Gonadotropin-releasing hormone and its analogues

Porous silicon and silica carriers for delivery of peptide therapeutics

Peptides have gained tremendous popularity as biological therapeutic agents in recent years due to their favourable specificity, diversity of targets, well-established screening methods, ease of production, and lower cost. However, their poor physiological and storage stability, pharmacokinetics, and fast clearance have limited their clinical translation. Novel nanocarrier-based strategies have shown promise in overcoming these issues. In this direction, porous silicon (pSi) and mesoporous silica nanoparticles (MSNs) have been widely explored as potential carriers for the delivery of peptide therapeutics. These materials possess several advantages, including large surface areas, tunable pore sizes, and adjustable pore architectures, which make them attractive carriers for peptide delivery systems. In this review, we cover pSi and MSNs as drug carriers focusing on their use in peptide delivery. The review provides a brief overview of their fabrication, surface modification, and interesting properties that make them ideal peptide drug carriers. The review provides a systematic account of various studies that have utilised these unique porous carriers for peptide delivery describing significant in vitro and in vivo results. We have also provided a critical comparison of the two carriers in terms of their physicochemical properties and short-term and long-term biocompatibility. Lastly, we have concluded the review with our opinion of this field and identified key areas for future research for clinical translation of pSi and MSN-based peptide therapeutic formulations.

Timing of puberty suppression in transgender adolescents and sexual functioning after vaginoplasty

BACKGROUND

Sexual function in transgender adolescents after puberty suppression has been a topic of recent clinical and scientific questions.

AIM

This study aimed to explore the long-term effects of early treatment with puberty suppression on sexual functioning of transfeminine individuals after vaginoplasty.

METHODS

This retrospective cohort study included 37 transfeminine individuals treated with a gonadotropin-releasing hormone agonist (puberty suppression), estrogen, and vaginoplasty (penile inversion technique or intestinal vaginoplasty) at the Center of Expertise on Gender Dysphoria in Amsterdam, the Netherlands, between 2000 and 2016.

OUTCOMES

Experiences regarding sexual functioning and difficulties were assessed with a self-developed questionnaire ~1.5 years after genital gender-affirming surgery and compared between early (Tanner stage G2-3) and late (Tanner stage G4-5) treatment with puberty suppression.

RESULTS

Following surgery, 91% of transfeminine individuals was able to experience sexual desire, 86% experienced arousal, and 78% could attain an orgasm. Seventy-five percent of transfeminine individuals who had not experienced an orgasm pre-surgery were able to experience one post-surgery. Of all participants, 62% reported having tried penile-vaginal intercourse post-surgery. The majority reported the presence of one or multiple sexual challenges. There were no significant differences in postoperative sexual function or sexual difficulties between groups treated with early versus late puberty suppression.

CLINICAL IMPLICATIONS

With these findings, more adequate and tailored information on the expected effects of early endocrine gender-affirming treatment (including puberty suppression) can be given by healthcare professionals.

STRENGTHS AND LIMITATIONS

This is the first study that has assessed sexual functioning of transgender individuals treated with puberty suppression, and has differentiated between the pubertal stage at treatment initiation. Limitations were the small cohort size and retrospective study design. This study focuses on sexual functioning, however, it is important to realize sexual wellbeing is multifactorial and encompasses more than genital functioning or the ability to have certain sexual experiences.

CONCLUSION

This study found that post-vaginoplasty transfeminine individuals after both early and late suppression of puberty have the ability to experience sexual desire and arousal, and to achieve orgasms. Outcomes are comparable to previous findings in those who started treatment in adulthood.

Progress in the Stereoselective Synthesis Methods of Pyrrolidine-Containing Drugs and Their Precursors

The presented review systematizes and summarizes the data on the synthesis of pyrrolidine derivatives, which are precursors for obtaining drugs. Based on the analysis of published data, the most promising directions in the synthesis of biologically active compounds containing a pyrrolidine ring are identified. Stereoselective synthesis methods are classified based on the source of the pyrrolidine ring. The first group includes methods that use a pyrrolidine ring as the starting compound. The second group combines stereoselective methods of cyclization of acyclic starting compounds, which lead to optically pure pyrrolidine derivatives.

Current practices in oncofertility counseling: updated evidence on fertility preservation and post-treatment pregnancies in young women affected by early breast cancer

INTRODUCTION

Anticancer treatments have significantly contributed to increasing cure rates of breast cancer in the last years; however, they can also lead to short- and long-term side effects, including gonadotoxicity, and compromised fertility in young women. Oncofertility is a crucial issue for young patients who have not yet completed their family planning at the time of cancer diagnosis.

AREAS COVERED

This review aims to cover all the latest available evidence in the field of oncofertility, including the gonadotoxicity of currently adopted anticancer therapies in the curative breast cancer setting, the available strategies for fertility preservation and the feasibility of achieving a pregnancy following anticancer treatment completion.

EXPERT OPINION

Over the past years, a significant progress has been made in oncofertility care for young women with breast cancer. In the context of the currently available evidence, every young woman with newly diagnosed breast cancer should receive a proper and complete oncofertility counseling before starting any anticancer treatment to increase her chances of future pregnancies.

Puberty suppression in adolescents with gender dysphoria: an emerging issue with multiple implications

Controversy exists over puberty suppression (PS) in adolescents with gender dysphoria (GD). PS is preferentially achieved with GnRH analogues. By preventing the development of secondary sex characteristics, PS may improve psychological functioning, well-being, quality of life, emotional and behavioral (especially internalizing) problems and depressive symptoms, thus decreasing suicidality. PS can also extend the diagnostic period and give transgender adolescents time to explore their gender identity. GnRHa may also decrease the need for feminization/masculinization surgery. However, 2-year treatment with GnRHa may result in bone mass accrual retardation (decrease in BMD/BMAD z-scores), growth velocity deceleration (decrease in height SDS), increase in fat mass, temporary pause in oocyte/sperm maturation. The most common side effects of GnRHa are hot flashes, mood fluctuations, fatigue and headache. They are usually mild and rarely lead to GnRHa discontinuation. Based on current scientific evidence, PS could be recommended to adolescents who meet the diagnostic criteria of gender incongruence (by DSM-5 and/or ICD-11) and have long-lasting intense GD, which aggravates with puberty onset. Before initiating PS, possible mental issues should be addressed and informed consent (by the adolescent/caregiver) should be given, after counseling on probable reproductive effects of GnRHa. GnRHa can only be started after the adolescent has entered Tanner stage 2. Nevertheless, published studies are inadequate in number, small in size, uncontrolled and relatively short-term, so that it is difficult to draw safe conclusions on efficacy and safety of GnRHa. Large long-term randomized controlled trials are needed to expand knowledge on this controversial issue and elucidate the benefit and risks of PS.

Puberty Blocker, Leuprolide, Reduces Sex Differences in Rough-and-Tumble Play and Anxiety-like Behavior in Juvenile Rats

We examined the effect of the puberty blocker, leuprolide acetate, on sex differences in juvenile rough-and-tumble play behavior and anxiety-like behavior in adolescent male and female rats. We also evaluated leuprolide treatment on gonadal and pituitary hormone levels and activity-regulated cytoskeleton-protein messenger RNA levels within the adolescent amygdala, a region important both for rough-and-tumble play and anxiety-like behavior. Our findings suggest that leuprolide treatment lowered anxiety-like behavior during adolescent development, suggesting that the maturation of gonadotropin-releasing hormone systems may be linked to increased anxiety. These data provide a potential new model to understand the emergence of increased anxiety triggered around puberty. Leuprolide also reduced masculinized levels of rough-and-tumble play behavior, lowered follicle-stimulating hormone, and produced a consistent pattern of reducing or halting sex differences of hormone levels, including testosterone, growth hormone, thyrotropin, and corticosterone levels. Therefore, leuprolide treatment not only pauses sexual development of peripheral tissues, but also reduces sex differences in hormones, brain, and behavior, allowing for better harmonization of these systems following gender-affirming hormone treatment. These data contribute to the intended use of puberty blockers in stopping sex differences from developing further with the potential benefit of lowering anxiety-like behavior.

