GnRH Receptor Research Articles

Postnatal Development and Maintenance of Functional Pituitary Gonadotrophs Is Dependent on PI4-Kinase A.

Postnatal development of functional pituitary gonadotrophs is necessary for maturation of the hypothalamic-pituitary-gonadal axis, puberty, and reproduction. Here we examined the role of PI4-kinase A, which catalyzes the biosynthesis of PI4P in mouse reproduction by knocking out this enzyme in cells expressing the gonadotropin-releasing hormone (GnRH) receptor. Knockout (KO) mice were infertile, reflecting underdeveloped gonads and reproductive tracts and lack of puberty. The number and distribution of hypothalamic GnRH neurons and Gnrh1 expression in postnatal KOs were not affected, whereas Kiss1/kisspeptin expression was increased. KO of PI4-kinase A also did not alter embryonic establishment and neonatal development and function of the gonadotroph population. However, during the postnatal period, there was a progressive loss of expression of gonadotroph-specific genes, including Fshb, Lhb, and Gnrhr, accompanied by low gonadotropin synthesis. The postnatal gonadotroph population also progressively declined, reaching approximately one-third of that observed in controls at 3 months of age. In these residual gonadotrophs, GnRH-dependent calcium signaling and calcium-dependent membrane potential changes were lost, but intracellular administration of inositol-14,5-trisphosphate rescued this signaling. These results indicate a key role for PI4-kinase A in the postnatal development and maintenance of a functional gonadotroph population.

Patient adherence and early biochemical outcomes following relugolix with stereotactic body radiation therapy (SBRT) for unfavorable prostate cancer.

526 Background: Prostate SBRT offers an abbreviated treatment course with comparable efficacy to conventional radiotherapy. Injectable GnRH receptor agonists have been shown to improve cancer control when combined with radiotherapy. Relugolix is a new oral GnRH receptor antagonist which achieves rapid, sustained testosterone suppression. This prospective study sought to evaluate early testosterone suppression and PSA response following Relugolix and SBRT for unfavorable prostate cancer. Methods: This prospective study sought to evaluate early testosterone suppression and PSA response following Relugolix and SBRT for unfavorable prostate cancer. Relugolix was initiated at least 2 months prior to SBRT. PSA and total testosterone levels were obtained prior to and 1-4 months post SBRT. Profound castration was defined as serum testosterone < 20 ng/dL. Poor drug adherence was delineated as failure to reach profound castration. PSA nadir was defined as the lowest PSA value within 4 months of completion of SBRT. Per prior trials, we examined the percentage of patients who achieved PSA level of ≤ 0.5 ng/mL and < 0.2 ng/mL during the first 4 months post SBRT. Results: Between July 2021 and January 2023, 52 men were treated at Georgetown with Relugolix (4-6 months) and SBRT (36.25-40 Gy in 5 fractions) per an institutional protocol (IRB 12-1775). Median age was 71 years. 26.9% of patients were black and 28.8% were obese (BMI ≥30 kg/m2). The median pretreatment PSA was 9.1 ng/ml. 67% of patients were > Grade Group 3. 44 patients were intermediate- and 8 were high-risk. The disease volume was high (mean 43.6% of total cores involved). Patients initiated Relugolix at a median of 3.6 months prior to SBRT with a median of 6.2 total months. 92.3%of patients achieved profound castration during Relugolix treatment. Poor drug adherence was observed in 2 patients. A third patient chose to discontinue Relugolix due to side effects. By post-SBRT month 4, 87.2% and 74.4% of patients achieved PSA levels ≤ 0.5 ng/ml and ≤ 0.2 ng/ml, respectively. Conclusions: Relugolix combined with SBRT allows for high rates of profound castration with low early PSA nadirs. Given the potential benefits of Relugolix over injectable GnRH receptor agonists, its usage may be preferred, especially in specific patient populations (fear of needles, prior cardiovascular events). We observed a 96% compliance rate without the utilization of scheduled cues/reminders. This finding supports the notion that patients can consistently and successfully follow an oral ADT protocol in a real-world setting. Future studies should focus on barriers to medication access.

