Progesterone can block the preovulatory gonadotropin-releasing hormone/luteinising hormone surge in the ewe by a direct inhibitory action on oestradiol-responsive cells within the hypothalamus

Neuroendocrine control of gonadotropin-releasing hormone: Pulsatile and surge modes of secretion

The concept that different systems control episodic and surge secretion of gonadotropin-releasing hormone (GnRH) was well established by the time that GnRH was identified and formed the framework for studies of the physiological roles of GnRH, and later kisspeptin. Here, we focus on recent studies identifying the neural mechanisms underlying these two modes of secretion, with an emphasis on their core components. There is now compelling data that kisspeptin neurons in the arcuate nucleus that also contain neurokinin B (NKB) and dynorphin (i.e., KNDy cells) and their projections to GnRH dendrons constitute the GnRH pulse generator in mice and rats. There is also strong evidence for a similar role for KNDy neurons in sheep and goats, and weaker data in monkeys and humans. However, whether KNDy neurons act on GnRH dendrons and/or GnRH soma and dendrites that are found in the mediobasal hypothalamus (MBH) of these species remains unclear. The core components of the GnRH/luteinising hormone surge consist of an endocrine signal that initiates the process and a neural trigger that drives GnRH secretion during the surge. In all spontaneous ovulators, the core endocrine signal is a rise in estradiol secretion from the maturing follicle(s), with the site of estrogen positive feedback being the rostral periventricular kisspeptin neurons in rodents and neurons in the MBH of sheep and primates. There is considerable species variations in the neural trigger, with three major classes. First, in reflex ovulators, this trigger is initiated by coitus and carried to the hypothalamus by neural or vascular pathways. Second, in rodents, there is a time of day signal that originates in the suprachiasmatic nucleus and activates rostral periventricular kisspeptin neurons and GnRH soma and dendrites. Finally, in sheep nitric oxide-producing neurons in the ventromedial nucleus, KNDy neurons and rostral kisspeptin neurons all appear to participate in driving GnRH release during the surge.

Epithelial-to-mesenchymal transition contributes to the downregulation of progesterone receptor expression in endometriosis lesions

Endometriosis is a common, estrogen-dependent disease, in which endometrial tissue grows in the peritoneal cavity. These lesions often express low levels of progesterone receptors (PR), which potentially play an important role in the insufficient response to progestin treatment. Here, we uncover an interconnection between the downregulated PR expression and the epithelial-to-mesenchymal transition (EMT) in endometriotic lesions. The majority of ectopic epithelial glands (93.1 %, n = 67/72) display heterogeneous states of EMT by immunohistochemistry staining. Interestingly, low PR expression associated with high N-cadherin expression, a hallmark of EMT. In order to gain mechanistic insights, we performed in vitro functional assays with the endometriotic epithelial cell lines EM'osis and 12Z. TGF-β-induced EMT, marked by elevations of CDH2 and SNAI1/2, led to a significant downregulation of PR gene expression in both cell lines. In contrast, silencing of SNAI1 in EM'osis and of SNAI1 plus SNAI2 in 12Z elevated PR gene expression significantly. We found that not only in vitro, but also in the epithelial component of endometriotic lesions strong expression of SNAI1/2 concurred with weak expression of PR. In summary, these results suggested the negative correlation association of the heterogeneous states of EMT and suppressed PR expression in endometriotic lesions. Our functional assays indicate that EMT contributes to the downregulation of PR expression via the upregulation of EMT-TFs, like SNAI1 and SNAI2, which may ultimately lead to progesterone resistance.

Endocrinological effects of social exclusion and inclusion: Experimental evidence for adaptive regulation of female fecundity

When current conditions are probabilistically less suitable for successful reproduction than future conditions, females may prevent or delay reproduction until conditions improve. Throughout human evolution, social support was likely crucial to female reproductive success. Women may thus have evolved fertility regulation systems sensitive to cues from the social environment. However, current understanding of how psychological phenomena might affect female ovarian function is limited. In this study, we examined whether cues of reduced social support-social ostracism-impact women's hormone production. Following an in-lab group bonding task, women were randomly assigned to a social exclusion (n = 88) or social inclusion (n = 81) condition. After social exclusion, women with low background levels of social support experienced a decrease in estradiol relative to progesterone. In contrast, socially-included women with low background social support experienced an increase in estradiol relative to progesterone. Hormonal changes in both conditions occurred specifically when women were in their mid-to-late follicular phase, when baseline estradiol is high and progesterone is low. Follow-up analyses revealed that these changes were primarily driven by changes in progesterone, consistent with existing evidence for disruption of ovarian function following adrenal release of follicular-phase progesterone. Results offer support for a potential mechanism by which fecundity could respond adaptively to the loss or lack of social support.

