Luteinizing Hormone Surge Research Articles

Semen characteristics and second successful artificial insemination of Asian elephant (Elephas maximus) in Thailand.

Background and Aim:As the number of wild Asian elephants (Elephas maximus) continues to decline, maintaining healthy populations under human care is vital. Male fertility assessment is essential for understanding the reproductive status, which can help to uncover underlying problems and improve the rate of pregnancy success. The objectives of this study in Asian elephants were as follows: (1) To investigate the semen characteristics; (2) to compare the relative seminal vesicle size and semen characteristics; (3) to compare the semen characteristics between good-motile (>60% progressive motility) and poor-motile (<60% progressive motility) ejaculates; and (4) to investigate the pregnancy success rate after artificial insemination (AI) with combined chilled and frozen semen.Materials and Methods:In total, 153 ejaculates were collected by manual rectal stimulation from 25 bulls. The volume, pH, sperm concentration, progressive motility, viability, morphology, and membrane integrity were investigated in each ejaculate. Assessment of accessory sex glands was conducted using transrectal ultrasonography to compare the relative seminal vesicle size and semen characteristics, and the bulls were divided into two groups according to the size of the ampulla (<7 or ≥7 cm2). For the comparison of good and poor-motile ejaculates and semen characteristics, the samples were divided into two groups: Good-motile (>60% progressive motility) and poor-motile (<60% progressive motility) ejaculates. Semen ejaculates for AI were collected from three bulls. The estrous cycles of four females were monitored using an enzyme immunoassay. Seven AI attempts were conducted using frozen and/or chilled semen by endoscopic visualization. AI was repeated 1 day before the luteinizing hormone surge, on the day of the surge, and 1 day after the surge. Pregnancy was confirmed by monitoring the serum progesterone profile and the abdomen and mammary glands changes.Results:From 153 ejaculates, the mean±standard error values of progressive motility, semen volume, sperm concentration, pH, and viability were 40.18%±2.28%, 40.94±3.86 mL, 1,205.58±62.26×106 sperm/mL, 7.50±0.10, and 56.17%±1.96%, respectively. Comparing ampulla size and semen characteristics revealed that the bulls with ampullae of ≥7 cm2 yielded significantly larger volume ejaculates. However, there were no significant differences in sperm motility and concentration. The comparison of semen characteristics between good- and poor-motile ejaculates revealed that the former had significantly higher pH, viability, normal acrosomes, intact membranes, and normal head and tail morphology but often had a significantly lower volume and sperm concentration. From seven AI attempts in four females, one female had a confirmed pregnancy (14.3% pregnancy rate), and delivered a healthy live female baby weighing 128 kg at 21 months and 12 days of gestation. The baby is now 3 years old and in a healthy condition, with normally developing growth and behavior.Conclusion:The semen characteristics of Asian elephants can be used as the baseline reference for further applications. The ampullae size indicates semen quantity but not quality. Our success in producing an elephant calf from AI using frozen and chilled semen demonstrated that AI can be used as an alternative approach for the breeding management of Asian elephants. However, the semen of Asian elephants is of poor quality, especially in terms of membrane integrity; thus, the improvement in semen quality through intensive and careful management of elephant health and fertility remains a challenge for the future. Furthermore, a sperm bank should be established to develop sperm cryopreservation, which will be invaluable for improving the genetic diversity of the Asian elephant.

Bidirectional communication in oogenesis: a dynamic conversation in mice and Drosophila.

In most animals, the oocyte is the largest cell by volume. The oocyte undergoes a period of large-scale growth during its development, prior to fertilization. At first glance, tissues that support the development of the oocyte in different organisms have diverse cellular characteristics that would seem to prohibit functional comparisons. However, these tissues often act with a common goal of establishing dynamic forms of two-way communication with the oocyte. We propose that this bidirectional communication between oocytes and support cells is a universal phenomenon that can be directly compared across species. Specifically, we highlight fruit fly and mouse oogenesis to demonstrate that similarities and differences in these systems should be used to inform and design future experiments in both models.

