Blockade by progesterone of estrogen-induced LH and FSH release in the rhesus monkey

Comparison of progesterone protocol versus gonadotropin-releasing hormone antagonist protocol in terms of preventing premature LH surge and assisted reproductive technology outcome in infertile women: a randomized controlled trial

INTRODUCTION

Progesterone can be used instead of GnRH agonists and antagonists in order to avert a premature LH surge during controlled ovarian stimulation (COS) protocol. Nonetheless, there is limited knowledge regarding its utilization. Thus, this study compared the effects of progesterone and GnRH antagonists (GnRH-ant) on premature LH surges and assisted reproductive technology (ART) results in infertile women undergoing ART.

MATERIALS AND METHODS

In this clinical trial, the progesterone protocol (study group) and GnRH-ant protocol (control group) were tested in 300 infertile individuals undergoing IVF/ICSI. The main outcome was the number of oocytes retrieved. The secondary outcomes included premature LH rise/surge, the quantity of follicles measuring ≥ 10 and 14 mm, oocyte maturity and fertilization rate, the number of viable embryos, high-quality embryo rate and pregnancy outcomes.

RESULTS

The study group exhibited a statistically significant increase in the number of retrieved oocytes, follicles measuring 14 mm or greater, and viable embryos compared to the control group (P < 0.05). The study group also increased oocyte maturity, chemical pregnancy rate, and clinical pregnancy rate (P < 0.05). Both groups had similar mean serum LH, progesterone, and E2 levels on trigger day. The control group had more premature LH rise than the study group, although this difference was not statistically significant.

CONCLUSION

In conclusion, it can be stated that the progesterone protocol and the GnRH-ant protocol exhibit similar rates of sudden premature LH surge in infertile patients. However, it is important to note that the two regiments differ in their outcomes in ART.

TRIAL REGISTRATION

This study was retrospectively registered in the Iranian website ( www.irct.ir ) for clinical trials registration ( http://www.irct.ir : IRCT-ID: IRCT20201029049183N, 2020-11-27).

Letrozole cotreatment progestin-primed ovarian stimulation in women undergoing controlled ovarian stimulation for in vitro fertilization

AIM

To investigate the impact of letrozole cotreatment progestin-primed ovarian stimulation (PPOS) (Le PPOS) in controlled ovarian stimulation (COS) and the pregnancy outcomes in frozen-thawed embryo transfer cycles.

METHODS

This retrospective cohort study included women who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). A total of 2575 cycles were included (1675 in the Le PPOS group and 900 in the PPOS group). The primary outcome was the clinical pregnancy rates. The secondary outcome was the live birth rates.

RESULTS

In this study, propensity score matching (PSM) was performed to create a perfect match of 379 patients in each group. After matching, the numbers of oocytes retrieved, mature oocytes, fertilization, and clinical pregnancy rates were more favorable in the Le PPOS group than in the PPOS group (all p < 0.05). The multivariable analysis showed that the clinical pregnancy rate was higher in the Le PPOS than in the PPOS group (odds ratio = 1.46, 95% confidence interval: 1.05-2.04, p = 0.024) after adjusting for potentially confounding factors (age, anti-Müllerian hormone levels, antral follicular count, the type of embryo transferred, number of transferred embryos, body mass index, and follicular stimulating hormone and estradiol levels on starting day).

CONCLUSIONS

This retrospective study with a limited sample size suggests that the Le PPOS protocol might be an alternative to the PPOS protocol in women undergoing COS and could lead to better pregnancy outcomes. The results should be confirmed using a formal randomized controlled trial.

Luteinizing Hormone Suppression by Progestin-Primed Ovarian Stimulation Is Associated With Higher Implantation Rate for Patients With Polycystic Ovary Syndrome Who Underwent in vitro Fertilization/Intracytoplasmic Sperm Injection Cycles: Comparing With Short Protocol

Background

Many studies have demonstrated the positive clinical value of progestin-primed ovarian stimulation (PPOS) in patients with polycystic ovary syndrome (PCOS) who underwent assisted reproductive technology. However, the underlying factors contributing to this phenomenon remain unclear. We conducted a retrospective observational study to compare the clinical outcomes of women with PCOS who underwent PPOS or the short protocol to identify possible factors that influence the outcome.

Methods

This study included 304 patients who underwent PPOS and 152 patients who underwent short protocol from April 2014 to July 2019 after propensity-score matching. Human menopausal gonadotropin (hMG) dose, hormone profile, embryo development, and clinical outcomes of frozen-thawed embryo transfer (FET) cycles were compared. The primary outcome measure was the implantation rate. Logistic regression was performed to identify contributing factors, and receiver operating characteristic curve analysis was used to calculate the cutoff of luteinizing hormone (LH) difference ratio in clinical outcomes.

Results

Compared with the short protocol, PPOS resulted in a higher implantation rate (43.4% vs. 31.9%, P < 0.05), clinical pregnancy rate (61.8% vs. 47.4%, P < 0.05), and live birth rate (48.4% vs. 36.8%, P < 0.05). Similar fertilization, cleavage, and valid embryo rate per oocyte retrieved between groups were observed. The LH difference ratio was positively associated with implantation rate [P = 0.027, odds ratio (OR) = 1.861, 95% CI: 1.074–3.226]. The relationship between the LH difference ratio with clinical outcomes was confirmed by receiver operating characteristic curve analysis and comparisons among patients grouped by the LH difference ratio.

Conclusion

The implantation rate was associated with the LH difference ratio during ovary stimulation in patients with PCOS. Our results provide the explanation why PPOS shows the positive clinical outcomes for patients with PCOS.

Dexamethasone application for in vitro fertilisation in non-classic 17-hydroxylase/17,20-lyase-deficient women

CONTEXT

High progesterone levels in the follicular stage interfere with the implantation window, causing infertility in women with 17-hydroxylase/17,20-lyase deficiency (17OHD). Dexamethasone can restore cortisol deficiency and suppress inappropriate mineralocorticoid secretion to control hypertension in 17OHD patients, but poses risks to the foetus if administered during pregnancy.

OBJECTIVE

We prospectively explored a rational glucocorticoid use protocol for assistive reproduction in a woman with non-classic 17OHD that reduced glucocorticoid side effects.

METHOD

In this study, the treatment protocol for this 17OHD patient included the following steps. First, the appropriate type and dose of glucocorticoid for endogenous progesterone suppression was determined. Then, glucocorticoid was discontinued to increase endogenous progesterone levels for ovarian stimulation. Next, dexamethasone plus GnRHa were used to reduce progesterone levels in frozen embryos for transfer. Once pregnancy was confirmed, dexamethasone was discontinued until delivery.

RESULTS

Dexamethasone, but not hydrocortisone, reduced progesterone levels in the 17OHD woman. After endogenous progesterone-primed ovarian stimulation, 11 oocytes were retrieved. Seven oocytes were 2PN fertilised and four day-3 and two day-5 embryos were cryopreserved. After administering dexamethasone plus gonadotropin-releasing hormone agonist (GnRHa) to reduce progesterone levels to normal, hormone replacement therapy was administered until the endometrial width reached 9 mm. Exogenous progesterone (60 mg/day) was used for endometrial preparation. Two thawed embryos were transferred on day 4. Dexamethasone was continued until pregnancy confirmation on the 13^th day post-transfer. Two healthy boys, weighing 2100 and 2000 g, were delivered at 36 weeks' gestation.

CONCLUSION

Rational use of dexamethasone synchronised embryonic development with the endometrial implantation window, while not using in post-implantation avoided its side effects and promoted healthy live births in women non-classic 17OHD undergoing in vitro fertilisation.