Fixed Gonadotropin-Releasing Hormone Antagonist Protocol Versus Flexible Progestin-Primed Ovarian Stimulation Protocol in Patients With Asynchronous Follicular Development During Controlled Ovulation Stimulation: A Retrospective Study

Protocols utilizing gonadotropin-releasing hormone (GnRH) antagonists have emerged as mainstream procedures for ovarian stimulation; however, GnRH increases the risk for periodic cancellation of embryos. Therefore, this study aimed to compare the pregnancy outcomes of a fixed GnRH antagonist protocol and a flexible progestin-primed ovarian stimulation (fPPOS) protocol in patients with asynchronous follicular development during controlled ovulation stimulation and to explore the feasibility of converting patients undergoing a fixed GnRH antagonist protocol to an fPPOS protocol. This was the first retrospective study exploring the fPPOS protocol in patients with asynchronous follicular development, and it was conducted in a public reproductive medicine center from January to December 2020. We included infertile women. All participants were scheduled to undergo administration of a GnRH antagonist on the fifth day of controlled ovulation stimulation. The study group included 129 women who were converted from the fixed GnRH antagonist protocol to the fPPOS protocol for their asynchronous follicular development, while the antagonist group consisted of 258 women (ratio 1:2) who proceeded with a fixed GnRH antagonist protocol. On the second or third day of the menstrual period, 100-300 IU/day gonadotropin injections were administered. For patients who were converted to the fPPOS protocol, medroxyprogesterone acetate tablets at 10 mg/day were started on the fifth day of stimulation or when only one leading follicle reached 14 mm and the other follicles were ≤10 mm in diameter, whichever came first. The rates of embryo implantation, clinical pregnancy, and early pregnancy loss were obtained. The number of oocytes retrieved and the number of high-quality embryos in the antagonist group were significantly higher than those in the fPPOS group (P = 0.039 and P = 0.025, respectively). No significant differences in the rates of embryo implantation, clinical pregnancy, and early pregnancy loss were observed between the two groups. Our study found that in patients who were scheduled for administration of GnRH antagonists but presented with asynchronous follicular development on the fifth stimulation day, it was feasible to switch to the fPPOS protocol.

Comparison of the effects of Duphaston and Cetrotide on oocyte and embryo quality in women undergoing ICSI: A cross-sectional study

Background

Premature luteinizing hormone (LH) surge is one of the causes for assisted reproductive technology cycle cancellation, and it is needed to find novel approaches with improved efficacy and safety profile.

Objective

To compare the effects of Duphaston and Cetrotide on the prevention of premature LH surge and characteristics of retrieved follicles and embryos in women undergoing intracytoplasmic sperm injection.

Materials and Methods

In this retrospective cross-sectional study, 200 patients who were administrated recombinant follicle-stimulating hormone from the third day of menstruation cycle were included. When the follicular diameter reached above 13-14 mm, Cetrotide was prescribed in the control group, while in the case group, Duphaston was taken orally from the third day of cycle. The retrieved oocytes were fertilized in vitro by intracytoplasmic sperm. The level of hormones on the third day of menstruation and the characteristic of follicles, oocytes, and embryos were compared between the two groups.

Results

Duphaston successfully inhibits premature LH surge. There was no significant difference in the level of follicle-stimulating hormone, estradiol, and LH between the case and control groups (p > 0.05). However, results also showed that Duphaston causes more oocyte retrieval in comparison with Cetrotide (p = 0.04). Although, the number of follicles above 14 mm, mature oocyte, and the total number of viable embryos in the case group was slightly higher, it did not reach a significant difference compared with the control group (p > 0.05).

Conclusion

Duphaston could be used as an appropriate medication instead of gonadotropin-releasing hormone antagonists in women undergoing controlled ovarian hyperstimulation. Duphaston prescription not only prevents premature LH surge but also improves the number of retrieved oocytes.

Dydrogesterone-primed ovarian stimulation is an effective alternative to gonadotropin-releasing hormone antagonist protocol for freeze-all cycles in polycystic ovary syndrome

OBJECTIVE

To compare the effects of progestin-primed ovarian stimulation using dydrogesterone (DYD) and a gonadotropin-releasing hormone (GnRH) antagonist protocol on cycle characteristics and pregnancy rates in freeze-all cycles in patients with polycystic ovary syndrome (PCOS).

METHODS

Medical records of PCOS patients who underwent freeze-all in vitro fertilization cycles between April 2017 and April 2019 at the Novafertil in vitro fertilization Center were retrospectively evaluated. The primary outcome measure was the incidence of premature luteinizing hormone surge. Secondary outcome measures were the total number of mature oocytes retrieved, fertilization rate, clinical pregnancy rates and ongoing pregnancy rates.

RESULTS

A total of 525 patients were included in the study. DYD-primed ovarian stimulation and a GnRH antagonist protocol were applied in 258 and 267 patients, respectively. The baseline parameters were similar between the two groups. The numbers of mature and fertilized oocytes were similar in the cetrorelix (CET) group and DYD group (11.43 ± 3.48 vs. 11.29 ± 4.34, respectively, P = 0.692; and 8.98 ± 2.93 vs. 8.62 ± 3.67, respectively, P = 0.208). Premature luteinization was rare in both groups, and the difference between the groups was not statistically significant (2.9% vs. 1.5%, respectively, P = 0.268). There was no significant difference in clinical pregnancy rate of the first frozen embryo transfer cycle between the DYG group and the CET group (56% [120/214] vs. 55.6% [113/203], respectively, P = 0.283). There were no significant differences in biochemical pregnancy rates, implantation rates, miscarriage rates or ongoing pregnancy rates between the two groups (P > 0.05).

CONCLUSION

Dydrogesterone-primed ovarian stimulation seems to be an effective alternative to the GnRH antagonist protocol for freeze-all cycles in PCOS patients.