Uterine HOXA11 antisense long non-coding RNA prevents decidualization: A new pathway-regulating pregnancy

To achieve a successful pregnancy, coordinated development of the embryo and uterine endometrium are normally archived by coupling ovulation to progesterone production. A surge of pituitary luteinizing hormone triggers the release of oocytes and simultaneously initiates the conversion of the ovarian follicle to the corpus luteum, which produces large quantities of progesterone. Progesterone, in turn, drives endometrial differentiation, also known as decidualization. The decidualized endometrium is briefly receptive to the developing embryo, allowing the embryo to attach and implant in the uterine endometrium, thus establishing the early pregnancy.

Efficacy and safety of newly developed ganirelix acetate in infertile women for assisted reproductive technology: a prospective, randomised, controlled study

This study aimed to investigate the efficacy of Ganilever pre-filled syringe (PFS), a newly developed ganirelix acetate, for the inhibition of premature luteinising hormone (LH) surge in in vitro fertilisation (IVF). A prospective randomised controlled study was conducted (NCT03051087). A total of 236 women (Ganilever group: 114, Orgalutran group: 122) were finally analysed. The patients with LH of >10 mIU/mL on the day of human chorionic gonadotropin (hCG) injection were 0 (0.0%) and 3 (2.5%) in the Ganilever and Orgalutran groups, respectively (p= .25). The number of retrieved oocytes from two groups did not show any significant difference (12.0 ± 6.4 vs. 11.8 ± 6.3, p= .73). Furthermore, the two groups did not show significant differences in the number of good-quality oocytes and embryo, and the rate of fertilisation. Similar safety profiles were also observed. In conclusion, Ganilever PFS showed comparable IVF outcomes and safety profile in IVF, as compared to the Orgalutran. Impact Statement What is already known on this subject? Premature LH surge during controlled ovarian stimulation results in the induction of luteinisation of the immature follicles. Thus, gonadotrophin-releasing hormone (GnRH) antagonist protocol was suggested as an option for suppression of premature LH surge. Currently, one of GnRH antagonists being widely used is ganirelix acetate (Orgalutran®; Organon, Oss, The Netherlands). Ganilever pre-filled syringe (PFS) is a newly developed GnRH antagonist containing ganirelix acetate as an active ingredient. What do the results of this study add? Our study demonstrated that Ganilever PFS showed comparable IVF outcomes and patient safety profile in infertile women undergoing in IVF-ET, as compared to the Orgalutran. What are the implications of these findings for clinical practice and/or further research? The results of our study will provide another available GnRH antagonist to be used in patients with IVF.

Lifetime changes of the oocyte pool: Contributing factors with a focus on ovulatory inflammation.

In mammalian species, females are born with a number of oocytes exceeding what they release via ovulation. In humans, an average girl is born with over a thousand times more oocytes than she will ovulate in her lifetime. The reason for having such an excessive number of oocytes in a neonatal female ovary is currently unknown. However, it is well established that the oocyte number decreases throughout the entire lifetime until the ovary loses them all. In this review, data published in the past 80 years were used to assess the current knowledge regarding the changing number of oocytes in humans and mice, as well as the reported factors that contribute to the decline of oocyte numbers. Briefly, a collective estimation indicates that an average girl is born with approximately 600,000 oocytes, which is 2,000 times more than the number of oocytes that she will ovulate in her lifetime. The oocyte number begins to decrease immediately after birth and is reduced to half of the initial number by puberty and almost zero by age 50 years. Multiple factors that are either intrinsic or extrinsic to the ovary contribute to the decline of the oocyte number. The inflammation caused by the ovulatory luteinizing hormone surge is discussed as a potential contributing factor to the decline of the oocyte pool during the reproductive lifespan.

Does elevated luteinizing hormone level before trigger mean premature luteinizing hormone surge in advanced-aged women undergoing mild ovarian stimulation?