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

Purpose

Patients and Methods

Results

Conclusion

Progestin-Primed Ovarian Stimulation Protocol for Patients in Assisted Reproductive Technology: A Meta-Analysis of Randomized Controlled Trials

Objectives

Progestin-primed ovarian stimulation (PPOS) is a new ovarian stimulation protocol that can block the luteinizing hormone (LH) surge through progesterone instead of traditional down regulating or gonadotropin-releasing hormone (GnRH) antagonist, and in order to achieve multi-follicle recruitment. This paper aims to investigate the effectiveness of PPOS and its suitability for infertile patients with different ovarian reserve functions.

Methods

We searched published randomized controlled trials (RCTs) about PPOS on Cochrane Library, PubMed, Embase, and Web of Science. The search period spanned from January 1, 2015 to November 16, 2020. The data were extracted, and the meta-analysis was performed on ovarian stimulation as well as embryological and clinical outcomes. The outcomes were pooled by a random effects model, and the risk of heterogeneity was evaluated. Subgroup analysis was performed for different ovarian reserve patients.

Results

The clinical pregnancy rates and live birth or ongoing pregnancy rates with the PPOS protocol were not different from those with the control group. In the diminished ovarian reserve (DOR) subgroup, the PPOS protocol had a lower rate of premature LH surge [RR = 0.03, 95% CI = 0.01 to 0.13, p < 0.001]. The PPOS protocol had a lower rate of ovarian hyperstimulation syndrome (OHSS) [RR = 0.52, 95% CI = 0.36 to 0.76, p < 0.001, I2 = 0.00%]. The secondary outcomes showed that the number of oocytes retrieved, MII oocytes, and viable embryos was higher than that of the control protocol in DOR patients [(MD = 0.33, 95% CI = 0.30 to 0.36, p < 0.001), (MD = 0.30, 95% CI = 0.27 to 0.33, p < 0.001), (MD = 0.21, 95% CI = 0.18 to 0.24, p < 0.001)] and normal ovarian reserve (NOR) patients [(MD = 1.41, 95% CI = 0.03 to 2.78, p < 0.001), (MD = 1.19, 95% CI = 0.04 to 2.35, p < 0.001), (MD = 1.01, 95% CI = 0.21 to 1.81, p = 0.01)].

Conclusion

The findings suggest that PPOS is an effective ovarian stimulation protocol and is beneficial for patients with different ovarian reserve functions, which needs to be validated in more RCTs with larger samples.

Granulosa cells apoptosis and follicular fluid hormones: comparison of progestin-primed ovarian stimulation versus GnRH antagonist protocols

OBJECTIVE

To explore the effect of progestin-primed ovarian stimulation protocol (PPOS) on mural granulosa cells (GCs) apoptosis and hormonal profiles in follicular fluid (FF) and efficacy over GnRH antagonist (GnRH-A) protocols.

METHODS

We performed a prospective cohort study from June through August 2017 at a tertiary teaching hospital. 63 Patients meeting our criteria were recruited in this prospective study voluntarily and stratified to PPOS or GnRH-A group randomly. Mural GCs and FF were collected during oocyte retrieval. Apoptosis of GCs was assessed using the Annexin V-affinity assay by flow cytometry and hormonal profiles in FF were measured using electrochemiluminescence.

RESULTS

A total of 63 women were assessed for eligibility, with 25 cases in PPOS group and 38 in GnRH-A group. Difference of early stage apoptosis rate, late stage apoptosis rate, and total apoptosis rate did not reach statistical significance between groups. Meanwhile, concentrations of hormones in FF were comparable in two groups. No statistically significant differences were observed in number of oocytes retrieved, mature oocyte rate, fertilization rate, and top-quality embryos rate. No patients experienced premature LH surge in both groups during the study.

CONCLUSION

Compared to GnRH antagonist protocol, PPOS had comparable laboratory outcomes, GCs apoptosis rate and hormonal profiles in FF. PPOS is an effective and safe alternative option to provide controlled ovarian hyperstimulation (COH).

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.

Comparison of Dydrogesterone and Medroxyprogesterone in the Progestin-Primed Ovarian Stimulation Protocol for Patients With Poor Ovarian Response

OBJECTIVE

To compare the clinical outcomes of dydrogesterone (DYG) and medroxyprogesterone (MPA) in the progestin-primed ovarian stimulation (PPOS) protocol for patients with poor ovarian response (POR).

PATIENTS AND METHODS

This was a retrospective cohort study. Women with POR who underwent IVF/ICSI at the Reproductive Center of Third Affiliated Hospital of Zhengzhou University between January 2020 and January 2021 were included. The primary outcome measure of our study was the number of oocytes retrieved. The secondary outcome measures in the present study were the number of 2PN, number of available embryos, oocyte retrieval rate, fertilization rate, viable embryo rate per oocyte retrieved, cancellation rate and pregnancy outcomes of the first embryo transfer cycle, including the biochemical pregnancy, clinical pregnancy and miscarriage rates.

RESULTS

In total, 118 women underwent hMG +DYG protocols, and 692 women who underwent hMG +MPA met the Bologna criteria for POR. After baseline characteristics were balanced using the PSM model, 118 hMG +DYG protocols were matched to 118 hMG +MPA protocols, and the baseline characteristics were comparable between the two groups. The numbers of oocytes retrieved, 2PN, and available embryos and the oocyte retrieval rate, fertilization rate, viable embryo rate per oocyte retrieved and cancellation rate of the hMG+DYG and hMG+MPA protocols were comparable. Altogether, 66 women in the hMG+DYG group and 87 women in the hMG+MPA group underwent first embryo transfers. In the hMG+DYG group, 81.8% (54/66) of the patients underwent cleavage embryo transfers; similarly, 79.3% (69/87) of patients in the hMG+MPA group had cleavage embryo transfers (P=0.70).The biochemical pregnancy rate of the hMG+DYG group was 42.4%, and this was comparable to the rate in the hMG+DYG group, at 34.5% (P=0.32). The clinical pregnancy rates were similar between the two groups (36.4% vs. 31.0%, P=0.49), and there was no significant difference in the rate of miscarriage between the two groups (12.5% vs. 29.6%, P=0.14).

CONCLUSION

For women with POR, the clinical outcome of the hMG + DYG group was similar to that of the hMG + MPA group, indicating that both combinations can be useful options for PPOS protocols.

Comparison of a progestin-primed ovarian stimulation protocol with a flexible GnRH antagonist protocol in patients with polycystic ovary syndrome who are participating in an IVF programme: study protocol for a randomised controlled trial

INTRODUCTION

Women with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization (IVF) protocols are typically characterised by an increased number of oocytes retrieved. The oocytes are often of poor quality, leading to lower pregnancy rates, higher miscarriage rates and an increased risk of developing ovarian hyperstimulation syndrome (OHSS). Since our previous preliminary study showed that a novel progestin-primed ovarian stimulation (PPOS) protocol blocked the luteinising hormone (LH) surge during IVF and achieved a higher pregnancy rate with a lower incidence of OHSS, we designed a prospective randomised controlled trial to compare the efficacy and safety of this PPOS protocol with the flexible gonadotropin-releasing hormone (GnRH) antagonist protocol in patients with PCOS who are undergoing IVF procedures.

METHODS AND ANALYSIS

Patients with PCOS will be randomised to one of two controlled ovarian stimulation regimens-GnRH antagonist or PPOS-using a computer-generated random number. A freeze-all strategy using embryo vitrification techniques and frozen embryo transfer will be performed in both groups. The primary outcome is the live-birth rate per transfer. Secondary outcomes include the incidence of premature LH surges, the duration and total dose of human menopausal gonadotropin stimulation, the number of oocytes retrieved, the incidence of moderate or severe OHSS, the number of embryos available for transfer, implantation rates, clinical pregnancy rates, pregnancy loss rates, ectopic pregnancy rates, pregnancy and neonatal complications, and congenital anomalies. The necessary sample size for this trial was estimated as 392 participants, with 196 participants in each group. Intention-to-treat analysis was used in processing our experimental data.