Molecular characterization of gonadotropin-releasing hormone receptor and its expression profiling in response to HCG stimulation in striped murrel, Channa striata (Bloch, 1793)

The gonadotropin releasing hormone receptors (GnRHR) play an important role in the activation of GnRH and elicit the release of gonadotropins that plays an important role in maturation and spawning. In the present work, molecular characterization of the GnRHR gene of snakehead murrel, Channa striata was carried out. The full-length cDNA of GnRH receptors of the 1581 bp sequence, which encodes 440 amino acids was identified by RACE-PCR. Signal peptide analysis confirmed that GnRHR is a non-secretory protein, and hydropathy profiles indicated its hydrophobic nature. The deduced amino acid sequences of the GnRHR showed the expected conserved domains, which include seven membrane-spanning domains, two potential N-linked glycosylation sites (631 Asp, 561 Asp), and 32 sites phosphorylation sites of serine and threonine residues. A homology search of GnRHR cDNA sequence revealed 88 % identity with Channa argus, followed by 85 % and 83 % sequence identities with Lates calcarifer, and Anabas testudineus at the protein level. Phylogenetic analysis depicted a close association with Channa argus and other fish species. Our findings showed differential GnRHR expression during different reproductive stages, with higher expression after HCG administration. Expression profiling revealed that GnRHR is highly expressed in the brain and testis at 16 h post-HCG injection, while it was neutrally regulated in female ovarian tissues. This study provides full-length coding sequence information of the GnRHR gene and will help to understand the reproductive biology of murrel using expression studies and devise strategies for induced breeding.

GV1001 modulates neuroinflammation and improves memory and behavior through the activation of gonadotropin-releasing hormone receptors in a triple transgenic Alzheimer’s disease mouse model

GV1001 protects neural cells from amyloid-β (Aβ) toxicity and other stressors in in vitro studies and demonstrates clinically beneficial effects in patients with moderate to severe Alzheimer’s disease (AD). Here, we investigated the protective effects and mechanism of action of GV1001 in triple transgenic AD (3xTg-AD) mice. We found that GV1001 improved memory and cognition in middle- and old-aged 3xTg-AD mice. Additionally, it reduced Aβ oligomer and phospho-tau (Ser202 and Thr205) levels in the brain, and mitigated neuroinflammation by promoting a neuroprotective microglial and astrocyte phenotype while diminishing the neurotoxic ones. In vitro, GV1001 bound to gonadotropin releasing hormone receptors (GnRHRs) with high affinity. Levels of cyclic adenosine monophosphate, a direct downstream effector of activated GnRHRs, increased after GV1001 treatment. Furthermore, inhibition of GnRHRs blocked GV1001-induced effects. Thus, GV1001 might improve cognitive and memory functions of 3xTg-AD mice by suppressing neuroinflammation and reducing Aβ oligomers levels and phospho-tau by activating GnRHRs and their downstream signaling pathways.

Early biochemical outcomes following neoadjuvant/adjuvant relugolix with stereotactic body radiation therapy for intermediate to high risk prostate cancer.

Injectable GnRH receptor agonists have been shown to improve cancer control when combined with radiotherapy. Prostate SBRT offers an abbreviated treatment course with comparable efficacy to conventionally fractionated radiotherapy. Relugolix is a new oral GnRH receptor antagonist which achieves rapid, sustained testosterone suppression. This prospective study sought to evaluate early testosterone suppression and PSA response following relugolix and SBRT for intermediate to high prostate cancer. Relugolix was initiated at least 2 months prior to SBRT. Interventions to improve adherence were not utilized. PSA and total testosterone levels were obtained prior to and 1-4 months post SBRT. Profound castration was defined as serum testosterone ≤ 20 ng/dL. Early PSA nadir was defined as the lowest PSA value within 4 months of completion of SBRT. Per prior trials, we examined the percentage of patients who achieved PSA level of ≤ 0.5 ng/mL and ≤ 0.2 ng/mL during the first 4 months post SBRT. Between July 2021 and January 2023, 52 men were treated at Georgetown with relugolix (4-6 months) and SBRT (36.25-40 Gy in 5 fractions) per an institutional protocol (IRB 12-1775). Median age was 71 years. 26.9% of patients were African American and 28.8% were obese (BMI ≥30 kg/m2). The median pretreatment PSA was 9.1 ng/ml. 67% of patients were ≥ Grade Group 3. 44 patients were intermediate- and 8 were high-risk. Patients initiated relugolix at a median of 3.6 months prior to SBRT with a median duration of 6.2 total months. 92.3% of patients achieved profound castration during relugolix treatment. Poor drug adherence was observed in 2 patients. A third patient chose to discontinue relugolix due to side effects. By post-SBRT month 4, 87.2% and 74.4% of patients achieved PSA levels ≤ 0.5 ng/ml and ≤ 0.2 ng/ml, respectively. Relugolix combined with SBRT allows for high rates of profound castration with low early PSA nadirs. We observed a 96% testosterone suppresion rate without the utilization of scheduled cues/reminders. This finding supports the notion that patients with localized prostate cancer can consistently and successfully follow an oral ADT protocol without daily reminders. Given relugolix's potential benefits over injectable GnRH receptor agonists, its usage may be preferred in specific patient populations (fear of needles, prior cardiovascular events). Future studies should focus on boundaries to adherence in specific underserved populations.