Objective To explore whether elevated luteinizing hormone (LH) level before trigger means premature LH surge in advanced aged women undergoing mild ovarian stimulation. Methods To retrospectively analyze 235 in vitro fertilization/intracytoplasmic sperm injection cycles in women >35 years old with the poor ovarian response (POR) from January 2012 to March 2016. Cycles are named Group 1, Group 2, and Group 3, being treated with gonadotropin-releasing hormone antagonist protocol (76 cycles), mild stimulation protocol using clomiphene citrate (73 cycles), and tamoxifen (86 cycles), respectively. Main outcome measure(s) The dynamic change of LH level during stimulation; the proportion of an elevated LH level defined as >10 IU/L on trigger day; the proportion of premature ovulation in each group. Results Serum LH level increased early in Group 2 and Group 3 and remained significantly higher than that in Group 1 during stimulation. In a sequence of three groups, the proportion of elevated LH levels before the trigger was 11.84, 43.8, and 37.21% (p＜.001) respectively. And the proportion of premature ovulation in patients with elevated LH levels was 11.11, 18.75, and 25% (p = .11) respectively. Conclusion Elevated LH level before trigger does not mean premature LH surge in women more than 35 years old with POR undergoing mild ovarian stimulation with clomiphene or tamoxifen.

Estrogen upregulates the firing activity of hypothalamic gonadotropin-releasing hormone (GnRH1) neurons in the evening in female medaka.

The reproductive function of vertebrates is regulated by the hypothalamic-pituitary-gonadal axis. In sexually mature females, gonadotropin-releasing hormone (GnRH) neurons in the preoptic area (POA) are assumed to be responsible for a cyclic large increase in GnRH release, the GnRH surge, triggering a luteinizing hormone (LH) surge, which leads to ovulation. Precise temporal regulation of the preovulatory GnRH/LH surge is important for successful reproduction because ovulation should occur after follicular development. The time course of the circulating level of estrogen is correlated with the ovulatory cycle throughout vertebrates. However, the neural mechanisms underlying estrogen-induced preovulatory GnRH surge after folliculogenesis still remain unclear, especially in non-mammals. Here, we used a versatile non-mammalian model medaka for the analysis of the involvement of estrogen in the regulation of POA-GnRH (GnRH1) neurons. Electrophysiological analysis using a whole brain-pituitary in vitro preparation, which maintains the hypophysiotropic function of GnRH1 neurons intact, revealed that 17β-estradiol (E2 ) administration recovers the ovariectomy-induced lowered GnRH1 neuronal activity in the evening, indicating the importance of E2 for upregulation of GnRH1 neuronal activity. The importance of E2 was also confirmed by the fact that GnRH1 neuronal activity was low in short-day photoperiod-conditioned females (low E2 model). However, E2 failed to upregulate the firing activity of GnRH1 neurons in the morning, suggesting the involvement of additional time-of-day signal(s) for triggering GnRH/LH surges at an appropriate timing. We also provide morphological evidence for the localization of estrogen receptor subtypes in GnRH1 neurons. In conclusion, we propose a working hypothesis in which both estrogenic and time-of-day signals act in concert to timely upregulate the firing activity of GnRH1 neurons that trigger the GnRH surge at an appropriate timing in a female-specific manner. This neuroendocrinological mechanism is suggested to be responsible for the generation of ovulatory cycles in female teleosts in general.

Intact luteinizing hormone, LHβ, and LHβ core fragment in urine of menstruating women.

We examined different molecular forms of luteinizing hormone (LH) in urine samples taken during periovulatory days with the aim of revealing different forms of LH immunoreactivity (LH-ir) in normally menstruating women. Serum and first-morning-voided urine serum samples were obtained from six healthy, 22 to 38 years old, regularly menstruating women during their periovulatory days based on their previous menstrual cycles. The day of the LH surge was determined on the basis of serum LH concentrations and confirmed by an at least two-fold increase in urinary concentrations of intact LH on consecutive days. Different molecular forms of LH-ir were identified by gel filtration of first-morning-voided urine samples obtained from regularly menstruating women on periovulatory days. Different forms of LH immunoreactivity (LH-ir) were distinguished as intact LH, its free beta-subunit (LHβ), and the core fragment of LHβ (LHβcf) according to their molecular sizes. The latter two are also called non-intact LH. Intact LH was the dominating form on the day before and on the day of LH surge while LHβcf was the major form of LH immunoreactivity after the LH surge for the following 5-7 days. LHβ was detected on the day of the LH surge as well as on the following day. These results indicate that LH is degraded in the kidneys and excreted as LHβ, and mainly as LHβcf for 7 days following the LH peak.