ETHICS AND DISSEMINATION

This study was approved by the Institutional Review Board of the hospital (2016-133-T82). The trial will be conducted according to the principles of the World Medical Association's Declaration of Helsinki and in accordance with Good Clinical Practice standards. The findings of this trial will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTRIPR16009580.

Dynorphin and GABAA Receptor Signaling Contribute to Progesterone's Inhibition of the LH Surge in Female Mice

Progesterone can block estrogen-induced luteinising hormone (LH) surge secretion and can be used clinically to prevent premature LH surges. The blocking effect of progesterone on the LH surge is mediated through its receptor in the anteroventral periventricular nucleus (AVPV) of the hypothalamus. However, the underlying mechanisms are unclear. The preovulatory LH surge induced by estrogen is preceded by a significant reduction in hypothalamic dynorphin and gamma-aminobutyric acid (GABA) release. To test the detailed roles of dynorphin and GABA in an LH surge blockade by progesterone, ovariectomized and 17β-estradiol capsule-implanted (OVX/E2) mice received simultaneous injections of estradiol benzoate (EB) and progesterone (P) or vehicle for 2 consecutive days. The LH level was monitored from 2:30 pm to 8:30 pm at 30-minute intervals. Progesterone coadministration resulted in the LH surge blockade. A continuous microinfusion of the dynorphin receptor antagonist nor-BNI or GABAA receptor antagonist bicuculline into the AVPV from 3:00 pm to 7:00 pm reversed the progesterone-mediated blockade of the LH surge in 7 of 9 and 6 of 10 mice, respectively. In addition, these LH surges started much earlier than the surge induced by estrogen alone. However, 5 of 7 progesterone-treated mice did not show LH surge secretion after microinfusion with the GABAB receptor antagonist CGP-35348. Additionally, peripheral administration of kisspeptin-54 promotes LH surge-like release in progesterone treated mice. These results demonstrated that the progesterone-mediated suppression of the LH surge is mediated by an increase in dynorphin and GABAA receptor signaling acting though kisspeptin neurons in the AVPV of the hypothalamus in female mice.

Optimal Ovulation Trigger-Oocyte Pickup Interval in Progestin-Primed Ovarian Stimulation Protocol: A Retrospective Study Using Propensity Score Matching

Background: To investigate the optimal ovulation trigger-oocyte pickup (OPU) interval of a progestin-primed ovarian stimulation (PPOS) protocol. Method: Patients with normal ovarian reserve in their first PPOS OPU cycle were enrolled in this retrospective cohort study between July 2013 and April 2018. This retrospective cohort study included two parts. In part I, we studied the regression trend of mature oocyte rate, implantation rate, and live birth rate within the whole ovulation trigger-OPU interval of 7,258 patients. To homogenize some clinical characters that were key regulators of OPU time, in part II, we used propensity score matching to auto-select patients among trigger-OPU interval group 1 (35.6-36.4 h), group 2 (36.4-37.1 h), and group 3 (37.1-37.8 h) and analyzed clinical outcomes. Results: Study part I showed that the whole ovulation trigger-OPU interval (33-39.5 h) of PPOS protocol had a trend of a high mature oocyte rate (>80%), increasing implantation rate, and high live birth rate. Propensity score matching of patients with homogeneous clinical characteristics further indicated that the trigger-OPU interval within groups 2 and 3 (36.4-37.8 h) had significantly higher mature oocyte rates (84.54% vs. 84.60% vs. 82.34%, P = 0.002) and implantation rates (34.17% vs. 34.37% vs. 29.61%, P < 0.05) than group 1. The same tend was observed in the live birth rate. Conclusions: The ovulation trigger-OPU interval of 36.4-37.8 h is optimal for most patients using a PPOS protocol.

Progestin vs. Gonadotropin-Releasing Hormone Antagonist for the Prevention of Premature Luteinizing Hormone Surges in Poor Responders Undergoing in vitro Fertilization Treatment: A Randomized Controlled Trial

Objective: Progestin was recently used as an alternative of gonadotropin-releasing hormone (GnRH) analog for preventing premature luteinizing hormone (LH) surge with the aid of vitrification techniques, however, limited data were available about the potential of progestin in poor responders undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment. We performed a randomized parallel controlled trial to investigate the difference of progestin and GnRH antagonist in poor responders. Methods: A total of 340 poor responders who met with Bologna criteria were randomly allocated into the progestin-primed ovarian stimulation (PPOS) group and GnRH antagonist group. Fresh embryo transfer was preferred in the GnRH antagonist group and freeze-all was performed in the PPOS group. The primary outcome was the incidence of premature LH surge, secondary outcomes were the number of retrieved oocytes, the number of viable embryos and the pregnancy outcomes. Results: The results showed that the incidence of premature LH surge in PPOS group was lower than that in antagonist group (0 vs. 5.88%, P < 0.05). In PPOS group, the average numbers of oocytes and viable embryos were comparable to those in GnRH antagonist group (3.7 ± 2.6 vs. 3.4 ± 2.4; 1.6 ± 1.7 vs. 1.4 ± 1.3, P > 0.05), the live birth rate was similar between the two groups (21.8 vs. 18.2%, RR 1.25 (95% confidence interval 0.73, 2.13), P > 0.05). Conclusions: The study demonstrated that PPOS had a more robust control for preventing premature LH rise than GnRH antagonist in poor responders, but PPOS in combination with freeze-all did not significantly increase the probability of pregnancy than GnRH antagonist protocol for poor responders.

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.

Kisspeptin system in ovariectomized mice: Estradiol and progesterone regulation

The kisspeptin system is clustered in two main groups of cell bodies (the periventricular region, RP3V and the arcuate nucleus, ARC) that send fibers mainly to the GnRH neurons and in a few other locations, including the paraventricular nucleus, PVN. In physiological conditions, gonadal hormones modulate the kisspeptin system with expression changes according to different phases of the estrous cycle: the highest being in estrus phase in RP3V and PVN (positive feedback), and in ARC during the diestrus phase (negative feedback). In this work we wanted to study these hormonal fluctuations during the estrous cycle, investigating the role played by progesterone (P) or estradiol (E₂), alone or together, on the kisspeptin system. Gonadectomized CD1 female mice were treated with P, E₂ or both (E₂ + P), following a timing of administration that emulates the different phases of estrous cycle, for two cycles of 4 days. As expected, the two cell groups were differentially affected by E₂; the RP3V group was positively influenced by E₂ (alone or with the P), whereas in the ARC the administration of E₂ did not affect the system. However P (alone) induced a rise in the kisspeptin immunoreactivity. All the treatments significantly affected the kisspeptin innervation of the PVN, with regional differences, suggesting that these fibers arrive from both RP3V and ARC nuclei.

Progestin-primed ovarian stimulation with or without clomiphene citrate supplementation in normal ovulatory women undergoing in vitro fertilization/intracytoplasmic sperm injection: A prospective randomized controlled trial

OBJECTIVE

To compare the endocrinological profiles, cycle characteristics and pregnancy outcomes of progestin-primed ovarian stimulation (PPOS) with or without clomiphene citrate (CC) supplementation in normal ovulatory women undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

DESIGN

Prospective randomized controlled study.

PATIENT(S)

A total of 320 infertile women undergoing IVF/ICSI. Medroxyprogesterone acetate (MPA) and human menopausal gonadotropin (hMG) were simultaneously administered on menstrual cycle day 3. The women were randomized into 2 equal groups with or without CC supplementation.

MEASURES

The primary outcome measure was the percentage of women with profound pituitary suppression (luteinizing hormone [LH] <1.0 IU/L on the trigger day). The secondary outcomes were endocrinological profiles, cycle characteristics and pregnancy outcomes.