Role of kisspeptin neurons as a GnRH surge generator: Comparative aspects in rodents and non-rodent mammals

Ovulation is an essential phenomenon for reproduction in mammalian females along with follicular growth. It is well established that gonadal function is controlled by the neuroendocrine system called the hypothalamus-pituitary-gonadal (HPG) axis. Gonadotropin-releasing hormone (GnRH) neurons, localized in the hypothalamus, had been considered to be the head in governing the HPG axis for a long time until the discovery of kisspeptin. In females, induction of ovulation and folliculogenesis has been linked to a surge mode and pulse mode of GnRH releases, respectively. The mechanisms of how the two modes of GnRH are differently regulated had long remained elusive. The discovery of kisspeptin neurons, distributed in two hypothalamic nuclei, such as the arcuate nucleus in the caudal hypothalamus and preoptic area or the anteroventral periventricular nucleus in the rostral hypothalamic regions, and analyses of the detailed functions of kisspeptin neurons have led marked progress on the understanding of different mechanisms regulating GnRH surges (ovulation) and GnRH pulses (folliculogenesis). The present review will focus on the role of kisspeptin neurons as the GnRH surge generator, including the sexual differentiation of the surge generation system and factors that regulate the surge generator. Comparative aspects between mammalian species are especially focused on.

Ovarian response in oocyte donation cycles under LH suppression with GnRH antagonist or desogestrel progestin: retrospective and comparative study

Here are investigated the serum hormones in ovarian stimulation cycles of oocyte donors (OD), under endogenous luteinizing hormone (LH) suppression with GnRH antagonist (antGnRH) vs. desogestrel (DSG) (progesterone-primed [PP]). OD underwent ovarian stimulation with gonadotropins at a private, university-based, infertility center between January 2017 and March 2018. Endogenous LH peak was controlled with either daily injections of antGnRH or with daily oral 75 mcg DSG (PP) until triggering. LH and progesterone were measured at trigger and the following day. A total of 404 OD cycles were included. There were no differences in age (26.7 ± 4.9 vs. 27.1 ± 4.8 years), AMH (3.7 ± 2.1 vs. 4.1 ± 2.7 ng/ml), and body mass index (BMI) (22.4 ± 2.8 vs. 22.1 ± 3.0 kg/m²) between PP and antGnRH groups, respectively. On the day of trigger, progesterone was lower in PP compared to antGnRH (0.9 ± 0.7, vs. 1.5 ± 1.2 ng/ml, p < .001), whereas no significant differences existed in estradiol or LH. On the day after trigger, lower progesterone in PP vs. antGnRH (10.8 ± 6.0 vs. 13.4 ± 7.9 ng/ml, p=.002) was observed. No differences were observed in the number of retrieved oocytes or the clinical pregnancies among recipients. Our study shows that endocrine response to DSG differs significantly as compared to antGnRH use for the control of endogenous LH without apparent impact on number of retrieved oocytes or the clinical pregnancies among recipients.

Comparison of a novel flexible progestin primed ovarian stimulation protocol and the flexible gonadotropin-releasing hormone antagonist protocol for assisted reproductive technology

OBJECTIVE

To determine whether a flexible progestin primed ovarian stimulation (fPPOS) protocol is effective for preventing premature ovulation.

DESIGN

Retrospective cohort study.

SETTING

Private assisted reproduction center.

PATIENT(S)

Eighty-seven oocyte donors and 191 recipients of fresh oocytes.

INTERVENTION(S)

Each donor was stimulated with a flexible gonadotropin-releasing hormone (GnRH) antagonist protocol in one cycle and with the new fPPOS protocol in the other, within a period of 6 months. FSH was started on cycle day 2-3, and 0.25 mg/day GnRH antagonist or 10 mg/day medroxyprogesterone acetate (MPA) was started on stimulation day 7 or when the leading follicle reached 14 mm, whichever came first.

MAIN OUTCOME MEASURE(S)

Duration of stimulation, gonadotropin consumption, duration of GnRH antagonist or MPA administration, number of metaphase II oocytes, and pregnancy rates in fresh oocyte recipients.

RESULTS

Duration of stimulation was 11 (10-11) days in both groups. Total gonadotropin consumption was similar. Pituitary suppression was started on day 7 and lasted for 5 days in each group. There were no premature ovulations in any group. The fPPOS yielded a significantly higher number of cumulus oocyte complexes than GnRH antagonist cycles (33 [21-39] vs. 26 [18-36], respectively). Likewise, the fPPOS generated significantly more metaphase II oocytes than GnRH antagonist cycles (24 [17-34] vs. 21 [15-28], respectively). Recipients of fresh oocytes from fPPOS and GnRH antagonist cycles had similar cleavage, blastulation, implantation, and live birth/ongoing pregnancy rates (50% vs. 48.6%).

CONCLUSION(S)

FPPOS with MPA seems to be an effective choice for preventing premature ovulation in women undergoing ovarian stimulation without compromising oocyte quality.

Pilot Study to Evaluate the Association Between the Length of the Luteal Phase and Estrous Activity Detected by Automated Activity Monitoring in Dairy Cows

The ability of automated activity monitoring (AAM) systems to detect estrus is influenced by multiple variables. The luteal phase (LP) preceding estrus has been shown to be important for hormones release, and behavior during estrus in ruminants, but its impact on activity as measured by AAM systems has not been studied. The objective of this study was to investigate the impact of the length of the preceding LP on the intensity and duration of estrus as measured by AAM, and on the expression of estrogen receptor alpha (ERα) in the endometrium. A total of 60 cows between 46 and 53 days in milk were assigned to either a normal or a short length LP. Length of the LP was insured by the use of hormonal synchronization programs. Cows in both treatments were matched on parity, milk production, body condition score (BCS), and lameness score (assessed at enrolment). Expression of ERα receptors in the endometrium were evaluated by nuclear staining by immunohistochemistry of biopsies. Estrus was defined as the day on which the AAM system detected estrus. Cows that were not synchronized by the protocol or that were not detected in estrus by the AAM systems were excluded, which left 21 and 11 cows for analyses in the normal and short length LP, respectively. Peak activity index of estrus, duration of estrus, and expression of ERα were outcomes for multivariable linear regression models. Cows with short length LP tended to have lower peak activity at estrus, but there was no significant effect of treatment when BCS was accounted for. Cows with BCS ≤ 2.5 had less intense and shorter estrus than cows with BCS ≥ 2.75. There was no association between the length of the LP and the expression of ERα in the endometrium.