The Effect of Photoperiodic Conditions on GnRH/LH Secretion in Ewes.

Simple SummaryDuring the course of evolution, animals have evolved biological rhythms that are associated with changes in the lighting and temperature of their environment. Females in most breeds of sheep are seasonal breeders, with ovulatory cycles occurring in the autumn and winter and anovulation in the spring and summer. Secretion of gonadotropin releasing hormone and luteinizing hormone, the main hormones regulating reproduction in females, displays a circadian pattern; however, data concerning the day/night differences in their secretion in ewes are incomplete. The aim of the undertaken study was to determine the day/night differences in the secretion of gonadotropin releasing hormone and luteinizing hormone in follicular phase and anestrous ewes. It was demonstrated that secretion of investigated hormones is subject to diurnal and seasonal changes. The observed reduction in luteinizing hormone release, a few hours after the sunset, seems to be universal for both the anestrus and follicular phase. It could be concluded that the nocturnal suppression of luteinizing hormone secretion in follicular phase ewes may be a mechanism moving this hormone surge to the early morning.Secretion of gonadotropin releasing hormone (GnRH) and luteinizing hormone (LH) displays a circadian pattern. Data concerning differences in daily GnRH/LH secretion during different seasons in sheep are fragmentary. The aim of the study was to determine day/night differences in GnRH/LH secretion in the follicular phase and in the anestrous ewes. The studies were performed on Blackhead ewes (n = 24). Ewes from each season were divided into two groups of six animals (day and night group). The animals were euthanized 5 h after sunset or 5 h after sunrise and blood was taken to determine LH and melatonin concentrations. In the hypothalamus, the expression of GnRH and gonadotropin releasing hormone receptor (GnRHR) was determined. In the anterior pituitary, the expression of mRNA encoding subunit β of LH (LHβ) and GnRHR was assayed. Our study showed that GnRH/LH secretion is subject to diurnal and seasonal changes. The observed reduction in LH release, a few hours after the sunset, seems to be universal for both the anestrus and follicular phase, when the processes occurring at the hypothalamus are more equivocal. It could be concluded that the nocturnal suppression of LH secretion in follicular phase ewes may be a mechanism moving the LH surge to the early morning.

Algorithms with Area under the Curve for Daily Urinary Estrone-3-Glucuronide and Pregnanediol-3-Glucuronide to Signal the Transition to the Luteal Phase.

Background and Objectives: Home fertility assessment methods (FAMs) for natural family planning (NFP) have technically evolved with the objective metrics of urinary luteinizing hormone (LH), estrone-3-glucuronide (E3G) and pregnanediol-3-glucuronide (PDG). Practical and reliable algorithms for timing the phase of cycle based upon E3G and PDG levels are mostly unpublished and still lacking. Materials and Methods: A novel formulation to signal the transition to the luteal phase was discovered, tested, and developed with a data set of daily E3G and PDG levels from 25 women, 78 cycles, indexed to putative ovulation (day after the urinary LH surge), Day 0. The algorithm is based upon a daily relative progressive change in the ratio, E3G-AUC/PDG-AUC, where E3G-AUC and PDG-AUC are the area under the curve for E3G and PDG, respectively. To improve accuracy the algorithm incorporated a three-fold cycle-specific increase of PDG. Results: An extended negative change in E3G-AUC/PDG-AUC of at least nine consecutive days provided a strong signal for timing the luteal phase. The algorithm correctly identified the luteal transition interval in 78/78 cycles and predicted the start day of the safe period as: Day + 2 in 10/78 cycles, Day + 3 in 21/78 cycles, Day + 4 in 28/78 cycles, Day + 5 in 15/78 cycles, and Day + 6 in 4/78 cycles. The mean number of safe luteal days with this algorithm was 10.3 ± 1.3 (SD). Conclusions: An algorithm based upon the ratio of the area under the curve for daily E3G and PDG levels along with a relative PDG increase offers another approach to time the phase of cycle. This may have applications for NFP/FAMs and clinical evaluation of ovarian function.