RESULTS

The percentage of women with profound pituitary suppression was significantly lower in the study group (hMG + MPA + CC) than in the control group (hMG + MPA) (1.9% vs 33.1%, P < .001). The mean LH level during controlled ovarian stimulation (COS) was higher in the study group than in the control group (P < .001), but none of the patients in either group exhibited a premature LH surge. The doses of Gn in the study group were significantly lower than those in the control group (1334.06 ± 212.53 IU vs 1488.28 ± 325.08 IU, P < .001). The number of oocytes retrieved was similar between the 2 groups (10.03 ± 5.97 vs 10.34 ± 7.52, P > .05). No significant differences were observed in either the number of viable embryos or the pregnancy outcomes between the 2 groups.

CONCLUSION(S)

Clomiphene citrate is an effective adjuvant to alleviate pituitary suppression in the PPOS protocol; however, it has no impact on clinical outcomes.

Neonatal outcomes and congenital malformations in children born after human menopausal gonadotropin and medroxyprogesterone acetate treatment cycles

PURPOSE

To investigate neonatal outcomes and congenital malformations in children born after in vitro fertilization (IVF) and vitrified embryo transfer cycles using human menopausal gonadotrophin and medroxyprogesterone acetate (hMG + MPA) treatment.

METHODS

We performed a retrospective cohort study including 4596 live born babies. During January 2014-June 2016, children born after either hMG + MPA treatment, gonadotropin releasing hormone agonist short protocol, or mild ovarian stimulation were included. The main outcome measures were neonatal outcomes and congenital malformations.

RESULTS

Neonatal outcomes both for singletons and twins such as mean birth weight and length, gestational age, the frequency of preterm birth were comparable between groups. Rate of stillbirth and perinatal death were also similar. No significant differences were found in the overall incidence of congenital malformations between the three groups. Multivariable logistic regression indicated that hMG + MPA regimen did not significantly increase the risk of congenital malformations compared with short protocol and mild ovarian stimulation, with adjusted odds ratio of 1.22 [95% confidence interval (CI) 0.61-2.44] and 1.38 (CI 0.65-2.93), respectively, after adjusting for confounding factors.

CONCLUSIONS

Our data suggested that compared with conventional ovarian stimulations, hMG + MPA treatment neither compromised neonatal outcomes of IVF newborns, nor did increase the prevalence of congenital malformations.

Hypothalamic effects of progesterone on regulation of the pulsatile and surge release of luteinising hormone in female rats

Progesterone can block the oestradiol-induced GnRH/LH surge and inhibit LH pulse frequency. Recent studies reported that progesterone prevented premature LH surges during ovarian hyperstimulation in women. As the most potent stimulator of GnRH/LH release, kisspeptin is believed to mediate the positive and negative feedback effects of oestradiol in the hypothalamic anteroventral periventricular (AVPV) and arcuate (ARC) nuclei, while the region-specific role of progesterone receptors in these nuclei remains unknown. This study examined the hypothesis that progesterone inhibits LH surge and pulsatile secretion via its receptor in the ARC and/or AVPV nuclei. Adult female rats received a single injection of pregnant mare serum gonadotropin followed by progesterone or vehicle. Progesterone administration resulted in a significant prolongation of the oestrous cycle and blockade of LH surge. However, microinjection of the progesterone receptor antagonist, RU486, into the AVPV reversed the prolonged cycle length and rescued the progesterone blockade LH surge, while RU486 into the ARC shortened LH pulse interval in the progesterone treated rats. These results demonstrated that progesterone's inhibitory effect on the GnRH/LH surge and pulsatile secretion is mediated by its receptor in the kisspeptin enriched hypothalamic AVPV and ARC respectively, which are essential for progesterone regulation of oestrous cyclicity in rats.

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.

Effects of progesterone and testosterone on cocaine self-administration and cocaine discrimination by female rhesus monkeys

The neuroactive steroid hormone progesterone attenuates cocaine's abuse-related effects in women and in rodents under some conditions, but the effects of testosterone are unknown. We compared the acute effects of progesterone (0.1, 0.2, and 0.3 mg/kg, intramuscularly (i.m.)), testosterone (0.001, 0.003, and 0.01 mg/kg, i.m.), and placebo on cocaine self-administration and cocaine discrimination dose-effect curves in female rhesus monkeys. Cocaine self-administration (0.03 mg/kg per inj.) was maintained on a fixed ratio 30 schedule of reinforcement, and monkeys had unlimited access to cocaine for 2 h each day. Cocaine doses were administered in an irregular order during each dose-effect curve determination, and the same dose order was used in each subject in all treatment conditions. Blood samples for hormone analysis were collected at the end of each test session. Banana-flavored food pellets (1 g) were also available in three 1-h daily sessions. In drug discrimination studies, the effects of pretreatment with progesterone (0.032-0.32 mg/kg, i.m.) and testosterone (0.001-0.01 mg/kg, i.m.) on the discriminative stimulus effects of cocaine (0.18 mg/kg, i.m.) were examined. Progesterone and testosterone did not alter cocaine discrimination, and did not substitute for cocaine. In contrast, progesterone and testosterone each significantly decreased cocaine self-administration, and produced a downward and rightward shift in the cocaine self-administration dose-effect curve. These findings are concordant with clinical reports that progesterone administration may decrease ratings of positive subjective effects of cocaine in women, and suggest the possible value of neuroactive steroid hormones for the treatment of cocaine abuse and reduction of risk for relapse.

Effects of estradiol on cocaine self-administration and cocaine discrimination by female rhesus monkeys

The ovarian steroid hormone, estradiol, enhances the reinforcing and locomotor activating effects of cocaine in rodents under some conditions. The present study evaluated the acute effects of estradiol benzoate (E(2)beta) on cocaine self-administration and cocaine discrimination in female rhesus monkeys. Cocaine self-administration (0.10 mg/kg/inj., i.v.) was maintained on a fixed-ratio (FR) 30 schedule of reinforcement, and monkeys had access to cocaine during one 2-h session each day. E(2)beta in a cyclodextrin vehicle (0.00001-0.01 mg/kg, i.m.) was administered 30 min before test sessions conducted twice each week. Cocaine doses were administered in an irregular order during each dose-effect curve determination (0.001-0.3 mg/kg/inj.). Blood samples were collected after test sessions to determine 17beta-estradiol levels. Banana-flavored food pellets were available on an FR 30 schedule in three 1-h sessions each day. Five monkeys were trained to discriminate cocaine (0.18 mg/kg, i.m.) from saline in a two-key food-reinforced procedure, and the effects of pretreatment with E(2)beta in cyclodextrin and in sesame oil were studied. Acute administration of E(2)beta did not consistently alter the cocaine self-administration or drug discrimination dose-effect curves in comparison to saline control treatment. Females also did not self-administer E(2)beta (0.00001-0.10 mg/kg, i.v.) above saline levels. Finally, E(2)beta (0.0001-0.01 mg/kg, i.m.) did not substitute for cocaine in monkeys trained to discriminate cocaine from saline. Taken together, these data suggest that over the dose range studied, estradiol administration does not consistently alter the abuse-related effects of cocaine in female rhesus monkeys.