Gonadotropin-releasing hormone antagonist versus progestin for the prevention of premature luteinising hormone surges in poor responders undergoing in vitro fertilisation treatment: study protocol for a randomised controlled trial

BACKGROUND

Progress in vitrification techniques has allowed reproductive physicians to consider new strategies for using progestin as an alternative to a GnRH analogue to improve in vitro fertilisation (IVF). However, the role of progestin in blocking luteinising hormone (LH) surges and its potential in clinical practice are unclear, especially for poor responders. We designed a prospective randomised controlled trial (RCT) to compare the efficacy of a gonadotropin-releasing hormone (GnRH) antagonist and progestin in blocking LH surges and premature ovulation in poor responders.

METHODS/DESIGN

Poor responders who meet the Bologna criteria will be randomised to one of two stimulation regimens-gonadotropin-releasing hormone (GnRH) antagonist or progestin-primed ovarian stimulation (PPOS)-using a computer-generated random number. Fresh embryos were transferred in the GnRH antagonist group and frozen embryos were transferred in the PPOS group. The primary outcome is the incidence of premature LH surges. Secondary outcomes include the number of oocytes retrieved, the number of embryos available for transfer, implantation rates and clinical pregnancy. The sample size for this trial is estimated as 340 participants, with 170 participants in each group. The data analysis will be by intention to treat.

DISCUSSION

To our knowledge, this is the first RCT to examine the efficacy of administering progestin orally to block LH surges and premature ovulation compared with the GnRH antagonist protocols in poor responders undergoing IVF treatment.

TRIAL REGISTRATION

www.chictr.org.cn . ChiCTR-IPR-17010906 . Registered on 18 March 2017.

An extremely patient-friendly and efficient stimulation protocol for assisted reproductive technology in normal and high responders

BACKGROUND

The use of oral progestin has been shown to effectively prevent luteining hormone (LH) surge during ovarian stimulation with daily human menopausal gonadotropin injections. This study was aimed to investigate the efficacy of long-acting follicle stimulating hormone (long-acting FSH; corifollitropin alfa, Elonva®) use in progestin-primed ovarian stimulation for normal and high responders undergoing IVF/ICSI.

METHODS

This is a retrospective and proof-of-concept study. We developed an extremely patient-friendly protocol to be applied to forty-five normal or high responders, in which a single injection of corifollitropin alfa (Elonva®) was administered and medroxyprogesterone acetate (MPA) was taken orally every day from the day after Elonva injection to the day of trigger. Seven days after Elonva injection, folliculometry and hormone tests were performed, followed by short-acting daily FSH/LH injections, if needed, until the day before trigger. Duration of stimulation, number of injections and visits before trigger, incidence of premature LH surge, the number of oocytes retrieved, fertilization rate, cleavage rate, the rate of day 2 good embryos available, and cumulative ongoing pregnancy rate per retrieval were assessed.

RESULTS

The average age of the population was 34.7 years. Duration of stimulation was 9.4 days in average. Before trigger, only 3.6 injection shots and 1.4 visits were needed on average. There was no case of premature LH surge. Number of oocytes retrieved was 13.7, fertilization rate was 79.04%, cleavage rate was 91.11%, and day 2 good embryo rate was 64.34%, in average respectively. There was no case of ovarian hyperstimulation syndrome. The cumulative ongoing pregnancy rate per oocyte retrieval achieved a satisfactory level as 53.1%.

CONCLUSIONS

Our protocol consisting of long-acting FSH injection and oral MPA preventing LH surge reduces the number of injections and visits to an extreme and achieves a satisfactory reproductive outcome, and, therefore, is a really patient-friendly and effective approach to ovarian stimulation.

KNDy neurone activation prior to the LH surge of the ewe is disrupted by LPS

In the ewe, steroid hormones act on the hypothalamic arcuate nucleus (ARC) to initiate the GnRH/LH surge. Within the ARC, steroid signal transduction may be mediated by estrogen receptive dopamine-, β-endorphin- or neuropeptide Y (NPY)-expressing cells, as well as those co-localising kisspeptin, neurokinin B (NKB) and dynorphin (termed KNDy). We investigated the time during the follicular phase when these cells become activated (i.e., co-localise c-Fos) relative to the timing of the LH surge onset and may therefore be involved in the surge generating mechanism. Furthermore, we aimed to elucidate whether these activation patterns are altered after lipopolysaccharide (LPS) administration, which is known to inhibit the LH surge. Follicular phases of ewes were synchronised by progesterone withdrawal and blood samples were collected every 2 h. Hypothalamic tissue was retrieved at various times during the follicular phase with or without the administration of LPS (100 ng/kg). The percentage of activated dopamine cells decreased before the onset of sexual behaviour, whereas activation of β-endorphin decreased and NPY activation tended to increase during the LH surge. These patterns were not disturbed by LPS administration. Maximal co-expression of c-Fos in dynorphin immunoreactive neurons was observed earlier during the follicular phase, compared to kisspeptin and NKB, which were maximally activated during the surge. This indicates a distinct role for ARC dynorphin in the LH surge generation mechanism. Acute LPS decreased the percentage of activated dynorphin and kisspeptin immunoreactive cells. Thus, in the ovary-intact ewe, KNDy neurones are activated prior to the LH surge onset and this pattern is inhibited by the administration of LPS.