Puberty Assessment and Consideration of Gonadotropin-Releasing Hormone Agonists in Transgender and Gender-Diverse Youth

Transgender and gender-diverse (TGD) youth may pursue gender-affirming medical therapy in the form of gonadotropin-releasing hormone analogues (GnRHa), or "puberty blockers," if pubertal changes result in the development or worsening of gender dysphoria. GnRHa monotherapy can allow TGD youth to explore gender without the distress of unwanted secondary sexual characteristics. However, given the potential effects of GnRHa on growth, skeletal development, neurodevelopment, fertility, and future surgical outcomes, it is critical to accurately assess pubertal status to facilitate fully informed conversations with TGD youth and families about risks, benefits, and unknown consequences of GnRHa monotherapy. The focus of this discussion will be on the approach to puberty assessment in TGD youth as well as the different effects of GnRHa monotherapy that may be important to TGD youth and their families. [Pediatr Ann. 2023;52(12):e462-e466.].

Breast Cancer and Fertility Preservation in Young Female Patients: A Systematic Review of the Literature

INTRODUCTION

Breast cancer affects almost 1.5 million women worldwide below the age of 45 years each year. Many of these women will be advised to undergo adjuvant chemotherapy to minimize the risk of death or recurrence of the tumor. For these patients, chemotherapy is a known cause of infertility, as it can damage primordial follicles, which can lead to early menopause or premature ovarian insufficiency. This systematic review aims to synthesize the current evidence of the most suitable treatments for fertility preservation.

METHODOLOGY

This review was performed following the PRISMA guidelines. The authors conducted an extensive search from the last 15 years. Relevant studies were pursued in PubMed, Embase, and the Cochrane Library up until 31 July 2023. A total of seven eligible studies were identified.

RESULTS

From the reviewed literature, ovarian suppression with gonadotropin-releasing hormone agonists showed promising results in preserving fertility for breast cancer patients undergoing chemotherapy. Additionally, oocyte and embryo cryopreservation demonstrated successful outcomes, with embryo cryopreservation being the most effective option. Notably, the slow-freezing and vitrification methods were both effective in preserving embryos, with vitrification showing superior results in clinical-assisted reproductive technologies. Ovarian tissue cryopreservation emerged as a viable option for prepubertal girls and those unable to undergo conventional ovarian stimulation. The potential of in vitro maturation (IVM) as an alternative method presents a promising avenue for future fertility preservation research.

DISCUSSION

The most suitable treatments for fertility preservation in young patients is the temporary suppression with luteinizing hormone-releasing analogs, while the patient undergoes chemotherapy and cryopreservation. For cryopreservation, the physicians might deem it necessary to either cryopreserve ovarian tissue taken from the patient before any treatment or cryopreserve embryos/oocytes. Cryopreservation of oocytes and/or embryos is the most effective solution for fertility preservation in women of reproductive age, who have a sufficient ovarian reserve and are diagnosed with breast cancer, regardless of the histological type of the tumor. Because approximately 50% of young breast cancer patients are interested in becoming pregnant right after completion of therapy, the evolution and development of fertility preservation techniques promise to be very exciting.

AR and PI3K/AKT in Prostate Cancer: A Tale of Two Interconnected Pathways

Prostate cancer (PCa) is the most common cancer in men. The androgen receptor (AR) has a pivotal role in the pathogenesis and progression of PCa. Many therapies targeting AR signaling have been developed over the years. AR signaling inhibitors (ARSIs), including androgen synthesis inhibitors and AR antagonists, have proven to be effective in castration-sensitive PCa (CSPC) and improve survival, but men with castration-resistant PCa (CRPC) continue to have a poor prognosis. Despite a good initial response, drug resistance develops in almost all patients with metastatic CRPC, and ARSIs are no longer effective. Several mechanisms confer resistance to ARSI and include AR mutations but also hyperactivation of other pathways, such as PI3K/AKT/mTOR. This pathway controls key cellular processes, including proliferation and tumor progression, and it is the most frequently deregulated pathway in human cancers. A significant interaction between AR and the PI3K/AKT/mTOR signaling pathway has been shown in PCa. This review centers on the current scene of different AR and PI3K signaling pathway inhibitors, either as monotherapy or in combination treatments in PCa, and the treatment outcomes involved in both preclinical and clinical trials. A PubMed-based literature search was conducted up to November 2022. The most relevant and recent articles were selected to provide essential information and current evidence on the crosstalk between AR and the PI3K signaling pathways. The ClinicalTrials.gov registry was used to report information about clinical studies and their results using the Advanced research tool, filtering for disease and target.

The role of GnRH metabolite, GnRH-(1-5), in endometrial cancer

From the time of its discovery and isolation in the mammalian hypothalamus, the decapeptide, gonadotropin-releasing hormone (GnRH), has also been found to be expressed in non-hypothalamic tissues and can elicit a diverse array of functions both in the brain and periphery. In cancer, past studies have targeted the gonadotropin-releasing hormone receptors (GnRHR) as a way to treat reproductive cancers due to its anti-tumorigenic effects. On the contrary, its metabolite, GnRH-(1-5), behaves divergently from its parental peptide through putative orphan G-protein coupled receptor (oGPCR), GPR101. In this review, we will focus on the potential roles of GnRH-(1-5) in the periphery with an emphasis on its effects on endometrial cancer progression.

Safety, pharmacokinetics, and pharmacodynamics of SHR7280, an oral gonadotropin-releasing hormone antagonist in healthy premenopausal women

Background: Treatment with gonadotropin-releasing hormone (GnRH) antagonists is a powerful strategy to suppress gonadotropin activity in women with sex hormone-dependent disorders. Herein, we provide the safety, pharmacokinetics (PK), and pharmacodynamics (PD) profiles of SHR7280, an oral non-peptide GnRH antagonist in healthy premenopausal women. Methods: In this randomized, double-blinded, placebo-controlled, dose-ascending, phase 1 trial, healthy premenopausal women were randomized to receive SHR7280 or placebo orally. Four doses of SHR7280 (200, 300, 400, and 500 mg BID) were planned. Safety, PK, and PD parameters were evaluated. Results: SHR7280 presented tolerable toxicity and most adverse events were mild in severity. SHR7280 showed rapid onset of action (median T_max ranged from 1.0 to 1.2 h for each dose), and plasma exposure was dose-dependent. PD results showed that SHR7280 300 mg BID and above suppressed estrogen concentration within the estradiol (E₂) treatment window for endometriosis (20-50 pg/ml), inhibited the emergence of the peak of luteinizing hormone (LH) and the concentration of follicle stimulating hormone (FSH), and maintained the concentration of progesterone (P) in an anovulatory state (2 nmol/L). Conclusion: SHR7280 showed favorable safety, PK, and PD profiles in the dose range of 200-500 mg BID in healthy premenopausal women. This study supports the continued clinical development of SHR7280 as a GnRH antagonist for sex hormone-dependent disorders in women. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04554043, Identifier NCT04554043.