Facilitation or inhibition of the oestradiol-induced gonadotrophin surge in the immature female rat by progesterone: effects on pituitary responsiveness to gonadotrophin-releasing hormone (GnRH), GnRH self-priming and pituitary mRNAs for the progesterone receptor A and B isoforms

Progesterone can either facilitate or inhibit the oestradiol (E(2))-induced gonadotrophin surge. We have previously developed immature female rat models to characterise and investigate the mechanisms of progesterone inhibition or facilitation. The aim of the present study was to determine the role of pituitary responsiveness to gonadotrophin-releasing hormone (GnRH) and GnRH self-priming under conditions of progesterone-facilitation and progesterone-inhibition, and whether the underlying mechanisms reflect changes in mRNAs encoding the A and B isoforms of the progesterone receptor (PR) in the pituitary gland. Pituitary responsiveness to GnRH, determined by measuring the luteinising hormone (LH) response to one i.v. injection of GnRH, was decreased by 60-80% (P < 0.001) in the progesterone-inhibition model. GnRH self-priming, estimated as the increment in the LH response to the second of two injections of GnRH separated by 60 min, was also significantly reduced (P < 0.05) in this model. In the progesterone-facilitation model, the LH response to GnRH injection was increased 2.5-3-fold (P < 0.05), an effect suppressed by the progesterone receptor antagonist, mifepristone. Progesterone-facilitation of LH release and increased pituitary responsiveness to GnRH were blocked by sheep anti-GnRH serum injected i.v. immediately after insertion of progesterone implants. The PR-B mRNA isoform, measured by solution hybridisation/RNase protection assay, was the predominant form in the pituitary of the immature female rat. PR-B was increased by E(2) and decreased by progesterone in both models. Thus, in immature female rats, progesterone-inhibition of the E(2)-induced LH surge is due to significant reduction in pituitary responsiveness to GnRH as well as in the magnitude of GnRH self-priming. Progesterone-facilitation of the E(2)-induced LH surge is due to increased pituitary responsiveness to GnRH, which is mediated by PR, and depends on endogenous GnRH release. The differences between progesterone-facilitation and progesterone-inhibition are not due to differences in regulation of pituitary PR-B mRNA.

Sex and menstrual cycle effects on progressive ratio measures of cocaine self-administration in cynomolgus monkeys

Fluctuations in ovarian steroid hormones across the menstrual/estrous cycle influence the abuse-related effects of acute cocaine administration in women and chronic cocaine self-administration in rodents, but there have been no comparable studies in non-human primates. The interactions among sex, menstrual cycle phase, and cocaine self-administration (0.0032, 0.01, and 0.032 mg/kg/injection (inj)) under a progressive ratio schedule were investigated in four female and two male cynomolgus monkeys. Females were given unrestricted access to cocaine across 54 menstrual cycles, and males were studied over 23 pseudo-cycles of 30 days duration. Ovulatory cycles were defined by luteal phase elevations in progesterone and 44 cycles were ovulatory. During ovulatory menstrual cycles, females reached significantly higher progressive ratio break points than males at all three unit doses of cocaine (P<0.001). During anovulatory cycles, females also reached significantly higher break points than males for 0.032 mg/kg/inj cocaine (P<0.01). Progressive ratio break points for cocaine (0.01 and 0.032 mg/kg/inj) did not vary significantly as a function of ovarian steroid hormone levels during the follicular and the luteal phase of ovulatory menstrual cycles, or during anovulatory cycles. Progressive ratio break points for 0.0032 mg/kg/inj cocaine were significantly higher during the follicular phase than during the late luteal phase (P<0.05-0.001). There were no systematic changes in progressive ratio break points in male pseudo-cycles. Significant cocaine dose-related sex differences were observed, but no consistent changes in cocaine self-administration as a function of menstrual cycle phase, or levels of estradiol and progesterone, were detected in female cynomolgus monkeys.

Effect of gonadectomy and gonadal hormone replacement on cocaine self-administration in female and male rats

Both sex and gonadal steroid hormones may influence the abuse-related behavioral effects of cocaine under some conditions, but there is considerable inconsistency in the literature. In the present study, rats were trained under a fixed ratio (FR) 5 schedule of food presentation and were then allowed to self-administer cocaine (1.0 mg/kg/injection) until behavior stabilized. Subsequently, complete dose-effect functions for cocaine self-administration (0.032-3.2 mg/kg/injection) were determined in female and male rats before and after gonadectomy, and in gonadectomized female and male rats before and during chronic treatment with estradiol or testosterone, respectively. Sex, gonadectomy, and gonadal hormones did not alter the shape or position of dose-effect functions for cocaine self-administration. These results suggest that sex, estrogen, and testosterone levels are not critical determinants of cocaine's reinforcing effects in rats under these conditions. This study differed from earlier studies in that complete dose-effect functions for cocaine were determined. These findings suggest that the behavioral training history, the unit dose of cocaine, and the schedule of reinforcement are important variables in studies of sex and gonadal hormone effects on cocaine self-administration.

Progesterone blocks the estradiol-stimulated luteinizing hormone surge by disrupting activation in response to a stimulatory estradiol signal in the ewe

The preovulatory surges of GnRH and LH are activated by increased concentrations of circulating estradiol, but ovulation is blocked when progesterone concentrations are elevated. Although it is has been shown that this action of progesterone is due to a central inhibition of the GnRH surge, the mechanisms that underlie the blockade of the GnRH surge are poorly understood. In this study we investigated whether progesterone can block the estradiol-dependent activation stage of the GnRH surge induction process, and thus prevent expression of the LH surge. The results demonstrated that exposure to progesterone for half or the full duration of the activation stage can prevent the stimulation of LH surges by estradiol (experiment 1), whereas exposure to progesterone midway though a period of estradiol exposure, which in itself is sufficient to activate the surge, did not block the LH surge (experiment 2). These results suggest that progesterone 1) disrupts activation of the surge induction system in response to a stimulatory estradiol signal and 2) does not compromise the ability of animals to respond to a stimulatory estradiol signal applied immediately after progesterone exposure. Because the disruptive effects of activated progesterone in response to estradiol are rapid but transient, it may be that progesterone directly interferes with the activation of estradiol-responsive neural systems to block the GnRH/LH surge.

Progesterone receptors as neuroendocrine integrators

Intracellular progesterone receptors (PRs) are ligand-inducible transcription factors that mediate the majority of the effects of progesterone (P) on neuroendocrine functions. During the past decade, evidence has accumulated which suggest that PRs can also be activated independently of P, by signals propagated through membrane-bound receptors to the interior of cells. The activation of PRs by this type of "cross-talk" mechanism has been implicated in the physiological regulation of several important neuroendocrine processes, including estrous behavior and periovulatory hormone secretions. We review evidence that both ligand-dependent and ligand-independent activation of PRs occurs in central neurons and in anterior pituitary cells and that the convergence and summation of these signals at the PR serves to integrate neural and endocrine signals which direct several critically important neuroendocrine processes. An integrative function for PRs is reviewed in several physiological contexts, including the display of lordosis behavior in female rodents, the neurosecretion of gonadotropin-releasing hormone surges, secretion of preovulatory gonadotropin surges, and release of periovulatory follicle stimulating hormone surges. The weight of evidence indicates that cross talk at the intracellular PR is an essential component of the integrative mechanisms that direct each of these neuroendocrine events. The recurrence of PR's integrative actions in several different physiological contexts suggests that other intracellular steroid receptors similarly function as integrators of neural and endocrine signals in other neuroendocrine processes.

Unmasking the progesterone receptor in the preoptic area and hypothalamus of the ewe: no colocalization with gonadotropin-releasing neurons

Progesterone powerfully inhibits GnRH secretion in ewes, as in other species, but the neural mechanisms underlying this effect remain poorly understood. Visualization of the neural ovine progesterone receptor has proved elusive but, using a high temperature antigen unmasking technique, the progesterone receptor was revealed in the ewe brain. Progesterone receptors were located in the preoptic-hypothalamic continuum, especially in the preoptic area, ventrolateral region of the ventromedial nucleus and the arcuate nucleus. This study also suggests that the inhibitory action of progesterone on GnRH release is not transduced directly through the GnRH neurons as a single GnRH perikaryon of 732 was immunoreactive for the progesterone receptor.