Prenatal Testosterone Treatment Leads to Changes in the Morphology of KNDy Neurons, Their Inputs, and Projections to GnRH Cells in Female Sheep

Prenatal testosterone (T)-treated ewes display a constellation of reproductive defects that closely mirror those seen in PCOS women, including altered hormonal feedback control of GnRH. Kisspeptin/neurokinin B/dynorphin (KNDy) neurons of the arcuate nucleus (ARC) play a key role in steroid feedback control of GnRH secretion, and prenatal T treatment in sheep causes an imbalance of KNDy peptide expression within the ARC. In the present study, we tested the hypothesis that prenatal T exposure, in addition to altering KNDy peptides, leads to changes in the morphology and synaptic inputs of this population, kisspeptin cells of the preoptic area (POA), and GnRH cells. Prenatal T treatment significantly increased the size of KNDy cell somas, whereas POA kisspeptin, GnRH, agouti-related peptide, and proopiomelanocortin neurons were each unchanged in size. Prenatal T treatment also significantly reduced the total number of synaptic inputs onto KNDy neurons and POA kisspeptin neurons; for KNDy neurons, the decrease was partly due to a decrease in KNDy-KNDy synapses, whereas KNDy inputs to POA kisspeptin cells were unaltered. Finally, prenatal T reduced the total number of inputs to GnRH cells in both the POA and medial basal hypothalamus, and this change was in part due to a decreased number of inputs from KNDy neurons. The hypertrophy of KNDy cells in prenatal T sheep resembles that seen in ARC kisspeptin cells of postmenopausal women, and together with changes in their synaptic inputs and projections to GnRH neurons, may contribute to defects in steroidal control of GnRH observed in this animal model.

Medroxyprogesterone acetate is an effective oral alternative for preventing premature luteinizing hormone surges in women undergoing controlled ovarian hyperstimulation for in vitro fertilization

OBJECTIVE

To investigate the use of medroxyprogesterone acetate (MPA) to prevent LH surge during controlled ovarian hyperstimulation (COH) and to compare cycle characteristics and pregnancy outcomes in subsequently frozen-thawed ET (FET) cycles.

DESIGN

A prospective controlled study.

SETTING

Tertiary-care academic medical center.

PATIENT(S)

Three hundred patients undergoing IVF/intracytoplasmic sperm injection treatment.

INTERVENTION(S)

In the study group, hMG and MPA were administered simultaneously beginning on cycle day 3. Ovulation was induced with a GnRH agonist or cotriggered by a GnRH agonist and hCG when dominant follicles matured. A short protocol was used in the control group. Viable embryos were cryopreserved for later transfer in both protocols.

MAIN OUTCOME MEASURE(S)

The primary outcome measure was the number of oocytes retrieved. Secondary outcomes included the number of mature oocytes, the incidence of premature LH surge, and clinical pregnancy outcomes from FETs.

RESULT(S)

The number of oocytes retrieved in the study group was similar to those in the controls (9.9 ± 6.7 vs. 9.0 ± 6.0), and higher doses of hMG were administered. In the study group, LH suppression persisted during ovarian stimulation, and the incidence of premature LH surge was 0.7% (1/150). No statistically significant differences were found in the clinical pregnancy rates (47.8% vs. 43.3%), implantation rates (31.9% vs. 27.7%), and live-birth rates (42.6% vs. 35.5%) in the study group and controls.

CONCLUSION(S)

The results show that MPA is an effective oral alternative for the prevention of premature LH surge in woman undergoing COH. This finding will help establish a new regimen for ovarian stimulation in combination with embryo cryopreservation.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR-ONRC-14004419.

Utrogestan as an effective oral alternative for preventing premature luteinizing hormone surges in women undergoing controlled ovarian hyperstimulation for in vitro fertilization

A major cause of cycle cancellation during controlled ovarian hyperstimulation (COH) in women undergoing in vitro fertilization (IVF) is the occurrence of premature luteinizing hormone (LH) surges. Steroidal preparations can modulate the secretion of gonadotropins (Gn); however, few studies using progesterone to inhibit the premature LH surges in COH have been published. The purpose of the study was to evaluate the oral delivery of progesterone soft capsules (Utrogestan) to prevent LH surges from the follicular phase and to compare cycle characteristics as well as to evaluate pregnancy outcomes in subsequent frozen-thawed embryo transfer (FET) cycles. A total of 374 patients were enrolled in this retrospective study, among which 187 patients were simultaneously administered Utrogestan and human menopausal gonadotrophin (hMG) from cycle day 3 until the trigger day. A short protocol including 187 controls with comparable age, body mass index (BMI), infertility duration, and antral follicle count was also used. GnRH agonist (0.1 mg) or hCG (3000 IU) was used for a trigger when the dominant follicles matured. Viable embryos were cryopreserved for later transfer in both groups. The primary outcome was the number of oocytes retrieved. The secondary outcomes included the number of mature oocytes, incidence of premature LH surge, and clinical pregnancy outcomes from FET cycles. Consistent LH suppression was achieved during COH, with a range of 0.07 to 8.9 IU/L, and no premature LH surge was detected. The number of oocytes retrieved in the Utrogestan and hMG protocol was comparable with that in the short protocol (10.92 ± 5.74 vs 10.6 ± 6.22, P > 0.05), and the dose of hMG was higher than that used in the short protocol (1884.22 ± 439.47 IU vs 1446.26 ± 550.48 IU, P < 0.05). No significant between-group difference was observed in the mature oocyte rate (88.88% vs 90.12%), cleavage rate (96.58% vs 96.58%), clinical pregnancy rate (54.27% vs 51.65%), or implantation rate (33.59% vs 34.02%). The study shows that Utrogestan is an effective oral alternative for preventing premature LH surges in women undergoing COH, which will help to establish a convenient user regimen in combination with FET.