Withaferin-A attenuates diabetes mellitus induced male reproductive dysfunction mediated by ERα in brain and testes of Swiss albino mice

Diabetes mellitus (DM) is a chronic metabolic disease, characterized by persistent hyperglycemia resulting from diminished insulin secretion or insulin resistance. The present study evaluated the ameliorative effects of Withaferin-A (WA) on DM-induced reproductive dysfunction in mice. For the same, mice were intraperitoneally injected with Streptozotocin (STZ), (40 mg/kg/day) for 5 consecutive days to induce DM. Mice were then treated with WA (8 mg/kg/day) in normal and diabetic conditions (STZ + WA). Next, blood glucose levels, oral glucose tolerance, intraperitoneal insulin tolerance, oxidative stress and reproductive parameters were estimated. For reproductive performance, immunofluorescent localization of gonadotropin-releasing hormone (GnRH-I) and estrogen receptor alpha (ERα) in the preoptic area and paraventricular nucleus region of hypothalamus and ERα in testes was performed. STZ-induced diabetes triggered reproductive dysfunctions as mediated by low GnRH-I and ERα in the brain and ERα in the testes along with declined testosterone and estradiol levels. Treatment with WA significantly reduced the blood glucose levels and enhanced glucose clearance accompanied by reduced oxidative stress in the brain, pancreas and testes as indicated by the low levels of H2O2 and MDA in diabetic mice treated with WA (STZ + WA). This study reports, for the first time, that WA can efficiently ameliorate DM-induced reproductive dysfunctions by enhancing endogenous testosterone, estrogen and increased GnRH-I and ERα in the brain and ERα in the testes of DM-induced male mice.

Rational Design, Synthesis and Binding Affinity Studies of Anthraquinone Derivatives Conjugated to Gonadotropin-Releasing Hormone (GnRH) Analogues towards Selective Immunosuppression of Hormone-Dependent Cancer.

Gonadotropin-releasing hormone (GnRH) is pivotal in regulating human reproduction and fertility through its specific receptors. Among these, gonadotropin-releasing hormone receptor type I (GnRHR I), which is a member of the G-protein-coupled receptor family, is expressed on the surface of both healthy and malignant cells. Its presence in cancer cells has positioned this receptor as a primary target for the development of novel anti-cancer agents. Moreover, the extensive regulatory functions of GnRH have underscored decapeptide as a prominent vehicle for targeted drug delivery, which is accomplished through the design of appropriate conjugates. On this basis, a rationally designed series of anthraquinone/mitoxantrone-GnRH conjugates (con1-con8) has been synthesized herein. Their in vitro binding affinities range from 0.06 to 3.42 nM, with six of them (con2-con7) demonstrating higher affinities for GnRH than the established drug leuprolide (0.64 nM). Among the mitoxantrone based GnRH conjugates, con3 and con7 show the highest affinities at 0.07 and 0.06 nM, respectively, while the disulfide bond present in the conjugates is found to be readily reduced by the thioredoxin (Trx) system. These findings are promising for further pharmacological evaluation of the synthesized conjugates with the prospect of performing future clinical studies.