Duration and amplitude of the luteal phase progesterone increment times the estradiol-induced luteinizing hormone surge in ewes

Progesterone (P) powerfully inhibits the neuroendocrine reproductive axis, but the mechanisms and site or sites of action of this steroid remain poorly understood. Progesterone exposure during the luteal phase also alters the responsiveness of the hypothalamus to increased concentrations of estrogen (E) during the follicular phase. Using an ovariectomized ovine follicular phase model, we investigated whether the amplitude and duration of the luteal phase increase in circulating P affects the E-induced surge in LH. Treatment of ewes for 10 days with two, one, or half an intravaginal P-releasing implant or with an empty implant demonstrated that P concentrations significantly (P: < 0.0001) delayed the time to surge onset upon exposure to an equal concentration of E. This delay was not due to a time-related difference in responsiveness to E after P clearance because the time of surge onset was not different when E treatment began 6, 12, or 24 h after the withdrawal of two P implants that had been present for 10 days. The final study demonstrated that the duration of P before treatment (5, 10, or 30 days) significantly (P: < 0.0001) delayed the responsiveness of the estradiol-dependent surge-generating system. There was no effect on surge amplitude or duration in any experiment. Thus, the amplitude and duration of exposure to luteal phase P significantly affect the neural elements targeted by E to induce the preovulatory LH surge.

The progesterone blockade of the luteinizing hormone surge is overcome by RU486

Progesterone can prevent the oestrogen-induced and spontaneous preovulatory luteinizing hormone (LH) surges but the mechanisms underlying this effect remain poorly understood. Using a follicular phase ovariectomised (OVX) ewe model and by elevating progesterone in the presence of oestrogen to inhibit the LH surge, we investigated whether the progesterone receptor antagonist, RU486, could block the inhibitory effects of progesterone. Accordingly, intravaginal progesterone implants were inserted into OVX Ile-de-France ewes (n = 18), bearing 10 mm Silastic 17beta-oestradiol implants. Ten days later, the progesterone implants were removed, whereupon new implants were inserted immediately into 12 ewes: six of which were also injected with 100 mg RU486 dissolved in 10 mL vehicle (10% alcohol in peanut oil) and six received vehicle only. The remaining six ewes were injected with vehicle only. RU486 and vehicle injections were made again 12 and 24 h later. After the last injection, oestrogen concentrations were raised to peak follicular phase levels in all ewes by subcutaneous insertion of four 3-cm 17beta-oestradiol implants. Blood samples were collected every 2 h for 40 h starting 9 h after the insertion of the oestrogen implants. As expected, the six ewes treated only with oestradiol had a LH surge whereas no ewes given the implants in the presence of progesterone surged. RU486 completely blocked the inhibitory effect of progesterone. There were no differences in the time of LH surge onset, duration over which LH levels remained above their half-maximal concentration or magnitude of the LH surge between the two groups showing surges. Our study suggests strongly that the progesterone-mediated blockade of the ovine oestrogen-induced LH surge is not through allopregnanolone activation of the GABA(A) receptor. Rather, our study demonstrates that this effect is transduced by the classic nuclear progesterone receptor.

The negative feedback actions of progesterone on gonadotropin-releasing hormone secretion are transduced by the classical progesterone receptor

Progesterone (P) powerfully inhibits gonadotropin-releasing hormone (GnRH) secretion in ewes, as in other species, but the neural mechanisms underlying this effect remain poorly understood. Using an estrogen (E)-free ovine model, we investigated the immediate GnRH and luteinizing hormone (LH) response to acute manipulations of circulating P concentrations and whether this response was mediated by the nuclear P receptor. Simultaneous hypophyseal portal and jugular blood samples were collected over 36 hr: 0-12 hr, in the presence of exogenous P (P treatment begun 8 days earlier); 12-24 hr, P implant removed; 24-36 hr, P implant reinserted. P removal caused a significant rapid increase in the GnRH pulse frequency, which was detectable within two pulses (175 min). P insertion suppressed the GnRH pulse frequency even faster: the effect detectable within one pulse (49 min). LH pulsatility was modulated identically. The next two experiments demonstrated that these effects of P are mediated by the nuclear P receptor since intracerebroventricularly infused P suppressed LH release but 3alpha-hydroxy-5alpha-pregnan-20-one, which operates through the type A gamma-aminobutyric acid receptor, was without effect and pretreatment with the P-receptor antagonist RU486 blocked the ability of P to inhibit LH. Our final study showed that P exerts its acute suppression of GnRH through an E-dependent system because the effects of P on LH secretion, lost after long-term E deprivation, are restored after 2 weeks of E treatment. Thus we demonstrate that P acutely inhibits GnRH through an E-dependent nuclear P-receptor system.

Inhibition of sexual behaviour and the luteinizing hormone surge by intracerebral progesterone implants in the female sheep

In female sheep, progesterone blocks the induction by oestradiol of both sexual behaviour and the pre-ovulatory surges of gonadotrophin releasing hormone (GnRH) and luteinising hormone (LH). However, the central sites of action of progesterone remain poorly defined, so we attempted to locate them by implanting progesterone intracerebrally in ovariectomised ewes treated with exogenous steroids to induce oestrous behaviour and the LH surge. Single bilateral implants or a double bilateral implants filled with progesterone or cholesterol were placed in the ventromedial hypothalamus (VMH) or the preoptic area (POA). Control ewes were not implanted. To determine the inhibitory capacity of the central progesterone implants, ewes received an injection (i.m.) of 8 micrograms or 16 micrograms of oestradiol. The single bilateral implants of progesterone failed to block oestrous behaviour and the LH surge induced by 8 micrograms of oestradiol. Double bilateral progesterone implants in the VMH blocked the sexual behaviour (P < 0.05) and the LH surge (P < 0.05), but implants in the POA blocked only sexual receptivity (P < 0.05). No changes were observed after central implantation of cholesterol. Our results support the hypothesis that progesterone acts centrally in the VMH and the POA to inhibit the induction of LH surge and sexual behaviour by oestradiol.

Progesterone effects on the acquisition of conditioned avoidance responses an other motoric behaviors in intact and ovariectomized rats

This study demonstrates a significant impairment in the acquisition of conditioned avoidance responses in female rats during their estrus phase. Progesterone (PROG 5 mg) injected 6 h prior to the test, significantly enhanced the performance exhibited by rats at estrus, but not at diestrus. In ovariectomized rats, the acquisition of conditioned avoidance responses was similar to the exhibited during diestrus and this behavior was depressed by a single dose of estradiol benzoate (EB 2 micrograms) injected 48 h prior to the test. PROG antagonized the avoidance depression induced by EB, but it was not able to induce changes in the acquisition of conditioned avoidance response in ovariectomized rats without EB pretreatment. Estradiol appears to be the principal ovarian steroid modulating the acquisition of an avoidance task, whereas PROG seems to have a secondary role in this behavior, regulating the actions of estradiol on the brain. PROG failed to induce consistent changes in some spontaneous motor behaviors in intact and ovariectomized rats.