Small-molecule inhibitors, immune checkpoint inhibitors, and more: FDA-approved novel therapeutic drugs for solid tumors from 1991 to 2021

The United States Food and Drug Administration (US FDA) has always been a forerunner in drug evaluation and supervision. Over the past 31 years, 1050 drugs (excluding vaccines, cell-based therapies, and gene therapy products) have been approved as new molecular entities (NMEs) or biologics license applications (BLAs). A total of 228 of these 1050 drugs were identified as cancer therapeutics or cancer-related drugs, and 120 of them were classified as therapeutic drugs for solid tumors according to their initial indications. These drugs have evolved from small molecules with broad-spectrum antitumor properties in the early stage to monoclonal antibodies (mAbs) and antibody‒drug conjugates (ADCs) with a more precise targeting effect during the most recent decade. These drugs have extended indications for other malignancies, constituting a cancer treatment system for monotherapy or combined therapy. However, the available targets are still mainly limited to receptor tyrosine kinases (RTKs), restricting the development of antitumor drugs. In this review, these 120 drugs are summarized and classified according to the initial indications, characteristics, or functions. Additionally, RTK-targeted therapies and immune checkpoint-based immunotherapies are also discussed. Our analysis of existing challenges and potential opportunities in drug development may advance solid tumor treatment in the future.

The Hepatoprotective and Hepatotoxic Roles of Sex and Sex-Related Hormones

Most liver diseases, including acute liver injury, drug-induced liver injury, viral hepatitis, metabolic liver diseases, and end-stage liver diseases, are strongly linked with hormonal influences. Thus, delineating the clinical manifestation and underlying mechanisms of the “sexual dimorphism” is critical for providing hints for the prevention, management, and treatment of those diseases. Whether the sex hormones (androgen, estrogen, and progesterone) and sex-related hormones (gonadotrophin-releasing hormone, luteinizing hormone, follicle-stimulating hormone, and prolactin) play protective or toxic roles in the liver depends on the biological sex, disease stage, precipitating factor, and even the psychiatric status. Lifestyle factors, such as obesity, alcohol drinking, and smoking, also drastically affect the involving mechanisms of those hormones in liver diseases. Hormones deliver their hepatic regulatory signals primarily via classical and non-classical receptors in different liver cell types. Exogenous sex/sex-related hormone therapy may serve as a novel strategy for metabolic liver disease, cirrhosis, and liver cancer. However, the undesired hormone-induced liver injury should be carefully studied in pre-clinical models and monitored in clinical applications. This issue is particularly important for menopause females with hormone replacement therapy (HRT) and transgender populations who want to receive gender-affirming hormone therapy (GAHT). In conclusion, basic and clinical studies are warranted to depict the detailed hepatoprotective and hepatotoxic mechanisms of sex/sex-related hormones in liver disease. Prolactin holds a promising perspective in treating metabolic and advanced liver diseases.

Synthesis, Radiolabeling, and Preclinical Evaluation of 68Ga/177Lu-Labeled Leuprolide Peptide Analog for the Detection of Breast Cancer

Objectives: The expansion of novel and potent tumor receptor binding peptides is a promising approach for the precise targeting of various cancer. Leuprolide is a 9-residue peptide analog of gonadotropin-releasing hormone and is extensively used in the treatment of sex hormone-dependent tumors, including prostate, breast, and ovarian cancer. This preclinical study was undertaken to prepare a new radiolabeled leuprolide peptide for the detection of breast carcinoma. Methods: A 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)-coupled 9-amino acid leuprolide peptide was synthesized after typical 9-fluorenylmethyl-oxycarbonyl-based solid-phase peptide synthesis and radiolabeled with both ⁶⁸Ga and ¹⁷⁷Lu radionuclides for theranostic use. The systemic pharmacokinetics was done in healthy balb/c mice. The in vitro tumor cell binding affinity was determined on MCF7, T47D, and MDA-MB-231 breast cancer cell lines. In vivo tumor targeting and micro positron-emission tomography imaging was performed on nude mice with MCF7 breast tumor xenografts. Results: The leuprolide peptide was conveniently synthesized by solid-phase synthesis strategy and its identity and purity were validated by mass spectrometry and high-performance liquid chromatography. The peptide radiolabeled efficiently (˃94%) with both diagnostic (⁶⁸Ga) and therapeutic (¹⁷⁷Lu) radionuclides and displayed nanomolar binding potency to all three tested MCF7, T47D, and MDA-MB-231 cell lines. Fast and favorable pharmacokinetics was observed for ⁶⁸Ga/¹⁷⁷Lu-leuprolide in healthy Balb/c mice. In nude mice, ⁶⁸Ga-leuprolide peptide exhibited rapid clearance from the blood circulation with low to moderate (up to 5% ID/g) uptake/retention by the major body organs. The accumulation in the estrogen receptor-positive MCF7 tumor was 2.24% ± 0.62% ID/g at 45 min p.i, with good tumor to blood and muscle uptake ratios. The radiolabeled peptide was excreted primarily through the renal pathway. Conclusion: The encouraging results of this initial study demonstrate that additional testing of this leuprolide peptide seems to be indicated because of its convincing potential to be a new agent for the management of breast carcinoma.

A radiologist’s guide to novel anticancer therapies in the era of precision medicine

Novel anticancer agents have replaced conventional chemotherapy as first line agents for many cancers, with continued new and expanding indications. Small molecule inhibitors act on cell surface or intracellular targets and prevent the downstream signaling that would otherwise permit tumor growth and spread. Anticancer antibodies can be directed against growth factors or may be immunotherapeutic agents. The latter act by inhibiting mechanisms that cancer cells use to evade the immune system. Hormonal agents act by decreasing levels of hormones that are necessary for the growth of certain cancer cells. Cancer therapy protocols often include novel anticancer agents and conventional chemotherapy used successively or in combination, in order to maximize survival and minimize morbidity. A working knowledge of anti-cancer drug classification will aid the radiologist in assessing response on imaging.

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Novel anticancer agents include small molecule inhibitors, antibodies and hormones.

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These agents are predominantly cytostatic and inhibit factors that provide a survival advantage to tumor cells.

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Modern cancer therapy employs a combination of novel anticancer agents and conventional chemotherapy.

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It is essential for radiologists to have a broad understanding of these agents and their mechanisms of action.

Eliminating Hormones With Orally Active Gonadotropin-releasing Hormone Antagonists

Gonadotropin-releasing hormone (GnRH) analogues have been used in clinical practice for nearly 3 decades. Beginning with GnRH agonists, these agents have been used to treat hormone-dependent disease and to suppress gonadotropin production in assisted reproductive technologies. With the development of GnRH antagonists and especially small-molecule antagonists, our ability to achieve gonadotropin and sex steroid suppression has become increasingly effective and convenient. In this review, we will briefly describe the development of GnRH analogues, review the evolution of orally active small-molecule GnRH antagonists and provide an overview of the expanding role of small-molecule GnRH antagonists in clinical practice.

Relugolix, an oral gonadotropin-releasing hormone antagonist for the treatment of prostate cancer

Androgen deprivation therapy using gonadotropin-releasing hormone (GnRH) analogues is standard treatment for intermediate and advanced prostate cancer. GnRH agonist therapy results in an initial testosterone flare, and increased metabolic and cardiovascular risks. The GnRH antagonist relugolix is able to reduce serum testosterone levels in men with prostate cancer without inducing testosterone flare. In the HERO Phase III trial, relugolix was superior to leuprolide acetate at rapidly reducing testosterone and continuously suppressing testosterone, with faster post-treatment recovery of testosterone levels. Relugolix was associated with a 54% lower incidence of major adverse cardiovascular events than leuprolide acetate. As the first oral GnRH antagonist approved for the treatment of advanced prostate cancer, relugolix offers a new treatment option.

First pre-filled pen device with highly purified human menopausal gonadotropin (HP-hMG, Menopur) in liquid is shown to be bioequivalent to powder for reconstitution

OBJECTIVE

To determine whether serum human follicle-stimulating hormone (FSH) levels after single subcutaneous dosing of highly purified human menopausal gonadotropins (HP-hMG) in a liquid formulation and a powder formulation are bioequivalent.