AXL receptor tyrosine kinase modulates gonadotropin-releasing hormone receptor signaling

BackgroundGonadotropin-releasing hormone (GnRH) receptors are essential for reproduction and are expressed in numerous urogenital, reproductive, and non-reproductive cancers. In addition to canonical G protein-coupled receptor signaling, GnRH receptors functionally interact with several receptor tyrosine kinases. AXL is a receptor tyrosine kinase expressed in numerous tissues as well as multiple tumors. Here we tested the hypothesis that AXL, along with its endogenous ligand Gas6, impacts GnRH receptor signaling.MethodsWe used clonal murine pituitary αT3-1 and LβT2 gonadotrope cell lines to examine the effect of AXL activation on GnRH receptor-dependent signaling outcomes. ELISA and immunofluorescence were used to observe AXL and GnRH receptor expression in αT3-1 and LβT2 cells, as well as in murine and human pituitary sections. We also used ELISA to measure changes in ERK phosphorylation, pro-MMP9 production, and release of LHβ. Digital droplet PCR was used to measure the abundance of Egr-1 transcripts. A transwell migration assay was used to measure αT3-1 and LβT2 migration responses to GnRH and AXL.ResultsWe observed AXL, along with the GnRH receptor, expression in αT3-1 and LβT2 gonadotrope cell lines, as well as in murine and human pituitary sections. Consistent with a potentiating role of AXL, Gas6 enhanced GnRH-dependent ERK phosphorylation in αT3-1 and LβT2 cells. Further, and consistent with enhanced post-transcriptional GnRH receptor responses, we found that Gas6 increased the abundance of Egr-1 transcripts. Suggesting functional significance, in LβT2 cells, Gas6/AXL signaling stimulated LHβ production and enhanced GnRH receptor-dependent generation of pro-MMP9 protein and promoted cell migration.ConclusionsAltogether, these data describe a novel role for AXL as a modulator of GnRH receptor signaling.5LYCavpivq5eiBQqEyV1BjVideo

Impact of Relugolix Versus Leuprolide on the Quality of Life of Men with Advanced Prostate Cancer: Results from the Phase 3 HERO Study

BackgroundRelugolix, an oral gonadotropin-releasing hormone receptor antagonist, demonstrated testosterone suppression to castrate levels in men with advanced prostate cancer (PCa) in the HERO study. Since advanced PCa and its treatments can impact patients’ daily life, it is imperative to understand the impact of systemic therapy on patient health-related quality of life (HRQOL). ObjectiveTo report the HRQOL for patients on relugolix compared with those on leuprolide in on-treatment and testosterone recovery periods of the HERO study. Design, setting, and participantsA phase 3 randomized controlled study was conducted in 934 patients with advanced PCa. InterventionPatients underwent 2:1 randomization and received relugolix 120 mg orally once daily or leuprolide 3-mo injections for 48 wk. Testosterone recovery was evaluated in a patient subset. Outcome measurements and statistical analysisHRQOL evaluations were based on the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (EORTC QLQ-C30) and the Prostate Cancer Module (EORTC QLQ-PR25) during treatment and testosterone recovery phases. In a post hoc analysis, predictors of HRQOL deterioration were evaluated. Results and limitationsNo statistically significant differences between the two groups were found in changes from baseline to the end of treatment in either the EORTC QLQ-C30 or the EORTC QLQ-PR25 instrument. During the testosterone recovery phase, hormonal treatment–related symptoms scores were lower for relugolix than for leuprolide, suggesting a lower burden of hormone-related symptoms associated with a treatment that has more rapid testosterone recovery after treatment cessation. Limitations include low patient numbers in the testosterone recovery group. ConclusionsOral relugolix is a therapeutic option with similar patient-reported HRQOL to leuprolide, providing an oral option for androgen deprivation therapy associated with a more rapid testosterone reduction. Patient summaryIn men with advanced prostate cancer, relugolix had similar health-related quality of life to leuprolide.

Therapeutic dosing and targeting efficacy of Pt-Mal-LHRH towards triple negative breast cancer.

