kg) within a 1-hour interval to determine effects on coincident secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Dose-dependent increases (P < .001) in concentrations of both FSH and LH in response to RF9 were observed. In experiment 2, the effect of estradiol-17β (estradiol) pretreatment on responsiveness to RF9 was examined in winter anovulatory mares. Mares received a single intramuscular injection of 5-mg estradiol or corn oil followed by a bolus injection of RF9 18 hours later. Estradiol pretreatment increased (P < .05) peak concentrations of LH in response to RF9. The half-life of RF9 in the circulation of mares following peripheral administration was determined in experiment 3 using liquid chromatography/mass spectrometry. Intravenously injected RF9 was rapidly cleared from the mare's circulatory system, exhibiting a half-life of approximately 40 minutes. Data indicate that RF9 action is likely mediated via the endogenous release of GnRH and controls secretion of both FSH and LH. This effect is modulated by estradiol, putatively by enhanced responsiveness of the pituitary to GnRH and/or upregulation of Kiss-1 receptor in GnRH neurons. Use of RF9 as a pharmacologic agent in the mare may be limited by its short half-life.

Effect of 17β estradiol pretreatment on inflammatory responses during propofol-induced apoptosis in hippocampal nerve cells of developing rats

Objective To evaluate the effect of 17β estradiol pretreatment on inflammatory responses during propofol-induced apoptosis in hippocampal nerve cells of developing rats. Methods Thirty-nine pathogen-free healthy male Sprague-Dawley rats, aged 7 days, weighing 11-18 g, were divided into 3 groups (n=13 each) using a random number table: fat emulsion group (group F), propofol group (group P) and propofol plus 17β estradiol group (group P+ E). Propofol 75 mg/kg was intraperitoneally injected once every 24 h for 7 consecutive days in group P, and the equal volume of fat emulsion was given instead in group F. In group P+ E, 17β estradiol 600 μg/kg was subcutaneously injected, and 30 min later propofol 75 mg/kg was intraperitoneally injected once every 24 h for 7 consecutive days.The rats were sacrificed at 24 h after the last injection, the brains were removed and hippocampi were isolated for determination of activated caspase-3 expression (using Western blot) and interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) contents (by enzyme-linked immunosorbent assay). Results The levels of activated caspase-3, IL-1β and TNF-α in hippocampi were significantly higher in group P than in group F (P<0.05). The levels of activated caspase-3, IL-1β and TNF-α in hippocampi were significantly lower in group P+ E than in group P (P<0.05). Conclusion The mechanism by which 17β estradiol pretreatment inhibits propofol-induced apoptosis in hippocampal nerve cells is related to inhibition of inflammatory responses of developing rats. Key words: Propofol; Estradiol; Apoptosis; Hippocampus; Inflammation

Anovulatory Patients Demonstrate a Sharp Decline in LH Levels upon GnRH Antagonist Administration during IVF Cycles.

To evaluate the decrease in luteinizing hormone (LH) levels following gonadotropin-releasing hormone (GnRH) antagonist administration in in vitro fertilization (IVF) cycles, data were retrospectively collected from 305 consecutive IVF or intracytoplasmic sperm injection (ICSI) cycles of patients who underwent ovarian stimulation with gonadotropins and were treated with GnRH antagonist for the prevention of premature luteinization. We compared the percent change in LH concentration from stimulation start to that observed before ovulation triggering in patients with or without anovulation. Anovulatory patients were younger, with higher body mass index (BMI), and demonstrated higher ovarian reserve parameters as compared to ovulatory patients. The decline in LH concentration was almost two-fold greater in anovulatory versus ovulatory patients. Numbers of oocytes, fertilizations, cleavage stage embryos, and transferred embryos were similar; however, implantation rates were higher in anovulatory versus ovulatory patients. Older patients (age ≥39) showed a smaller decline in LH levels as compared to younger ones (age <39) and exhibited poor IVF outcomes. There is a wide range of pituitary responses to GnRH antagonists. Anovulatory patients are more susceptible to GnRH antagonists and therefore demonstrate over-suppression of the pituitary. Older patients demonstrate a reduced pituitary response to GnRH antagonists than younger ones. Cycle scheduling with estradiol pretreatment did not influence LH decline, nor IVF treatment outcomes.