Dual trigger with gonadotropin-releasing hormone agonist and human chorionic gonadotropin significantly improves oocyte yield in normal responders on GnRH-antagonist cycles.

ObjectiveDuring in vitro fertilization (IVF) cycles, final oocyte maturation is usually triggered by human Chorionic Gonadotropin (hCG) for its known effect in mimicking Luteinizing Hormone (LH) surge; however, with the widespread use of the ‘antagonist protocol’, Gonadotropin Releasing Hormone agonist (GnRHa) is being more commonly employed as a trigger in order to minimize or eliminate the risk of ovarian hyper-stimulation syndrome (OHSS). Many studies proved its efficacy in inducing oocyte maturation and its safety in preventing OHSS in high-risk groups. Moreover, some studies showed that GnRHa trigger may improve oocyte yield. This study aimed to further explore any beneficial effect of adding GnRHa to hCG (dual trigger) on oocyte yield and fertilization rate in normal responder women.MethodsWe retrospectively reviewed and analyzed the data from 127 patients on antagonist protocol (67 dual trigger and 60 HCG trigger).ResultsThe number of total oocytes, the number of MII oocytes and the number of fertilized oocytes were all significantly higher with the dual trigger protocol compared to hCG-only trigger. However, there is no significant difference in clinical pregnancy rate.ConclusionsUsing the dual trigger improved the number and quality of oocytes, and the fertilization rate in normal responders.

Progestin primed ovarian stimulation protocol: current status in assisted reproductive technology

Progestin primed ovarian stimulation (PPOS) is a novel controlled ovarian stimulation protocol. Prevention of endogenous luteinizing hormone surge is an important step in assisted reproductive technology cycles. Gonadotropin-releasing hormone (GnRH) analogs are used conventionally for preventing premature ovulation before egg retrieval. However, GnRH analogs – both agonists and antagonists – have certain disadvantages such as increased cost, the requirement of daily injections, patient inconvenience, and adverse effects, which have prompted us to search for possible alternatives. Oral progesterone has been used recently as an effective alternative to GnRH analogs. Although the use of progestin requires mandatory cryopreservation of all the embryos due to embryo-endometrium asynchrony, advances in freezing techniques have rendered it feasible. Moreover, progestin is cost-effective, administered orally, convenient, and easily accessible. Hence, this new PPOS protocol combined with freeze-all cycles is an effective alternative to GnRH analogs for pituitary suppression during ovarian stimulation. This review aims to evaluate the current status of the PPOS protocol, its mechanism, different regimes, advantages, and disadvantages.

Comparing Progesterone Primed Ovarian Stimulation (PPOS) to GnRH Antagonist Protocol in Oocyte Donation Cycles.