Vaginal progesterone administration in physiological doses normalizes raised luteinizing hormone levels in patients with polycystic ovarian syndrome

A raised luteinizing hormone (LH) level is a typical finding in the polycystic ovarian syndrome (PCOS). This inappropriate elevation of LH is thought to interfere with normal follicular development and ovulation. The resulting chronic anovulation is associated with the absence of the luteal phase increase in secretion of progesterone and inhibin. Progesterone can exert both a positive and negative feedback action on LH secretion, but inhibition is thought to occur following prolonged exposure to progesterone. Therefore, the aim of this study was to see if exogenously administered progesterone in physiological doses would normalize circulating LH concentrations in patients with PCOS. Vaginal progesterone was administered twice daily in a dose of 100 mg, at 12 h intervals, to ten women with PCOS. Serum samples were taken on alternate days for radioimmunoassay of follicle stimulating hormone (FSH), LH, estradiol, progesterone and inhibin. To determine the effect of progesterone on LH secretory dynamics in PCOS, LH pulse studies were carried out prior to treatment, and on day 10 of progesterone administration in four of the ten subjects. Mean serum progesterone concentrations reached 51 nmol/l by 4 days after exogenous progesterone treatment, and remained in the mid-luteal phase range, as established in 12 normal cycles, during the use of the vaginal suppository. The mean serum LH concentration had fallen significantly (p < or = 0.01) after 8 days of treatment, and continued to fall progressively until the end of progesterone administration. Serum LH concentrations had fallen into the normal follicular phase range by 14 days (mean 5.5, range 3.4-10.9 IU/l; normal follicular phase range 1.8-10.0 IU/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of progesterone administration on follicle-stimulating hormone and prolactin release in estrogen treated eugonadal adult men

In order to investigate the modulatory effect of steroids on FSH secretion in vivo, we studied 16 human males, aged 51-81 years, affected by prostatic carcinoma. They were given estradiol or E2 plus progesterone (P), added at different times during E2 treatment. Daily blood samples were collected in order to determine LH, FSH, and PRL levels; moreover, blood samples were collected at 2 h intervals for 12 h on the day of P administration. We observed the expected biphasic effect on LH secretion, whereas daily basal FSH levels, during E2 treatment, decreased gradually and progressively from the first day until the end of the study. FSH levels exhibited, after P administration, wide fluctuations, with peak levels observed from 2 to 6 h after P in 4 of 6 patients studied (at 72 h during E2 treatment). A clear trend toward FSH increase was also observed in 3 out of 5 patients in whom P was administrated 96 h after starting E2 administration. In this case, FSH increases were delayed, becoming evident between 8th and 10th h after P injection. Finally, during E2 administration basal PRL levels showed a progressive increase, which was significant in all three groups. In conclusion, these data confirm the biphasic effects of estrogen administration on LH secretion in eugonadal adult human males; while estrogens alone showed an inhibitory effect on FSH secretion, the addition of P induced also a positive action, resulting in a clear FSH peak in some patients tested. The time course of E2 and P administration seems to be critical for the hormone response pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Endocrine responses to long-term administration of the antiprogesterone RU486 in patients with pelvic endometriosis

OBJECTIVE

To examine endocrine and clinical responses to long-term administration of RU486 in patients with endometriosis.

DESIGN

Prospective open trial.

SETTING

Faculty practice of the authors.

PATIENTS, PARTICIPANTS

Six normally cycling women with endometriosis were recruited.

INTERVENTIONS

Subjects received RU486 100 mg/d for 3 months.

MAIN OUTCOME MEASURE(S)

Hormonal changes during RU486 were compared with control data obtained in the preceding cycle during the early follicular phase. Clinical responses were determined by patient assessment and second-look laparoscopy.

RESULTS

All women became amenorrheic, and daily urinary levels of ovarian steroid metabolites remained acyclic. Mean luteinizing hormone (LH) (P less than 0.02) and LH pulse amplitude (P less than 0.05) were increased without changes in LH pulse frequency. An antiglucocorticoid effect was demonstrated by an increase in serum cortisol (P less than 0.01) and adrenocorticotropic hormone (P less than 0.05) levels. Treatment resulted in an improvement in pelvic pain in all subjects without significant change in the extent of disease as evaluated by follow-up laparoscopy.

CONCLUSIONS

Daily administration of RU486 results in acyclic ovarian function and improvement in the subjective painful symptoms of endometriosis.

Dose-dependent effects of chronic treatment with estradiol or progesterone on LH secretion in ovariectomized rats

Ovariectomized (OVX) Sprague-Dawley rats bearing atrial cannulae were implanted subcutaneously with fused pellets containing estradiol (E2) or progesterone (P4). Variable doses of E2 (0.1, 0.5, 1 and 5%) or P4 (10, 50, 75, 100%) were achieved by varying the ratio of the hormone to cholesterol (CHOL) in the pellet. Control groups were treated with CHOL containing pellets. Blood samples were collected in the morning and afternoon the day before and 1, 2, 5, 8, 11 and 14 days after pellet implantation. The concentrations of E2, P4 and LH were measured by RIA. Throughout the sampling period, plasma concentrations of both steroids were proportional to pellet composition. On days 1 and 2, high concentrations of E2 and P4 in plasma were obtained, but between days 5 and 14 stable levels at E2 and P4 were observed. The effectiveness of chronic replacement with E2 and P4 on the negative feedback on LH secretion was assessed from morning samples and positive feedback on LH from afternoon samples. E2 implants suppressed the morning LH levels in plasma in a time and dose-dependent manner. The afternoon concentrations of LH were significantly elevated on each sampling day, except for day 1. P4 pellets had no effect on morning-afternoon difference in LH level, but low doses suppressed LH shortly after the implantation and high doses suppressed LH level after the 8th day of implantation. These results indicate that fused pellets of E2 and P4 are effective in chronically maintaining plasma E2 and P4 at levels observed during various normal and pathological reproductive states. Further, these studies indicate that E2 can stimulate afternoon hypersecretion of LH for at least 14 days in ovariectomized rats.

Progesterone alters the pituitary response to luteinizing hormone releasing hormone in postmenopausal women previously treated with estradiol

The effect of luteinizing hormone-releasing hormone (LHRH) on LH release was studied in 5 menopausal women injected with progesterone. Each patient received 2 x 100 micrograms doses of LHRH administered intravenously 120 minutes apart under the following conditions: without any previous treatment (test 1); 16 hours after intramuscular injection of 10 mg progesterone (test 2); after 3-4 weeks of oral treatment with 50 micrograms/day of ethinyl estradiol (EE2) (test 3); 16 hours after intramuscular injection of 10 mg progesterone following treatment with 50 micrograms/day oral EE2 for 3-4 weeks (test 4). The interval between tests was at least 1 month. Progesterone decreased the total plasma hormonal increment (PHIt) of hypogonadal women, with a reduction in plasma hormonal increment both after the 1st stimulus (PHI1) and after the 2nd stimulus (PHI2), whereas estradiol increased PHIt, mainly due to an increase of PHI2. The administration of progesterone to hypogonadal women previously treated with EE2 maintained the increased PHIt caused by the latter, but not owing to a greater increase in PHI1.

Gonadal and pituitary responses to progesterone antagonist ZK 98.299 during the follicular phase of the menstrual cycle in bonnet monkeys

ZK 98.299 is a potent progesterone antagonist. Its effects on folliculogenesis, bioactive LH, ovulation and menstrual cycle (m.c.) length were studied in adult bonnet monkeys. ZK 98.299 (20 mg/day) was administered s.c., once daily on days 5 to 15 of m.c., to ten animals. The pretreatment m.c. was of 26.5 days (25 to 28 days, mean with 95% confidence limits) and on treatment it was significantly (p less than 0.001) prolonged to 46.9 days (39 to 54 days). The anticipated midcycle rise in estradiol and bioactive LH levels was completely blocked in six and attenuated in three animals during the treatment period. However, the levels did not drop below the early follicular phase levels. In one animal (#90), though the cycle length was prolonged by 5 days the midcycle rise in estradiol and bioactive LH levels was observed during the treatment period and this animal had normal luteal function. Seven animals had delayed ovulation whereas, two had anovulatory treatment cycles. The rise in estradiol and bioactive LH levels, prior to ovulation in the treatment cycles, was compatible with the midcycle rise observed in the pretreatment cycles. Serum progesterone levels during the luteal phase of the treatment cycles were normal in six animals whereas, in two they were indicative of luteal insufficiency. In two animals, the treatment cycles were anovulatory. ZK 98.299 had no effect on the duration of menses. The post-treatment cycles were of normal duration. This study suggests that the administration of ZK 98.299 during the follicular phase blocks estradiol and bioactive LH release and terminates the follicular phase in most of the animals. The follicular phase is reinitiated after the treatment is stopped.