Pt-Mal-LHRH is a newly synthesized chemotherapeutic agent that was designed to selectively target the luteinizing hormone-releasing hormone (LHRH) receptor expressed by triple negative breast cancer (TNBC). The aim of this study was to evaluate the therapeutic dosing, tumor reduction efficacy, and selective distribution of Pt-Mal-LHRH in-vivo. LHRH tissue expression levels in-vivo were investigated using western blotting and LHRH was found to be increased in reproductive tissues (mammary, ovary, uterus). Further, Pt-Mal-LHRH was found to have increased TNBC tumor tissue platinum accumulation compared to carboplatin by inductively coupled plasma mass spectrometry analysis. The platinum family, compound carboplatin, was selected for comparison due to its similar chemical structure and molar equivalent doses were evaluated. Moreover, in-vivo distribution data indicated selective targeting of Pt-Mal-LHRH by enhanced reproductive tissue accumulation compared to carboplatin. Further, TNBC tumor growth was found to be significantly attenuated by Pt-Mal-LHRH compared to carboplatin in both the 4T1 and MDA-MB-231 tumor models. There was a significant reduction in tumor volume in the 4T1 tumor across Pt-Mal-LHRH doses (2.5-20 mg/kg/wk) and in the MDA-MB-231 tumor at the dose of 10 mg/kg/wk in models conducted by an independent contract testing laboratory. Our data indicates Pt-Mal-LHRH is a targeting chemotherapeutic agent towards the LHRH receptor and reduces TNBC tumor growth in-vivo. This study supports drug conjugation design models using the LHRH hormone for chemotherapeutic delivery as Pt-Mal-LHRH was found to be a more selective and efficacious than carboplatin. Further examination of Pt-Mal-LHRH is warranted for its clinical use in TNBCs, along with, other reproductive cancers overexpressing the LHRH receptor.

FRI290 Proteomic Identification Of Secretoneurin-Stimulated Proteins In Purified Mouse Gonadotropes

Abstract Disclosure: A. Herdman: None. A. Lagasse: None. A. Haney: None. S. Byrum: None. U. Boehm: None. M.C. MacNicol: None. A.M. MacNicol: None. G.V. Childs: None. A.K. Odle: None. Secretoneurin (SN) is a proteolytic product of secretogranin II (SCG2), a member of the granin family of proteins. Both SCG2 and SN have been localized in the anterior pituitary (AP), and SCG2 co-localizes to gonadotrope granules containing luteinizing hormone (LH). Preliminary studies from others have shown that exogenous SN is capable of stimulating LH secretion from the mouse LßT2 cell line and goldfish pituitaries, and SN may provide a paracrine signal from other AP cells to support LH production/secretion. Despite the implications for regulatory reproductive signaling, a comprehensive study of the effect of SN on female mammalian gonadotropes has not been conducted. To define the pathways and processes affected by exogenous secretoneurin (SN) on murine gonadotrope protein expression, pituitaries from 18 proestrous female mice expressing Gnrhr-driven Cre and a floxed fluorescent Cre reporter were collected and dispersed. Half of the dispersed pituitaries were stimulated with 1 μM SN, and all cells were incubated for 3 hours. Gonadotropes were purified via fluorescence-activated cell sorting. After pooling to optimize cell counts, control and SN-stimulated gonadotropes were submitted for mass-spectrometry proteomics. A differential expression analysis was performed to determine fold-change (FC) in proteins from SN-stimulated samples over control (unstimulated), and false discovery rate (FDR)-controlled adjusted p values were used to assign significance (Adj p≤0.05). A total of 948 proteins were identified in the purified gonadotrope pools. Of these, 136 proteins were significantly differentially expressed between control and SN-stimulated gonadotrope pools; 53 proteins were upregulated and 83 were downregulated in SN-stimulated gonadotropes. Upregulated targets of particular interest include the SN precursor SCG2 (FC = 12, p<0.05), as well as prohormone convertase 2 (PC2: FC = 8, p<0.05) which can cleave SCG2 to produce SN. Also upregulated is ELAV-like protein 1 (ELAVL1: FC=5, p<0.05), an RNA-binding protein known to regulate gonadotropin-releasing hormone receptor (GnRHR) expression and bind other gonadotrope-critical mRNAs. Although LHß was unchanged, the glycoprotein alpha subunit (CGA) was decreased 4-fold following SN stimulation (p = 0.05). This is consistent with previous reports showing decreased Cga mRNA following SN stimulation. In addition to the expected “cell signaling” and “response to stimulation”, gene ontology analysis showed that the major biological processes altered by SN stimulation include processing of RNA (including RNA binding, translation regulation, etc.) and regulation of cell structure. Indeed, several RNA-binding proteins and actin-related proteins were significantly changed. Our data confirm previous results from LßT2 cells and define new SN targets and pathways that may play a broader role in gonadotrope physiology. Presentation: Friday, June 16, 2023