Activation of cells containing estrogen receptor alpha or somatostatin in the medial preoptic area, arcuate nucleus, and ventromedial nucleus of intact ewes during the follicular phase, and alteration after lipopolysaccharide

Cells in the medial preoptic area (mPOA), arcuate nucleus (ARC), and ventromedial nucleus (VMN) that possess estrogen receptor alpha (ER alpha) mediate estradiol feedback to regulate endocrine and behavioral events during the estrous cycle. A percentage of ER alpha cells located in the ARC and VMN express somatostatin (SST) and are activated in response to estradiol. The aims of the present study were to investigate the location of c-Fos, a marker for activation, in cells containing ER alpha or SST at various times during the follicular phase and to determine whether lipopolysaccharide (LPS) administration, which leads to disruption of the luteinizing hormone (LH) surge, is accompanied by altered ER alpha and/or SST activation patterns. Follicular phases were synchronized with progesterone vaginal pessaries, and control animals were killed at 0, 16, 31, and 40 h (n = 4-6/group) after progesterone withdrawal (PW [time 0]). At 28 h, other animals received LPS (100 ng/kg) and were subsequently killed at 31 h or 40 h (n = 5/group). Hypothalamic sections were immunostained for c-Fos and ER alpha or SST. LH surges occurred only in control ewes with onset at 36.7 ± 1.3 h after PW; these animals had a marked increase in the percentage of ER alpha cells that colocalized c-Fos (%ER alpha/c-Fos) in the ARC and mPOA from 31 h after PW and throughout the LH surge. In the VMN, %ER alpha/c-Fos was higher in animals that expressed sexual behavior than in those that did not. SST cell activation in the ARC and VMN was greater during the LH surge than in other stages in the follicular phase. At 31 or 40 h after PW (i.e., 3 or 12 h after treatment, respectively), LPS decreased %ER alpha/c-Fos in the ARC and the mPOA, but there was no change in the VMN compared to that in controls. The %SST/c-Fos increased in the VMN at 31 h after PW (i.e., 3 h after LPS) with no change in the ARC compared to controls. These results indicate that there is a distinct temporal pattern of ER alpha cell activation in the hypothalamus during the follicular phase, which begins in the ARC and mPOA at least 6-7 h before the LH surge onset and extends to the VMN after the onset of sexual behavior and LH surge. Furthermore, during the surge, some of these ER alpha-activated cells may be SST-secreting cells. This pattern is markedly altered by LPS administered during the late follicular phase, indicating that the disruptive effects of this stressor are mediated by suppressing ER alpha cell activation at the level of the mPOA and ARC and enhancing SST cell activation in the VMN, leading to the attenuation of the LH surge.

Nimodipine, a calcium channel blocker, delays the spontaneous LH surge in women with regular menstrual cycles: a prospective pilot study

BACKGROUND

Currently GnRH analogue injections are used to prevent premature LH surges in women undergoing assisted reproductive technology. This was a pilot study to determine the safety and effectiveness of nimodipine, an oral calcium channel blocker, to delay the mid-cycle spontaneous LH surge in women with regular menstrual cycles.

METHODS

Eight women with regular menstrual cycles self-monitored three consecutive cycles for the day of an LH surge by daily urine assay. The first and third cycles were observatory. In the second cycle, subjects took nimodipine 60 mg by mouth three times daily for four days, starting two days prior to the expected LH surge day based on cycle one.

RESULTS

The LH surge day in cycle 2 (nimodipine) was significantly delayed in comparison to both observatory cycle 1 (15.5+/-3.4 vs 14.0+/-2.8 days; p=0.033) and cycle 3 (15.1+/-3.5 vs 13.1+/-2.4 days; p=0.044). There was no difference in the LH surge day between the two observatory cycles (13.4+/-2.4 vs 13.1+/-2.4 days; p=0.457). Three patients experienced a mild headache.

CONCLUSIONS

There was a statistically significant delay in the spontaneous LH surge day in the treatment cycle in comparison to both observatory cycles. Nimopidine should be further investigated as an oral alternative to delay a spontaneous LH surge.

Kisspeptin, c-Fos and CRFR type 2 expression in the preoptic area and mediobasal hypothalamus during the follicular phase of intact ewes, and alteration after LPS