Progesterone-primed ovarian stimulation (PPOS) protocol is based on the principle of preventing pre-mature luteinising hormone surge during ovarian stimulation using progesterone. In this study, we aimed to compare the cost-effectiveness of PPOS over GnRH antagonist cycles in oocyte donor cycles where freeze all is a norm. It is a prospective cohort study with 130 participants. We included all women undergoing oocyte donation using PPOS protocol and antagonist protocol at our centre. Fifty-seven belonged to the PPOS group and were given medroxyprogesterone acetate (MPA) and 73 belonged to the GnRH antagonist group who received cetrorelix. The primary outcome was the number of mature oocyte retrieved at OPU and the cost involved per stimulation cycle. For normally distributed observations, we used t-test, and for the variables of non-normal distribution, Mann-Whitney U-test was used. The significance was accepted for P < 0.05. The baseline clinical characteristics of the donors were comparable with a mean age of 25.42 ± 2.90 years, body mass index of 24.00 ± 4.00 kg/m2 and antral follicle count of 18.63 ± 5.23. The duration of stimulation was similar in both the groups as well as the total gonadotropin dose required was not significantly different. The number of mature oocytes retrieved was same in both the groups (10.41 ± 4.04 with antagonist and 10.25 ± 3.23 with PPOS, P = 0.964). There were no reported cases of severe ovarian hyperstimulation syndrome (OHSS) in any of the groups. The incidence of mild-to-moderate OHSS in the antagonist group was 5.4% and in the PPOS group was 3.6%, and the difference was not significant (P = 0.69). The cost per mature oocyte (M2) was significantly higher in the antagonist protocol in comparison to the PPOS protocol (INR 9485.69 ± 5751.11 vs. Rs. 5945.86 ± 2848.59, respectively, P < 0.001). Our study identifies PPOS protocol using MPA to be more cost-effective and patient-friendly than conventional GnRH antagonist protocol in oocyte donor cycles.

Circadian Rhythms in the Neuronal Network Timing the Luteinizing Hormone Surge.

For billions of years before electric light was invented, life on Earth evolved under the pattern of light during the day and darkness during the night. Through evolution, nearly all organisms internalized the temporal rhythm of Earth's 24-hour rotation and evolved self-sustaining biological clocks with a ~24-hour rhythm. These internal rhythms are called circadian rhythms, and the molecular constituents that generate them are called molecular circadian clocks. Alignment of molecular clocks with the environmental light-dark rhythms optimizes physiology and behavior. This phenomenon is particularly true for reproductive function, in which seasonal breeders use day length information to time yearly changes in fertility. However, it is becoming increasingly clear that light-induced disruption of circadian rhythms can negatively impact fertility in nonseasonal breeders as well. In particular, the luteinizing hormone surge promoting ovulation is sensitive to circadian disruption. In this review, we will summarize our current understanding of the neuronal networks that underlie circadian rhythms and the luteinizing hormone surge.

The roles of kisspeptin and neurokinin B in GnRH pulse generation in humans, and their potential clinical application.

The delivery of gonadotropin-releasing hormone (GnRH) in a pulsatile mode to the gonadotropes has long been known to be essential for normal reproductive function. There have been numerous studies aimed at dissecting out the mechanisms underlying GnRH pulse generation. The discovery of kisspeptin as an upstream regulator of GnRH attracted the possibility that pulsatile kisspeptin governed the pulsatile secretion of GnRH. Subsequent studies have shown the importance of the neurokinin B (NKB) system in modulating kisspeptin secretion and this GnRH. A number of studies in laboratory rodents have supported this notion. By contrast, we present data from clinical studies in men and women, in a range of contexts, showing that continuous infusion of kisspeptin 10 at receptor-saturating levels gives rise to an increase in luteinizing hormone (LH) (GnRH) pulse frequency. This has been demonstrated in normal healthy and hypogonadal men, in normal women during the mid-cycle LH surge, in men and women with mutations in the genes encoding NKB or its receptor, neurokinin 3 receptor (NK3R), in women with polycystic ovary syndrome treated with NK3R antagonist, and in women treated with NK3R antagonist during the LH surge. These finds indicate that pulsatile secretion and action of kisspeptin on GnRH neurons is not required for the generation of LH (GnRH) pulses in humans. We also report that there is an absence of desensitization in humans exposed to continuous infusion of kisspeptin-10 at receptor-saturating concentrations over 22h and briefly review GnRH, kisspeptin and NKB analogs and their clinical application.

Addition of a carboxy-terminal tail to the normally tailless gonadotropin-releasing hormone receptor impairs fertility in female mice.