MATERIALS AND METHODS

This was a randomized, two-way, crossover, single-dose, bioequivalence trial comparing Menopur liquid injected by pre-filled pen, with Menopur powder injected by conventional syringe and needle. The primary endpoints were AUC_t and C_max of baseline-adjusted FSH. Pituitary-suppressed, healthy women were administered single subcutaneous injections of 450 IU Menopur liquid (600 IU/0.96 mL) and 450 IU Menopur powder (by 2 subcutaneous injections of 225 IU in 1 mL) in a randomized order. The pharmacokinetic parameters of FSH and human chorionic gonadotropin (hCG) were assessed by non-compartmental methods with adjustment for endogenous pre-dose levels.

RESULTS

In total, 76 women were randomized, and 56 completed the trial. The mean FSH and hCG serum concentration-time profiles were comparable between the two HP-hMG formulations. The geometric mean ratios and 90% confidence intervals of FSH for HP-hMG liquid versus HP-hMG powder were 1.12 (1.0562 - 1.1889) for AUC_t and 1.17 (1.0946 - 1.2490) for C_max, showing that the two formulations were bioequivalent. The incidence and severity of adverse events were similar between the two preparations, and both preparations were well tolerated.

CONCLUSION

The 90% CIs for the geometric mean ratios of serum FSH AUC_t and C_max were both within 0.8000 - 1.2500, thus the two formulations are bioequivalent.

Favorable Effects of GLP-1 Receptor Agonist against Pancreatic β-Cell Glucose Toxicity and the Development of Arteriosclerosis: "The Earlier, the Better" in Therapy with Incretin-Based Medicine

Fundamental pancreatic β-cell function is to produce and secrete insulin in response to blood glucose levels. However, when β-cells are chronically exposed to hyperglycemia in type 2 diabetes mellitus (T2DM), insulin biosynthesis and secretion are decreased together with reduced expression of insulin transcription factors. Glucagon-like peptide-1 (GLP-1) plays a crucial role in pancreatic β-cells; GLP-1 binds to the GLP-1 receptor (GLP-1R) in the β-cell membrane and thereby enhances insulin secretion, suppresses apoptotic cell death and increase proliferation of β-cells. However, GLP-1R expression in β-cells is reduced under diabetic conditions and thus the GLP-1R activator (GLP-1RA) shows more favorable effects on β-cells at an early stage of T2DM compared to an advanced stage. On the other hand, it has been drawing much attention to the idea that GLP-1 signaling is important in arterial cells; GLP-1 increases nitric oxide, which leads to facilitation of vascular relaxation and suppression of arteriosclerosis. However, GLP-1R expression in arterial cells is also reduced under diabetic conditions and thus GLP-1RA shows more protective effects on arteriosclerosis at an early stage of T2DM. Furthermore, it has been reported recently that administration of GLP-1RA leads to the reduction of cardiovascular events in various large-scale clinical trials. Therefore, we think that it would be better to start GLP-1RA at an early stage of T2DM for the prevention of arteriosclerosis and protection of β-cells against glucose toxicity in routine medical care.

Cardiovascular Toxicity of Androgen Deprivation Therapy

PURPOSE OF REVIEW

Androgen deprivation therapy (ADT) is the standard of care for the treatment of advanced prostate cancer (PC). ADT, particularly with GnRH agonists, leads to increased risk of cardiovascular disease, including myocardial infarction, hypertension, and stroke. This review discusses the options of ADT, the mechanism of ADT-associated cardiovascular side effects, and potential benefit by using GnRH antagonists.

RECENT FINDINGS

GnRH antagonists have relatively less cardiovascular adverse effects compared to GnRH agonists. We highlight on a recently published phase III clinical trial on the oral GnRH antagonist, relugolix, and its comparative benefit to traditional GnRH agonist regarding development of cardiovascular disease. Recent data reinforces that GnRH antagonists have a more favorable cardiovascular outcomes compared to GnRH agonists yet maintain a similar efficacy profile. From the data we reviewed, GnRH antagonists may be the preferred method of ADT for PC, but further data with primary cardiovascular outcomes are warranted.

Hormonal Therapy for Prostate Cancer

Huggins and Hodges demonstrated the therapeutic effect of gonadal testosterone deprivation in the 1940s and therefore firmly established the concept that prostate cancer is a highly androgen-dependent disease. Since that time, hormonal therapy has undergone iterative advancement, from the types of gonadal testosterone deprivation to modalities that block the generation of adrenal and other extragonadal androgens, to those that directly bind and inhibit the androgen receptor (AR). The clinical states of prostate cancer are the product of a superimposition of these therapies with nonmetastatic advanced prostate cancer, as well as frankly metastatic disease. Today's standard of care for advanced prostate cancer includes gonadotropin-releasing hormone agonists (e.g., leuprolide), second-generation nonsteroidal AR antagonists (enzalutamide, apalutamide, and darolutamide) and the androgen biosynthesis inhibitor abiraterone. The purpose of this review is to provide an assessment of hormonal therapies for the various clinical states of prostate cancer. The advancement of today's standard of care will require an accounting of an individual's androgen physiology that also has recently recognized germline determinants of peripheral androgen metabolism, which include HSD3B1 inheritance.

Growth, growth potential, and influences on adult height in the transgender and gender-diverse population

The sexually dimorphic trait of height is one aspect of the experience of transgender and gender‐diverse (TGD) individuals that may influence their gender dysphoria and satisfaction with their transition. In this article, we have reviewed the current knowledge of the factors that contribute to one's final adult height and how it might be affected in TGD youth who have not experienced their gonadal puberty in the setting of receiving gonadotropin‐releasing hormone analog (GnRHa) and gender‐affirming hormonal treatment. Additional research is needed to characterize the influence of growth and final adult height on the lived experience of TGD youth and adults and how to best assess their growth, predict their final adult height, and how medical transition can be potentially modified to help them meet their goals.

No significant long-term complications from inadvertent exposure to gonadotropin-releasing hormone agonist during early pregnancy in mothers and offspring: a retrospective analysis

BACKGROUND

Administration of gonadotropin-releasing hormone agonist (GnRH-a) in the luteal phase is commonly used for pituitary suppression during in vitro fertilisation (IVF). There is an ineluctable risk of inadvertent exposure of spontaneous pregnancy to GnRH-a. However, little is known about the pregnancy complications and repregnancy outcomes of the affected women and the neurodevelopmental outcomes of the GnRH-a-exposed children.

METHODS

Retrospective analysis was used to determine obstetric and repregnancy outcomes after natural conception in 114 women who naturally conceived while receiving GnRH-a during their early pregnancy over the past 17 years. The GnRH-a-exposed children were evaluated to determine their neonatal characteristics and long-term neurodevelopmental outcomes. The outcomes were compared to those of relevant age-matched control groups.

RESULTS

Sixty-five women had 66 live births. The neonatal health outcomes and the incidence of maternal complications were similar in the GnRH-a-exposed and control groups. Thirty-one GnRH-a-exposed children, aged 2-8 years, were available for investigation of neurodevelopment. Except for one case of autism spectrum disorder, the full-scale intelligence quotient score was within the normal range and similar to that of the control group. Most mothers with successful pregnancies and about one-third of the women who had spontaneous abortions were subsequently able to conceive naturally again. IVF is recommended for repregnancy in women who have experienced ectopic pregnancies.

CONCLUSIONS

Accidental exposure to GnRH-a in early pregnancy might be safe. Reproductive treatment suggestions for repregnancy should be made with consideration of the outcomes of the previously GnRH-a-exposed spontaneous pregnancy.

Is gonadotropin-releasing hormone agonist usage really leading to thyroid dysfunction?

Objectives

Gonadotropin-releasing hormone agonist (GnRHa) could influence the levels of sex hormones and thyroid hormones. The aim of this study was to investigate the effect of GnRHa on thyroid function.