Increasing estradiol concentrations during the late follicular phase stimulate sexual behavior and the GnRH/LH surge, and it is known that kisspeptin signaling is essential for the latter. Administration of LPS can block these events, but the mechanism involved is unclear. We examined brain tissue from intact ewes to determine: i) which regions are activated with respect to sexual behavior, the LH surge and LPS administration, ii) the location and activation pattern of kisspeptin cells in control and LPS treated animals, and iii) whether CRFR type 2 is involved in such disruptive mechanisms. Follicular phases were synchronized with progesterone vaginal pessaries and control animals were killed at 0 h, 16 h, 31 h or 40 h (n=4-6/group) after progesterone withdrawal (time zero). At 28 h, other animals received endotoxin (LPS; 100 ng/kg) and were subsequently killed at 31 h or 40 h (n=5/group). LH surges only occurred in control ewes, during which there was a marked increase in c-Fos expression within the ventromedial nucleus (VMN), arcuate nucleus (ARC), and medial preoptic area (mPOA), as well as an increase in the percentage of kisspeptin cells co-expressing c-Fos in the ARC and mPOA compared to animals sacrificed at all other times. Expression of c-Fos also increased in the bed nucleus of the stria terminalis (BNST) in animals just before the expected onset of sexual behavior. However, LPS treatment increased c-Fos expression within the VMN, ARC, mPOA and diagonal band of broca (dBb), along with CRFR type 2 immunoreactivity in the lower part of the ARC and median eminence (ME), compared to controls. Furthermore, the percentage of kisspeptin cells co-expressing c-Fos was lower in the ARC and mPOA. Thus, we hypothesize that in intact ewes, the BNST is involved in the initiation of sexual behavior while the VMN, ARC, and mPOA as well as kisspeptin cells located in the latter two areas are involved in estradiol positive feedback only during the LH surge. By contrast, disruption of sexual behavior and the LH surge after LPS involves cells located in the VMN, ARC, mPOA and dBb, as well as cells containing CRFR type 2 in the lower part of the ARC and ME, and is accompanied by inhibition of kisspeptin cell activation in both the ARC and mPOA.

Follicular dynamics, interval to ovulation and fertility after AI in short-term progesterone and PGF2α oestrous synchronization protocol in sheep

The study was aimed to assess the influence that short-term progesterone treatments have on follicular dynamics, oestrus and ovulation in sheep. The treatment was tested thereafter in a field trial to assess its fertility after AI with fresh semen. In a first experiment, 12 ewes without CL were grouped to receive a new (n = 6) or used CIDR (n = 6) for 7 days and blood samples were obtained to follow plasma progesterone profiles. In a second experiment, 39 cycling ewes were synchronized by a 7-day P4+PGF2α protocol using a new (n = 20) or a 7-day used CIDR (n = 19). Half of both groups received 400 IU eCG and half remained untreated as controls. Ultrasound ovarian examination and oestrous detection were used to compare follicular dynamics, oestrus and ovulation in both groups. In a third experiment, 288 ewes in 3 farms were synchronized by the short-term P4+PGF2α+eCG protocol and ewes were AI with fresh semen 24 h after oestrous detection. Lambing performance was used to test the fertility of the treatment. In Experiment 1, ewes with new inserts presented higher P4 concentration than ewes with used inserts throughout the sampling period (p < 0.05) and exhibited a P4 peak at days 1-2 of the treatment that was not observed in ewes with used inserts. In Experiment 2, ewes treated with new and used inserts show similar ovarian and behavioral traits (p > 0.10). However, ewes treated with eCG show shorter interval to oestrus (p = 0.004) and tend to have larger mature CL (p = 0.06). In Experiment 3, oestrous presentation and lambing performance after AI with fresh semen was considered normal compared to published results. Results suggest that the oestrous synchronization protocol based on P4+PGF2α allows little control of follicular dynamics without compromising fertility after AI with fresh semen provided that eCG is added at the end of the treatment.

Distribution of mRNAs encoding classical progestin receptor, progesterone membrane components 1 and 2, serpine mRNA binding protein 1, and progestin and ADIPOQ receptor family members 7 and 8 in rat forebrain

Several lines of evidence suggest the existence of multiple progestin receptors that may account for rapid and delayed effects of progesterone in the CNS. The delayed effects have been long attributed to activation of the classical progestin receptor (Pgr). Recent studies have discovered novel progestin signaling molecules that may be responsible for rapid effects. These include progesterone receptor membrane component 1 (Pgrmc1), Pgrmc2, progestin and adipoQ receptor 7 (Paqr7) and Paqr8. The functions of these molecules have been investigated extensively in non-neural, but not in neural tissues, partly because it is unclear which are expressed in the brain and where they are expressed. To address these issues, we compared the distributions of mRNAs encoding Pgr, Pgrmc1, Pgrmc2, Paqr7 and Paqr8 using in situ hybridization with radiolabeled oligodeoxynucleotidyl probes in forebrain tissues of estradiol-treated female rats. We also examined the distribution of serpine mRNA binding protein 1 (Serbp1), a putative binding partner of Pgrmc1. Analyses of adjacent brain sections showed that the highest expression of mRNAs encoding Pgr, Pgrmc1, Pgrmc2 and Serbp1 was detected in several hypothalamic nuclei important for female reproduction. In contrast, expression patterns of Paqr7 and Paqr8 were low and homogeneous in the hypothalamus, and more abundant in thalamic nuclei. The neuroanatomical distributions of these putative progestin signaling molecules suggest that Pgrmc1 and Pgrmc2 may play roles in neuroendocrine functions while Paqr7 and Paqr8 are more likely to regulate sensory and cognitive functions.