Gonadotropin-releasing hormone (GnRH) is the primary neuropeptide controlling reproduction in vertebrates. GnRH stimulates follicle-stimulating hormone (FSH) and luteinizing hormone (LH) synthesis via a G-protein-coupled receptor, GnRHR, in the pituitary gland. In mammals, GnRHR lacks a C-terminal cytosolic tail (Ctail) and does not exhibit homologous desensitization. This might be an evolutionary adaptation that enables LH surge generation and ovulation. To test this idea, we fused the chicken GnRHR Ctail to the endogenous murine GnRHR in a transgenic model. The LH surge was blunted, but not blocked in these mice. In contrast, they showed reductions in FSH production, ovarian follicle development, and fertility. Addition of the Ctail altered the nature of agonist-induced calcium signaling required for normal FSH production. The loss of the GnRHR Ctail during mammalian evolution is unlikely to have conferred a selective advantage by enabling the LH surge. The adaptive significance of this specialization remains to be determined.

Progesterone receptor-Src kinase signaling pathway mediates neuroprogesterone induction of the luteinizing hormone surge in female rats.

Neural circuits in female rats are exposed to sequential estradiol and progesterone to regulate the release of luteinizing hormone (LH) and ultimately ovulation. Estradiol induces progesterone receptors (PGRs) in anteroventral periventricular nucleus (AVPV) kisspeptin neurons, and as estradiol reaches peak concentrations, neuroprogesterone (neuroP) synthesis is induced in hypothalamic astrocytes. This local neuroP signals to PGRs expressed in kisspeptin neurons to trigger the LH surge. We tested the hypothesis that neuroP-PGR signaling through Src family kinase (Src) underlies the LH surge. As observed in vitro, PGR and Src are co-expressed in AVPV neurons. Estradiol treatment increased the number of PGR immunopositive cells and PGR and Src colocalization. Furthermore, estradiol treatment increased the number of AVPV cells that had extranuclear PGR and Src in close proximity (<40nm). Infusion of the Src inhibitor (PP2) into the AVPV region of ovariectomized/adrenalectomized (ovx/adx) rats attenuated the LH surge in trunk blood collected 53h post-estradiol (50µg) injection that induced neuroP synthesis. Although PP2 reduced the LH surge in estradiol benzoate treated ovx/adx rats, activation of either AVPV PGR or Src in 2µg estradiol-primed animals significantly elevated LH concentrations compared to dimethyl sulfoxide infused rats. Finally, antagonism of either AVPV PGR or Src blocked the ability of PGR or Src activation to induce an LH surge in estradiol-primed ovx/adx rats. These results indicate that neuroP, which triggers the LH surge, signals through an extranuclear PGR-Src signaling pathway.

Deletion of Gαq/11 or Gαs Proteins in Gonadotropes Differentially Affects Gonadotropin Production and Secretion in Mice.

Gonadotropin-releasing hormone (GnRH) regulates gonadal function via its stimulatory effects on gonadotropin production by pituitary gonadotrope cells. GnRH is released from the hypothalamus in pulses and GnRH pulse frequency differentially regulates follicle-stimulating hormone (FSH) and luteinizing hormone (LH) synthesis and secretion. The GnRH receptor (GnRHR) is a G protein-coupled receptor that canonically activates Gα q/11-dependent signaling on ligand binding. However, the receptor can also couple to Gα s and in vitro data suggest that toggling between different G proteins may contribute to GnRH pulse frequency decoding. For example, as we show here, knockdown of Gα s impairs GnRH-stimulated FSH synthesis at low- but not high-pulse frequency in a model gonadotrope-derived cell line. We next used a Cre-lox conditional knockout approach to interrogate the relative roles of Gα q/11 and Gα s proteins in gonadotrope function in mice. Gonadotrope-specific Gα q/11 knockouts exhibit hypogonadotropic hypogonadism and infertility, akin to the phenotypes seen in GnRH- or GnRHR-deficient mice. In contrast, under standard conditions, gonadotrope-specific Gα s knockouts produce gonadotropins at normal levels and are fertile. However, the LH surge amplitude is blunted in Gα s knockout females and postgonadectomy increases in FSH and LH are reduced both in males and females. These data suggest that GnRH may signal principally via Gα q/11 to stimulate gonadotropin production, but that Gα s plays important roles in gonadotrope function in vivo when GnRH secretion is enhanced.