Materials and methods

The data of the patients were collected from the registrations of July 2014–October 2014. A total of 41 women who underwent one-time IVF cyclus were evaluated in this cross-sectional study. The patients were categorized into two groups according to the serum T₃, T₄, and TSH levels before and 2 weeks’ after the administration of GnRHa.

Results

Mean basal TSH and mean TSH levels on hCG day were 1.98 ± 0.77 and 1.75 ± 0.70, respectively. The difference between the two groups was statistically significant (p < 0.05). GnRHa did not lead to statistically significant difference on serum-free T₃ and T₄ levels.

Conclusions

In conclusion, our results demonstrate that GnRHa led to a decrease on serum TSH level. Serum-free T₃ and T₄ levels were remained unchanged and this might be due to early measurement of the hormone levels (just 2 weeks later from GnRHa administration).

Microencapsulation of luteinizing hormone-releasing hormone agonist in poly (lactic-co-glycolic acid) microspheres by spray-drying

A spray drying technique was developed to prepare injectable and biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres encapsulating a model luteinizing hormone-releasing hormone agonist (LHRHa)-based peptide, leuprolide. Various spray drying parameters were evaluated to prepare 1-month controlled release formulations with a similar composition to the commercial Lupron Depot® (LD). A single water-in-oil emulsion of aqueous leuprolide/gelatin solution in PLGA 75/25 acid capped (13 kDa Mw) dissolved in methylene chloride (DCM) was spray-dried before washing the microspheres in cold ddH2O and freeze-drying. The spray-drying microencapsulation was characterized by: particle size/distribution (span), morphology, drug/gelatin loading, encapsulation efficiency, and residual DCM and water content. Long-term release was tested over 9 weeks in PBS + 0.02% Tween 80 + 0.02% sodium azide pH 7.4 (PBST) at 37 °C. Several physical-chemical parameters were monitored simultaneously for selected formulations, including: water uptake, mass loss, dry and hydrated glass transition temperature, to help understand the related long-term release profiles and explore the underlying controlled-release mechanisms. Compared with the commercial LD microspheres, some of the in-house spray-dried microspheres presented highly similar or even improved long-term release profiles, providing viable long-acting release (LAR) alternatives to the LD. The in vitro release mechanism of the peptide was shown to be controlled either by kinetics of polymer mass loss or by a second process, hypothesized to involve peptide desorption from the polymer. These data indicate spray drying can be optimized to prepare commercially relevant PLGA microsphere formulations for delivery of peptides, including the LHRHa, leuprolide.

A Case of Paraphilia with Osteoporosis and Administered with Depot Leuprorelin

Paraphilia is a complex psychological and psychiatric disorder that has been difficult to treat. Leuprorelin has been used as one of the therapeutic methods for paraphilia. Leuprorelin administration could change insulin resistance and accelerate bone loss. The case study in this work was a 59-year-old man who visited a hospital with the chief complaints of frotteuristic behaviors in public places, a continuous increase in sexual desire, and sexual molestation behavior that started in 2007. We injected leuprorelin (3.6 mg) intramuscularly every month for this patient with paraphilia and comorbidities of osteoporosis and hyperthyroidism. The clinical global impression (CGI), Sex Addiction Screening Test (SAST), Wilson Sex Fantasy Questionnaire (WSFQ), physical examination, and laboratory tests were performed. After 12 months of leuprorelin injection for paraphilia, we found a significant improvement in abnormal sexual behavior/desire without aggravation of osteoporosis/hyperthyroidism. Gonadotrophin-Releasing Hormone (GnRH) analogs could be used as alternative or supplementary treatment methods for paraphilia with osteoporosis/hyperthyroidism.

Dynamic Changes of RFRP3/GPR147 in the Precocious Puberty Model Female Rats

BACKGROUND

Pubertal development is a complex physiological process regulated by the neuroendocrine system and hypothalamic-pituitary-gonadal axis. Sexual precocity is a common childhood endocrine disease.The pathogenesis of sexual precocity has not been fully elucidated. RFRP3/GPRl47 signal pathway is able to inhibit the reproductive capability in avians and mammals, probably by acting on the GnRH neuron and pituitary to regulate gonadotrophin synthesis and release. However, little is known about the role of RFRP3 in puberty development and sexual precocity.

OBJECTIVE

To observe the dynamic changes of RFamide related peptide 3/G proteincoupled receptor 147 (RFRP3/GPR147) in hypothalamic during puberty development and explore their role in precocious puberty based on a female rat model.

METHODS

The Sprague-Dawley female rats were randomly divided into three groups, normal, vehicle, and precocious puberty model. At 5 days old, the rat model with precocious puberty was prepared by subcutaneously injecting a mixture of danazoldissolved ethanol and glycol. At different day-age (15, 25, 30, 35, and 40 days), the levels of estradiol(E2), follicle-stimulating hormone(FSH), and luteinizing hormone (LH) in the peripheral blood were detected by the enzyme-linked immunosorbent assay, the messenger ribonucleic acid (mRNA) expressions of RFRP3, gonadotropin releasing hormone and GPR147 were examined by real-time polymerase chain reaction(R-T PCR). RFRP3 positive cells were observed using Immunofluorescence confocal microscopy.

RESULTS

At 25 and 30 days, the levels of sex hormones and the uterus coefficients were significantly higher in the precocious puberty model group than those in the normal and vehicle groups. The ovarian morphological development in the precocious puberty model rats was significantly earlier than those in the normal and vehicle groups. The mRNA expressions of RFRP3/GPR147 and GnRH in the precocious puberty model group gradually increased and peaked at 25 days. The different day-age and the interaction have significant statistical significance on the expression of RFRP3 mRNA, while the levels of RFRP3 mRNA in the model group and vehicle groups have no significant statistical significance. There was statistical significance between the model group and vehicle groups in different day-age on the expression of GPR147 mRNA.The expression of hypothalamic RFRP3/GPR147 mRNA and RFRP3 positive cells gradually decreased with puberty onset. At 35 days, the levels of RFRP3 mRNA and GPR147 mRNA were significantly lower in the precocious puberty model group than those in the vehicle groups. Meanwhile, the levels of LH in the precocious puberty model rats reached its peak at this age. In the vehicle group, the levels of RFRP3 mRNA and serum LH were gradually increased and LH nearly peaked at 35 day-age. Subsequently, it gradually decreased and reached the lowest level at 35 day-age. The expression of RFRP3 mRNA and LH were positively correlated.

CONCLUSION

The findings suggested that RFRP3/GPR147 signaling pathway may be involved in the pathogenesis of sexual precocity by regulating puberty development and sexual maturity in rats.

Evaluation of infertility efficacy of the E. coli expressed STF2-GnRH vaccine in male cats

Gonadotropin-releasing hormone (GnRH) is secreted from the hypothalamus and anti-GnRH antibodies are not formed under normal conditions. However, administration an excess of recombinant GnRH protein results in the formation of anti-GnRH. We evaluated the efficacy of the recombinant Salmonella typhimurium flagellin fljB (STF2)-GnRH vaccine in inducing infertility in 17 intact male cats. The first vaccination and a boosting vaccine was injected for examination. Serum was obtained from blood collected at monthly intervals and anti-GnRH antibodies and testosterone concentrations were determined. Six months after the vaccination, testicular samples are obtained and used for histological examination. Compared with sham control group, the injection groups showed an increase in anti-GnRH antibody titers and testosterone concentrations tended to be reduced in the injection groups and increased in the control group. Histological evaluations and Johnsen's testicular biopsy scores revealed testicular hypoplasia in the 2 injection groups. Consequently, normal sexual maturation with sperm production was observed in the control group. In contrast, the cats that received the GnRH vaccine showed weak (2 of 7 cats) or moderate (4 out of 7 cats) dose-dependent infertility effects. On the basis of the results, the STF2-GnRH vaccine was identified to be effective in inducing infertility in male cats. The results of this study thus indicate the possibility of immunological castration targeting feral cats.