Progesterone receptor A (PRA) and PRB-independent effects of progesterone on gonadotropin-releasing hormone release

Progesterone's (P4) negative feedback actions in the female reproductive axis are exerted in part by suppression of hypothalamic GnRH release. Here we show that P4 can inhibit GnRH release by a mechanism independent of a nuclear P4 receptor (PR(A/B)). Injections of P4, but not vehicle, allopregnanolone, or dexamethasone, acutely suppressed LH levels in both wild-type and P4 receptor knockout ovariectomized mice; pituitary responsiveness to GnRH was retained during P4 treatment, indicating a hypothalamic action. Superfusion of GnRH-producing GT1-7 cells with medium containing 10(-7) m P4 produced a rapid reduction in GnRH release. Incubation with P4 (10(-9) to 10(-7) M) inhibited forskolin-stimulated cAMP accumulation; cotreatment with pertussis toxin prevented this effect. Treatment of GT1-7 cell membranes with P4 caused activation of an inhibitory G protein (G(i)), as shown by immunoprecipitation with a G(i) antibody of most of the increase in membrane-bound [(35)S]GTPgamma-S. Saturation binding analyses demonstrated the presence of a high affinity (K(d) 5.85 nM), limited capacity (Bmax 62.2 nM) binding site for P4. RT-PCR analysis revealed the presence of mRNAs encoding both isoforms of the membrane P4 receptors, mPRalpha and mPRbeta. Western blotting, immunocytochemistry, and flow cytometry experiments similarly revealed expression of mPR proteins in the plasma membranes of GT1-7 cells. Treatment with mPRalpha siRNA attenuated specific P4 binding to GT1-7 cell membranes and reversed the P4 inhibition of cAMP accumulation. Taken together, our results suggest that negative feedback actions of P4 include rapid PR(A/B)-independent effects on GnRH release that may in part be mediated by mPRs.

Non-genomic actions of progesterone and estrogens in regulating reproductive events in domestic animals

It has been established that nuclear receptors mediate the action of estrogens and progestins in regulating gene expression in the hypothalamic-hypophyseal-gonadal axis of domestic animals during various reproductive states. Results of recent in vitro studies suggest that estradiol-17beta and progesterone can act non-genomically to affect signal transduction responses in target cells by binding to receptors in the plasma membrane. The genomic action of steroids is generally detectable in hours to days whereas non-genomic responses of cells occur in seconds to minutes. The nature of the plasma membrane receptors for estrogens and progesterone has been explored but has not been conclusively established for all cell types studied. In the ewe, estradiol-17beta or estradiol-bovine serum albumin conjugate has been shown by in vitro and in vivo approaches to act non-genomically to suppress luteinizing hormone secretion by gonadotropes and stimulate production of nitric oxide by uterine arterial endothelial cells. Progesterone has been shown to inhibit oxytocin (OT) binding to its receptor in isolated ovine endometrial plasma membranes. This non-genomic action of progesterone blocks OT activation of the phosphoinositide cascade and production of prostaglandin F(2alpha) by ovine and bovine endometrium. The acrosome reaction of caprine and porcine spermatozoa is activated by the non-genomic action of progesterone. Further research is required to define the biological significances of the non-genomic actions of estrogens and progestins.

Differential Estradiol Requirement for the Induction of Estrus Behavior and the Luteinizing Hormone Surge in Two Breeds of Sheep1

For a better understanding of the mechanisms that lead to the preovulatory GnRH/LH surge and estrus behavior, the minimum estradiol (E) requirements (dose and duration) to induce each of these events were determined and compared between two breeds of ewes having either single (Ile de France) or multiple (Romanov) ovulations. The ewes were initially studied during a natural estrus cycle, and were then ovariectomized and run through successive artificial estrus cycles. For these artificial cycles the duration and amplitude of the follucular phase E increase were manipulated by E implants. Under all conditions, the onset of estrus behavior was similar in the two breeds, although its duration was longer in Romanov ewes. While a moderate E signal (6 cm for 12 h) induced an LH surge in 10/10 Ile de France ewes, a larger E signal (12 cm for 12 h) was minimally effective in Romanov ewes (4/10). Additional studies revealed that a small E signal (3 cm for 6 h) induced full estrus behavior in all Romanov ewes but was completely ineffective in Ile de France animals (0/10). Higher doses and mostly longer durations of the E signal (12 cm for 24 h) were required to induce a surge in all the Romanov ewes. These results demonstrate a clear difference in the E requirement for the induction of estrus behavior and the LH surge between breeds of ewes that have different ovulation rates. These data provide compelling evidence that, in one breed, the neuronal systems that regulate both events require different estrogen signals.

Nongenomic action of progesterone inhibits oxytocin-induced phosphoinositide hydrolysis and prostaglandin F2alpha secretion in the ovine endometrium

Experiments were conducted to characterize the nongenomic effects of progesterone (P4) on binding of oxytocin (OT) to its receptor and signal transduction in the ovine endometrium. The dose-response relationship of P4 to OT binding was examined. Membranes from endometrial tissue of ovariectomized hormone-treated ewes were preincubated in the presence of P4 for 1 h followed by OT receptor analysis. P4 interfered with the binding of OT in a dose-dependent manner. Endometrium was then recovered from cyclic ewes and divided into explants. Treatment consisted of two dosages of P4 and two dosages of OT. Explants were analyzed for total inositol monophosphate, bisphosphate (IP(2)), and trisphosphate (IP(3)) content. Preincubation with P4 for 10 min significantly interfered with OT stimulation of IP(2) and IP(3) synthesis. Oxytocin increased monophosphate production, but there was no detectable effect of P4. In the next experiment, endometrial explants were cultured in the absence or the presence of arachidonic acid. Explants were then exposed for 1 h to medium containing vehicle or P4. After incubation, explants were challenged with OT and the media were collected and analyzed for 13,14 dihydro-15-keto prostaglandin F(2alpha) by RIA. Treatment of explants with AA increased PGF(2alpha) content compared with that of controls. Brief exposure to P4 significantly decreased OT-induced PGF(2alpha) secretion from explants previously exposed to medium or AA. Collectively, these data are interpreted to indicate that the observed reduction in OT-induced IP(2) and IP(3) production and OT-induced PGF(2alpha) secretion was due to P4 inhibition of OT binding to its receptor.