Progestin-Primed Ovarian Stimulation with Clomiphene Citrate Supplementation May Be More Feasible for Young Women with Diminished Ovarian Reserve Compared with Standard Progestin-Primed Ovarian Stimulation: A Retrospective Study.

PurposeThe present study was designed to compare the efficiency of the progestin-primed ovarian stimulation (PPOS) protocol with clomiphene citrate (CC) supplementation (PPOS+CC) and the standard PPOS protocol for women of different ages with diminished ovarian reserve (DOR).Patients and MethodsThis retrospective cohort study included 364 DOR women who underwent controlled ovarian stimulation with PPOS+CC (n = 223) or standard PPOS (n = 141). They were divided into subgroups based on age: ≤35 years and >35 years. Differences in baseline characteristics, ovarian stimulation characteristics, endocrinological characteristics, and clinical outcome between the two groups were assessed. Statistical analyses were stratified by age.ResultsIn all women with DOR, PPOS+CC was associated with a lower percentage of women with profound pituitary suppression than standard PPOS (0.0% vs 18.6%, P < 0.001 and 1.3% vs 11.0%, P = 0.002). In young women with DOR, more high-quality cleavage-stage embryos were harvested (1.96 vs 1.38, P = 0.018) and a lower dosage of gonadotropin per oocyte retrieved was required (558.37 vs 909.82, P = 0.036) in PPOS+CC. In older women with DOR, PPOS+CC led to an increase in the incidence of luteinizing hormone (LH) surge levels above 10 IU/L on trigger day (12.7% vs 4.9%, P = 0.028) and a decrease in the rate of oocyte maturation (84.7% vs 89.9%, P = 0.034) compared to standard PPOS.ConclusionClomiphene citrate is an effective adjuvant to alleviate pituitary suppression in PPOS protocols; for young women with DOR, CC supplementation had a positive impact on the number of high-quality embryos. However, older women with DOR would be at risk of developing a premature LH surge and having poor oocyte maturation rate under the PPOS+CC protocol.

The efficacy of dydrogesterone use to suppress premature luteinizing hormone surge on cycle outcomes in controlled ovarian stimulation

Objective: Progestins are used as an alternative to gonadotropin releasing hormone (GnRH) antagonists to suppress premature luteinizing hormone (LH) surge and a flexible protocol has been defined recently. The aim of this study was to compare the efficacy of flexible protocols with dydrogesterone and GnRH antagonist in suppressing LH surge.Material and Methods: This retrospective, case-control study, was conducted in an infertility unit of a tertiary university hospital. A daily dose of 40 mg dydrogesterone was compared with GnRH antagonist (GnRHant) in controlled ovarian hyperstimulation cycles between July 2018 and July 2019. Dydrogesterone was started when the leading follicle was 12 mm or serum estradiol was over 300 pg/mL. A subgroup analysis of poor responder patients was also performed.Results: In total there were 105 subjects aged between 23 and 41 years, 52 in the dydrogesterone group and 53 in the GnRHant group. Duration of pituitary suppression was longer in dydrogesterone group. Premature ovulation was observed in 11.5% (6/52) and 0% in the dydrogesterone and GnRHant groups, respectively. However, collected oocyte counts and metaphase II oocyte counts were found to be similar between the groups. The six patients with premature ovulation were in poor responder subgroup.Conclusion: Dydrogesterone can be used as an alternative to antagonist regimen in patients where embryo transfer is not planned in the same cycle. However, flexible regimen may not be appropriate in patients with diminished ovarian reserve, as advanced follicular maturation and delayed suppressive effect of oral progesterone may cause premature ovulation. Randomized controlled trials in particular patient groups are required to determine the most effective minimum dose and time of application to ensure treatment success.