Transition memories: experiences of trans adult women with hormone therapy and their beliefs on the usage of hormone blockers to suppress puberty

PURPOSE

In recent years, an increasing number of specialized gender clinics have been prescribing gonadotropin-releasing hormone (GnRH) analogs to adolescents diagnosed with gender dysphoria (GD) to suppress puberty. This paper presents qualitative research on the hormone therapy (HT) experiences of older trans-people and their views on puberty suppression. The main aim of this research was to explore the psychological aspects of hormonal treatments for gender non-conforming adults, including the controversial use of puberty suppression treatments.

METHODS

Using a semi-structured interview format, ten adult trans-women were interviewed (mean age: 37.4) to explore their personal histories regarding GD onset and development, their HT experiences, and their views on the use of GnRH analogs to suppress puberty in trans-children and adolescents.

RESULTS

the interview transcripts were analyzed using the consensual qualitative research method from which several themes emerged: the onset of GD, childhood experiences, experiences with puberty and HT, views on the puberty suspension procedure, and the effects of this suspension on gender identity and sexuality.

CONCLUSIONS

The interviews showed that overall, the participants valued the new treatment protocol due to the opportunity to prevent the severe body dysphoria and social phobia trans-people experience with puberty. It seems that the risk of social isolation and psychological suffering is increased by the general lack of acceptance and stigma toward trans-identities in the Italian society. However, during gender transitions, they highlight the need to focus more on internal and psychological aspects, rather than over-emphasize physical appearance. This study gives a voice to an under-represented group regarding the use of GnRH analogs to suppress puberty in trans-individuals, and collected firsthand insights on this controversial treatment and its recommendations in professional international guidelines.

Non-surgical artificial insemination using a GnRH analogue for ovulation induction during natural oestrus in African lions (Panthera leo)

Despite postulated potential for wildlife conservation, success of assisted reproduction techniques (ART) in ex-situ feline breeding remains <25%. The aim of this project was to develop a simplified, non-surgical artificial insemination (AI) protocol for African lions (Panthera leo), using an exogenous GnRH analogue to induce ovulation in females presenting natural oestrus, and minimizing manipulation of the animals. Four protocols were tested in five trained lionesses (3.5-8 years), for a total of 14 inseminations (2-4 per lioness). These protocols differed in the time lapse between GnRH injection and insemination, on days 4, 5, or 6 from onset of natural oestrus, determined by daily behavioural observation and vaginal cytology. Semen was collected from 8 different males by urethral catheterization and electro-ejaculation, during full anaesthesia. Females were immediately immobilized for AI after semen collection. After transrectal ultrasound examination of the reproductive tract, insemination was performed either intravaginal or transcervical using a commercial dog urinary catheter (2.0 × 500 mm, Buster^®, Krusse, South Africa) with a metal stylet. A single intramuscular dose of exogenous GnRH (20 μg burserelin-acetate, Receptal^®, MSD, Intervet, South Africa) administered 30 or 48 h before AI or during the AI procedure induced ovulation successfully, as all females entered either a non-pregnant luteal phase of 59.6 ± 0.95 days (n = 10) or a pregnant luteal phase of 111.7 ± 0.33 days (n = 3). However, the timespan between GnRH injection and end of behavioural and/or cytological oestrus differed widely (range: 0-120 h). The final pregnancy success rate was 33.3%.

Drug-Drug Interactions in Prostate Cancer Treatment

Polypharmacy is associated with an increased risk of drug-drug interactions (DDIs), which can cause serious and debilitating drug-induced adverse events. With a steadily aging population and associated increasing multimorbidity and polypharmacy, the potential for DDIs becomes considerably important. Prostate cancer (PCa) is the most common cancer in men and occurs mostly in elderly men in the Western world. Therefore, the aim of this review is to give an overview of DDIs in PCa therapy to better understand pharmacodynamic and pharm kinetic side effects as well as their interactions with other medications. Last, we explore potential future strategies, which might help to optimize treatment and reduce adverse events patients with polypharmacy and PCa.

Gonadotropin-releasing hormone agonists during chemotherapy for ovarian function and fertility preservation for patients with early-stage breast cancer

Breast cancer remains the most common cancer among women worldwide. Many patients, especially in our region, are affected while young and during their child-bearing years. Chemotherapy, more commonly used in this age group, may result in premature ovarian failure and thus negatively impact their fertility. Several fertility-preservation methods are currently in use in this age group. Unfertilized ova cryopreservation and in vitro fertilization plus embryo cryopreservation are widely used in clinical practice. More recently, ovarian tissue cryopreservation is gaining in popularity. Several clinical trials and meta-analyses have shown that premenopausal women who received ovarian function suppression with gonadotropin-releasing hormone agonists while on chemotherapy were less likely to experience ovarian failure and had higher rates of menses resumption compared to those who did not. Some studies have also shown higher rates of successful pregnancies among treated patients. Given the conflicting results of the reported clinical trials and even the many published meta-analyses, this approach continues to be controversial and should only be used when other established fertility preservation methods cannot be utilized. The current review seeks to provide an updated summary on this controversial topic by reviewing all recently published clinical trials and meta-analyses.

A phase 3, open-label, multicenter study of a 6-month pre-mixed depot formulation of leuprolide mesylate in advanced prostate cancer patients

Objectives

To determine the safety, efficacy and pharmacokinetic (PK) profile of a pre-mixed depot formulation of leuprolide mesylate subcutaneous injectable suspension (LMIS) 50 mg for up to 1 year of treatment for subjects with advanced prostate cancer.

Patients and methods

In this open-label, multicenter study, prostate cancer patients with indication for androgen ablation therapy received two subcutaneous injection of LMIS 50 mg 6 months apart and were followed for an additional 6 months. Two efficacy primary end points were the percentage of subjects with a serum testosterone level ≤ 50 ng/dL by Day 28 as well as the percentage of subjects with similar testosterone suppression from Day 28 to Day 336.

Results

Of the 137 enrolled subjects, 15 (10.9%) subjects did not complete the study, including 5 subjects who terminated early due to an adverse event. By Day 28, 98.5% (95% confidence interval 94.8–99.8) of the subjects achieved a castrate testosterone level. At the end of the study, 97% and 95.9% of the subjects had serum testosterone level ≤ 50 ng/dL and ≤ 20 ng/dL, respectively. LMIS 50 mg significantly reduced serum prostate-specific antigen levels after its first injection and this PSA declination effect remained until the end of the study. No statistically significant change was observed in worsening bone pain or urinary symptom assessments during the study. Hot flush (48.9%) and hypertension (14.6%) were the two most common adverse events reported.

Conclusions

LMIS 50 mg, administered at 6-month intervals, effectively suppressed serum testosterone level, and demonstrated a consistent safety profile.

Gonadotropin-releasing hormone analog therapeutics

Dysregulation at any level of the hypothalamic-pituitary-gonadal (HPG) axis results in, or aggravates, a number of hormone-dependent diseases such as delayed or precocious puberty, infertility, prostatic and ovarian cancer, benign prostatic hyperplasia, polycystic ovarian syndrome, endometriosis, uterine fibroids, lean body mass, as well as metabolism and cognitive impairment. As gonadotropin-releasing-hormone (GnRH) is an essential regulator of the HPG axis, agonist and antagonist analogs are efficacious in the treatment of these conditions. GnRH analogs also play an important role in assisted reproductive therapies. This review highlights the current and future therapeutic potential of GnRH analogs and upstream regulators of GnRH secretion.

Therapeutic Effects of Leuprorelin (Leuprolide Acetate) in Sexual Offenders with Paraphilia

BACKGROUND

This study examined the clinical effects of leuprolide acetate in sexual offenders with paraphilic disorders evaluated by means of objective psychiatric assessment.