Integration of the effects of estradiol and progesterone in the modulation of gonadotropin secretion

Estradiol secreted by the maturing follicle is the primary trigger for the surge of gonadotropins leading to ovulation. Progesterone has stimulatory or inhibitory actions on this estrogen-induced gonadotropin surge depending upon the time and dose of administration. The administration of progesterone to immature ovariectomized rats primed with a low dose of estradiol induced a well-defined LH surge and prolonged FSH release, a pattern similar to the proestrus surge of gonadotropins. A physiological role of progesterone is indicated in the normal ovulatory process because a single injection of the progesterone antagonist RU 486 on the day of proestrus in the adult cycling rat and on the day of the gonadotropin surge in the pregnant mare's serum gonadotropin stimulated immature rat resulted in an attenuated gonadotropin surge and reduced the number of ova per ovulating rat. Progesterone administration brought about a rapid LHRH release and an decrease in nuclear accumulation of estrogen receptors in the anterior pituitary but not the hypothalamus. The progesterone effect was demonstrated in vitro in the uterus and anterior pituitary and appears to be confined to occupied estradiol nuclear receptors. In in vivo experiments the progesterone effect on estradiol nuclear receptors appeared to be of approximately 2-h duration, which coincided with the time period of progesterone nuclear receptor accumulation after a single injection of progesterone. During the period of progesterone effects on nuclear estrogen receptors, the ability of estrogens to induce progesterone receptors was impaired. Based on the above results, a model is proposed for the stimulatory and inhibitory effects of progesterone on gonadotropin secretion.

Relationships between the characteristics of endogenous luteinizing hormone surge and the degree of ovarian hyperstimulation during superovulation induction in women

Ovarian hyperstimulation was induced in 17 normally cycling women undergoing in-vitro fertilization (IVF) and embryo transfer with clomiphene (9 cycles), clomiphene followed by pulsatile hMG (12 cycles) or clomiphene followed by pulsatile FSH (11 cycles). Hyperstimulation was greater with the combined treatments than with clomiphene alone. In all 32 cycles an endogenous LH surge occurred. The peak values and the duration of the LH surge showed significant negative correlations with the plasma oestradiol levels, the number of the follicles and the total follicular fluid volume aspirated at laparoscopy. We suggest that during superovulation induction for IVF, the endogenous LH surge is attenuated by factors which are related to the degree of ovarian hyperstimulation.

Endogenous luteinizing hormone surge in women during induction of multiple follicular development with pulsatile follicle stimulating hormone

In this study nine consecutive normally cycling women undergoing in-vitro fertilization (IVF) were superovulated with clomiphene citrate followed by pulsatile 'pure' FSH injected s.c. via a pump (28 IU every 3 h). All women displayed an endogenous LH surge, which was markedly attenuated in most of the cases (peak value 44.5 +/- 5.9 U/l, duration 29.2 +/- 1.2 h, mean +/- SEM) as compared to spontaneous cycles. An increase in serum progesterone levels before the onset of the LH surge was seen in only one woman at a time when the LH values were low. During the LH surge serum progesterone levels increased significantly in all patients (12.7 +/- 1.90 nmol/l vs 4.74 +/- 1.57 nmol/l at the onset of the surge, mean +/- SEM, P less than 0.05) indicating follicular luteinization. Very high oestradiol levels in serum were found at the onset of the LH surge (7504 +/- 898 pmol/l, mean +/- SEM). Preovulatory oocytes were recovered from all women through a laparoscope 34-36 h after the beginning of the LH surge and embryos were replaced to them after IVF. One ongoing clinical pregnancy occurred. In contrast to results in monkeys, these results demonstrate for the first time that normally cycling women superovulated with clomiphene pulsatile 'pure' FSH will display an endogenous LH surge. Although the surge is attenuated implantation can occur.

The dynamic interaction between steroids and gonadotropins in the mammalian ovulatory cycle

The interrelationship between steroid hormone secretion and gonadotropin secretion during the human menstrual cycle is a set of complex interactions. The temporal relationship between estradiol and progesterone secretion, the preovulatory surge of gonadotropins and the time of ovulation, has been studied extensively. The median time interval between the first rise of estradiol, progesterone, LH and FSH, and ovulation has been estimated to be 82.5 hr, 7.8 hr, 32 hr and 21.1 hr, respectively. The median time interval between peak blood concentrations of estradiol, LH and FSH, and the time of ovulation is estimated to be 24, 16.5 and 15.3 hr. There is considerable individual variation in the above mentioned estimates. The rising levels of blood estradiol that are secreted by the maturing ovarian follicles appear to be the primary trigger for the surge of gonadotropins leading to ovulation. In the experimental animal, the estrogen effect takes place at the level of the hypothalamus in the release of LHRH and at the level of the pituitary in increasing its sensitivity to LHRH. There appears to be a good correlation between the nuclear translocation of occupied estrogen receptors in the hypothalamus and the pituitary and the manifestation of estrogen effects. In the human, a rise in progesterone begins to take place after the first rise in LH has occurred. Progesterone appears to have both a stimulatory and inhibitory effect on gonadotropin secretion in the experimental animal and the human. Thus it exerts a fine-tune modulatory influence of estrogen effects which include enhancement of the estradiol induced gonadotropin surge, and perhaps the initiation of the midcycle FSH surge in the human. The abrupt termination of the preovulatory gonadotropin surge is difficult to explain because the pituitary gland is not depleted of its gonadotropin content or its capacity to secrete gonadotropins. Preliminary results suggests that progesterone by exerting its inhibitory influence may be responsible for the termination of the gonadotropin surge. This hypothesis, however, needs careful confirmation. The effects of progesterone may be manifested at higher brain centers, the hypothalamus and the pituitary, and may involve not only the release of LHRH but also an alteration of the pulsatile pattern of release of LHRH. The recognition of these components, along with the presence and control of LHRH degrading enzymes in the hypothalamus and the pituitary, emphasize the complexity of the system and the need for further work to gain a better understanding of the steroidal regulation of gonadotropin secretion.

The effect of dydrogesterone on the mid-cycle gonadotrophin surge in regularly cycling women

The effect of dydrogesterone, a retro-progesterone on the spontaneous mid-cycle surge of gonadotrophin in regularly cycling women, was investigated. Blood samples were collected through two complete cycles in six subjects. The first untreated cycle acted as a control for the second cycle during which dydrogesterone (10 mg twice daily) was administered. The start of treatment ranged from day 1 (one subject), mid follicular phase (three subjects) to post-ovulation (two subjects). In all subjects where dydrogesterone was given before ovulation, the mid-cycle gonadotrophin surge was either abolished or markedly diminished. Despite this follicular growth occurred in all four subjects and subsequently luteinisation was observed in three. Dydrogesterone given after ovulation did not produce any alteration in endocrine profiles but menses was postponed in both subjects. Thus dydrogesterone can mimic the known blocking actions of progesterone on the mid-cycle gonadotrophin surge and can support a secretory endometrium for a limited period in the absence of endogenous progesterone.

Serum luteinizing hormone during ovulation induction with human menopausal gonadotropin for in vitro fertilization in normally menstruating women

Sixteen cycles in 14 normally menstruating women, stimulated with human menopausal gonadotropin in order to recruit more than one follicle for a successful in vitro fertilization process, were adequately monitored to identify the appearance of the spontaneous luteinizing hormone (LH) surge. Daily serum LH determinations, increased to every 4 hours in the presumptive preovulatory period, showed that in these women the endogenous estrogen-triggered LH midcycle peak did not occur at the expected time. It is hypothesized that the mechanism responsible for this suppression is a negative feedback mediated by an increased circulating protein with an inhibin-like action.