METHODS

The subjects of this study were seven sexual offenders who were being treated by means of an injection for sexual impulse control by a court order. They had been diagnosed with paraphilia by a psychiatrist based on the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) and had been put on probation by the Ministry of Justice between January 2016 and December 2016.

RESULTS

After twelve months, we observed significant improvement in symptoms, as decrease of abnormal sexual interest and activity, sexual fantasy, Clinical Global Impression-Severity (CGI-S), and Clinical Global Impression-Impulsivity (GCI-I). There were a mild feminization of the body shape, feelings of fatigue, and mild hot flushes. No other adverse effect was reported.

CONCLUSION

These results suggested that the clinical effects of leuprolide acetate in sexual offenders might be an effective treatment and safety strategy.

'Spare' Luteinizing Hormone Receptors: Facts and Fiction

It is common opinion that maximal activation of luteinizing hormone (LH)-dependent steroidogenic signal occurs at <1% of human LH/choriogonadotropin (hCG) receptor (LHCGR) occupancy. This effect would be a consequence of an excess of receptors expressed on the surface of theca cells, resulting in a pool of LHCGRs remaining unbound (spare). This concept was borrowed from historical pharmacological studies, when discrepancies between ligand-receptor binding and dose-response curves of cAMP were evaluated by treating mouse or rat Leydig cells with hCG in vitro. Recent findings demonstrated the specificity of LH- and hCG-dependent effects, receptor heterodimerization, and differing behaviors of rodent versus human gonadotropin-responsive cells, which may help to revise the 'spare' LHCGRs concept applied to human ovarian physiology and assisted reproduction.

Gonadotropin-Releasing Hormone Receptor Antagonist Mono- and Combination Therapy With Estradiol/Norethindrone Acetate Add-Back: Pharmacodynamics and Safety of OBE2109

Context

OBE2109 is a potent, oral gonadotropin-releasing hormone receptor antagonist being developed for the treatment of sex-hormone-dependent diseases in women.

Objective

We assessed the pharmacodynamics and safety of OBE2109 alone and combined with estradiol (E2)/norethindrone acetate (NETA) add-back therapy on E2 levels and vaginal bleeding.

Design, Setting, and Participants

This was a single-center, open-label, randomized, parallel-group study in 76 healthy premenopausal women.

Interventions

Women were randomly assigned to take the following doses (in milligrams) once daily for 6 weeks: OBE2109, 100 or 200; or OBE2109/E2/NETA, 100/0.5/0.1, or 100/1.0/0.5, or 200/1.0/0.5.

Main Outcome Measures

E2 concentrations, bleeding pattern, exploratory bone metabolism biomarkers, and adverse events.

Results

OBE2109 100 mg and 200 mg alone reduced E2 levels to reach median levels of 19.5 and 3.2 pg/mL, respectively, at week 4. Median E2 levels after combined OBE2109/add-back therapy ranged between 25 and 40 pg/mL. OBE2109 100 mg or 200 mg alone induced amenorrhea. By day 15, >85% of women had no vaginal bleeding during the last 4 weeks of treatment. Add-back therapy partially impaired bleeding control: The highest amenorrhea rate (53%) was observed with OBE2109 100 mg/1.0 mg/0.5 mg. The addition of E2/NETA, particularly at 1 mg/0.5 mg, mitigated the increase of two bone markers induced by OBE2109 200 mg.

Conclusion

OBE2109 promptly lowered E2 levels. Add-back therapy may be required to prevent adverse effects on bone in women treated with the 200-mg dose (at 100 mg in some women). These results provide a basis for OBE2109 regimen selection to treat sex-hormone-dependent diseases.

Degarelix treatment is compatible with diabetes and antithrombotic therapy in patients with prostate cancer

Introduction

Therapeutically induced androgen deficiency (AD) is a standard treatment for patients with prostate cancer, but it is often associated with various adverse effects (AEs) that may lead to discontinuation. Some AEs may depend on the patient's health condition, while others may be due to complications of the drug delivery method. Degarelix is a gonadotropin-releasing hormone (GnRH) antagonist widely used for the treatment of androgen-dependent prostate cancer. This study aimed to ascertain the following: 1) the compatibility of degarelix treatment with diabetes and 2) any specific causal associations of degarelix injections with increased blood clotting and antithrombotic therapy requirements.

Patients and methods

The medical records of 162 patients with prostate cancer who had undergone degarelix treatment were retrospectively examined. The association of a medical history of diabetes and anticoagulant co-treatment with degarelix treatment discontinuation was analyzed statistically.

Results

Rapid and significant decreases in prostate-specific antigen (PSA) levels during the course of degarelix treatment were detected for patients with prostate cancer regardless of clinical state. During the 27 months of treatment, 68 subjects (48%) ceased degarelix treatment, owing to several reasons, mainly financial issues. Among these subjects, 19 had diabetes, while 35 were treated with antithrombotics. Extensive statistical analysis indicated that there were no causal associations between degarelix treatment discontinuation and preexisting diabetes or antithrombotic therapy.

Conclusion

Our study suggests that preexisting diabetes and antithrombotic therapy were not significant factors for the discontinuation of degarelix treatment in patients with prostate cancer.

Recent Development of Non-Peptide GnRH Antagonists

The decapeptide gonadotropin-releasing hormone, also referred to as luteinizing hormone-releasing hormone with the sequence (pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH₂) plays an important role in regulating the reproductive system. It stimulates differential release of the gonadotropins FSH and LH from pituitary tissue. To date, treatment of hormone-dependent diseases targeting the GnRH receptor, including peptide GnRH agonist and antagonists are now available on the market. The inherited issues associate with peptide agonists and antagonists have however, led to significant interest in developing orally active, small molecule, non-peptide antagonists. In this review, we will summarize all developed small molecule GnRH antagonists along with the most recent clinical data and therapeutic applications.

Puberty suppression in transgender children and adolescents

The World Professional Association for Transgender Health's standards of care recommend suspending puberty, preferably with the use of gonadotropin-releasing hormone agonists, in certain gender non-conforming minors (aged under 18 years) who have undergone a psychiatric assessment and have reached at least Tanner stage II of puberty. This approach seeks to lessen the discordance between assigned natal sex and gender identity by temporarily halting the development of secondary sexual characteristics, essentially widening the temporal window for gender clarification. Despite promising preliminary evidence on the clinical utility of this approach, there is a dearth of research to inform evidence-based practice. In view of these challenges, we review the available empirical evidence on the cognitive, physical, and surgical implications of puberty suppression in gender-incongruent children and adolescents. We also explore the historical underpinnings and clinical impetus for suspending puberty in this population, and propose key research priorities.

How is GnRH regulated in GnRH-producing neurons? Studies using GT1-7 cells as a GnRH-producing cell model

Hypothalamic secretion of gonadotropin-releasing hormone (GnRH) has been established as a principle pathway for initiating and integrating female reproductive function. GnRH stimulates the release of two gonadotropins-luteinizing hormone and follicle-stimulating hormone-from the anterior pituitary, which eventually stimulate the synthesis of sex steroids in association with follicular growth and ovulation. This reproductive control of the hypothalamic-pituitary-gonadal (HPG) axis also mediates gonadal feedback mechanisms. Although GnRH neurons certainly play a pivotal role in the HPG axis, the detailed mechanisms of their functional network, including regulatory systems, remain unknown. After the discovery of the indispensable role of kisspeptin in the development of human reproductive functions, our understanding of the neuroendocrine regulation of the HPG axis was revolutionized, and it is now recognized that kisspeptin acts upstream of GnRH and is responsible for sex steroid feedback mechanisms. Kisspeptin can stimulate gonadotropin release from the pituitary gland by stimulating GnRH release and GnRH antagonists prevent kisspeptin-induced gonadotropin release. Furthermore, it has been shown that GnRH neurons express kisspeptin receptors. Nevertheless, the detailed mechanisms underlying the regulation of homogeneous populations of GnRH neurons are still largely unknown because of the limitations of experimental models used for investigation. The hypothalamus consists of a complex network of distinct neuronal cells, and it is difficult to isolate single-cell populations of GnRH neurons. The establishment of GnRH-expressing cell lines has allowed us to examine the events happening at the single-cell level. In this review, we describe in vitro studies using a GnRH-producing cell model, GT1-7 cells, which have been used to examine how GnRH-producing cells respond to hypothalamic factors and how they are involved in GnRH synthesis.

Discovery of LHRH and development of LHRH analogs for prostate cancer treatment

The discovery, isolation, elucidation of structure, synthesis, and initial testing of the neuropeptide hypothalamic luteinizing hormone-releasing hormone (LHRH), which regulates reproduction, is briefly described. The design, synthesis, and experimental and clinical testing of agonistic analogs of LHRH is extensively reviewed focusing on the development of new methods for the treatment of prostate cancer. Subsequent development of antagonistic analogs of LHRH is then faithfully recounted with special emphasis on therapy of prostate cancer and BPH. The concepts of targeted therapy to peptide receptors on tumors are re-examined and the development of the cytotoxic analogs of LHRH and their status is reviewed. The endeavor to develop better therapies for prostate cancer, based on LHRH analogs, guided much of our work.

Dose-Dependent Suppression of Gonadotropins and Ovarian Hormones by Elagolix in Healthy Premenopausal Women

CONTEXT

Elagolix is a nonpeptide, oral gonadotropin-releasing hormone (GnRH) antagonist being developed for sex-hormone-dependent diseases in women.

OBJECTIVE

We evaluated the pharmacokinetics and pharmacodynamics of elagolix.

DESIGN, SETTING, AND PARTICIPANTS

This study was a randomized, double-blind, placebo-controlled, multiple-ascending dose study in 45 healthy premenopausal women at a research unit.

INTERVENTIONS

Elagolix [150 mg once daily or 100, 200, 300, or 400 mg twice daily (BID)] or placebo was administered for 21 days.

MAIN OUTCOME MEASURES

Main outcome measures were elagolix pharmacokinetics, suppression of gonadotropics [follicle-stimulating hormone (FSH), luteinizing hormone (LH)] and ovarian hormones [estradiol (E2), progesterone (P)], and adverse events.

RESULTS

Elagolix was rapidly absorbed after oral dosing, reaching maximum concentrations at 1.0 to 1.5 hours, with a half-life of 4 to 6 hours. FSH, LH, and E2 were suppressed within hours of elagolix administration on day 1. Dose-dependent suppression of E2 was observed, with maximum suppression achieved with elagolix 200 mg BID. Dose-dependent suppression of FSH and LH was also observed, with maximal or near-maximal suppression achieved at 300 mg BID and 200 mg BID, respectively. At elagolix doses ≥100 mg BID, P concentrations remained at anovulatory levels throughout 21 days of dosing. The most frequently reported adverse events were headache and hot flush.

CONCLUSIONS

Elagolix administration allows for modulation of gonadotropin and ovarian hormone concentrations, from partial suppression at lower doses to nearly full suppression at higher doses. The results of this study provide a rationale for elagolix dose selection for treatment of sex hormone-dependent diseases in women.

Easy detection of hormone secretion from LβT2 cells by using Gaussia luciferase

Reproduction is regulated by gonadotropins secreted from gonadotrophs. The production and secretion of gonadotropins are mainly regulated by gonadotropin-releasing hormone (GnRH). Agonists or antagonists that influence GnRH action on gonadotrophs are important to regulate reproduction; however, these factors have not been fully characterized due to the lack of simple and easy-to-use techniques to detect gonadotropin secretion from gonadotropin-producing cells. In the present study, we found that Gaussia luciferase (Gluc), which was expressed in LβT2 cells, can be secreted like a luteinizing-hormone (LH) upon stimulation with GnRH. The Gluc secreted into the medium was easily monitored as luminescence signals. The detection range of the GnRH-induced Gluc activity was comparable to that of the enzyme-linked immunosorbent assay for LH. In addition, when the Gluc was expressed in AtT20 cells, which produce adrenocorticotropic hormone (ACTH), the Gluc activity in the medium increased in parallel with the ACTH secretion upon stimulation with corticotropin-releasing hormone. Thus, the Gluc assay in the present study can be easily used for high-throughput screening of factors that influence LH or ACTH secretion from LβT2 or AtT20 cells, respectively.

Overview of elagolix for the treatment of endometriosis

INTRODUCTION

Suppression of sex-steroid secretion is required in a variety of gynecological conditions. This can be achieved using gonadotropin releasing hormone (GnRH) agonists that bind pituitary gonadotropin receptors and antagonize the link-receptor of endogenous GnRH, inhibiting the mechanism of GnRH pulsatility. On the other hand, GnRH antagonists immediately reduce gonadal steroid levels, avoiding the initial stimulatory phase of the agonists. Potential benefits of GnRH antagonists over GnRH agonists include a rapid onset and reversibility of action. Older GnRH antagonists are synthetic peptides, obtained by modifications of certain amino acids in the native GnRH sequence. They require subcutaneous injections, implantation of long-acting depots. The peptide structure is responsible for histamine-related adverse events and the tendency to elicit hypersensitivity reactions.

AREAS COVERED

Research has worked towards the development of non-peptidic molecules exerting antagonist action on GnRH. They are available for oral administration and may have a more beneficial safety profile in comparison with peptide GnRH antagonists. This article focuses on the data of the literature about elagolix, a novel non-peptidic GnRHantagonist, in the treatment of endometriosis.

EXPERT OPINION

Elagolix demonstrated efficacy in the management of endometriosis-associated pain and had an acceptable safety and tolerability profile. However, further studies are necessary to evaluate its non-inferiority in comparison with other endometriosis's treatments.

Gonadotropin-Releasing Hormone and Its Role in the Enteric Nervous System

Gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone, and luteinizing hormone orchestrate the reproduction cycle and regulate the sex steroid secretion from the gonads. In mammals, GnRH1 is secreted as a hormone from the hypothalamus, whereas both GnRH1 and GnRH2 are present as neurotransmitters/peptides in various tissues, where the peptides exert many different effects. mRNA coding for GnRH1 and GnRH2 have been described in the human gastrointestinal tract, and GnRH has been found in both submucosal and myenteric neurons. mRNA coding for GnRH and the fully expressed peptide have been found in rat enteric neurons by some researchers but not by others. mRNA coding for GnRH receptors, but not the fully expressed receptor, has been found in one rat study. GnRH influences gastrointestinal motility and secretion. GnRH analogs are clinically used in the treatment of sex hormone-dependent diseases, i.e., endometriosis and malignancies, and as pretreatment for in vitro fertilization. Reduced numbers of enteric neurons and IgM antibodies against GnRH and progonadoliberin-2 (precursor of GnRH2) have been observed after such treatment, with the clinical picture of gastrointestinal dysmotility. Similarly, a rat model of enteric neurodegeneration has been developed after administration of the GnRH analog buserelin. Serum IgM antibodies against GnRH1, progonadoliberin-2, and GnRH receptors have been described in patients with signs and symptoms of gastrointestinal dysmotility and/or autonomic dysfunction, such as irritable bowel syndrome, enteric dysmotility, diabetes mellitus, and primary Sjögren's syndrome. Thus, apart from regulation of reproduction and sex hormone secretion, GnRH also constitutes a part of enteric nervous system (ENS) and its functions during physiological and pathological conditions. This review aimed to describe the role of GnRH in the ENS.