THU580 A Subset Of Migrating Cells Co-express Gonadotropin Releasing Hormone And Prokineticin Receptor 2 During Embryonic Development

Abstract Disclosure: A.E. Danku: None. C.F. Elias: None. A subset of migrating cells co-express gonadotropin releasing hormone and prokineticin receptor 2 during embryonic development Antoinette Danku and Carol F Elias. Neuroscience Graduate Program and Department of Molecular & Integrative Physiology, University to Michigan. Reproductive vitality in humans is strongly influenced by developmental foundations. The successful migration of GnRH cells and the pulsatile secretion of gonadotropin releasing hormone (GnRH) drives pubertal onset and dictates long-term fertility outcomes. During development, GnRH neurons migrate from the nasal placode to the basal forebrain to reach their destination in the medial preoptic area (MPOA). Aberrant GnRH migration causes redirection of axonal projections to atypical brain regions and dysregulated GnRH secretion. Disruption of GnRH neuronal function causes infertility or reproductive dysfunction. These etiologies are grouped as isolated gonadotropin deficiencies (IGD). Kallmann’s syndrome (KS) is a pediatric IGD that manifests as anosmia and hormonal dysfunction that can result in pubertal delay or infertility. Children with KS often have mutations in prokineticin 2 (Prok2) or the cognate receptor (ProkR2).Prok2 and ProkR2 are required for the formation of the olfactory bulb in rodents and humans. Loss-of-function mutations in these genes also disrupts GnRH cell migration, but whether the activation of ProkR2 regulates the guidance of GnRH neurons to their final destination has not been defined. Previous studies suggested that GnRH and ProkR2 are expressed in distinct cells, but how the prokineticin system may alter GnRH migration is largely unknown. To gain insights into the underlying mechanisms associated with ProkR2-GnRH interaction and migration, we conducted single nuclei RNA sequencing in nasal-forebrain junction of embryos at embryonic day 16 (E16) and fluorescent in situ hybridization in three developmental time points: E14, E16, and E18 for validation and spatial evaluation. Using these methods, we were able to isolate GnRH and ProkR2 cells and sort their cell types into clusters. While these cells differ in their expression profiles, they both express genes associated with migration at E16. Our findings suggest that ProkR2 cells in the nasal-forebrain junction migrate along with GnRH cells. Additionally, a subset of these migrating cells co-express ProkR2 and GnRH mRNA. Further studies are needed to determine whether this subset of cells take on specialized roles in GnRH cell migration and maturation. Presentation: Thursday, June 15, 2023

SAT591 Abnormal Levels Of Thyroid Hormones During Development Alters The Migration And Activity Of GnRH Reproductive Neurons

Abstract Disclosure: C. Quignon: None. A. Backer: None. S. Wray: None. Clinical studies have shown that thyroid hormones disorders and alteration of thyroid hormone production by environmental endocrine disruptors, have deleterious effects on reproduction. By acting in the brain on the hypothalamic component of the reproductive axis, abnormal levels of thyroid hormones can disturb sex hormones production, oestrus cycles or puberty onset, possibly leading to subfertility. Moreover, in animal models, endocrine disruptors and thyroid hormones have been shown to have long-lasting transgenerational effects with the maternal hormones influencing the development of foetal reproductive functions. Despite clear evidence of an interaction between the thyroid and reproductive systems, the effect of T3, the active form of thyroid hormones, on the GnRH neurons controlling reproduction, have been poorly studied. In this work we investigated how T3 functionally interacts with GnRH neurons and how abnormal concentration of T3 alters the migration of these neurons during development. Calcium imaging was used to study the direct effect of T3 on GnRH neuronal activity in an ex vivo nasal explants model. Acute administration of T3 (30nM) was found to stimulate the activity of GnRH cells. Dual labelling of GnRH and thyroid hormone receptors (TR) showed that the GnRH neurons express both nuclear and membrane receptors. However, the use of an antagonist that specifically blocks the TR nuclear receptors (1-850), didn’t inhibit the T3 stimulatory effect. In contrast, blockage of integrin αV/β3 membrane receptors (with cilengitide), which have been shown to be activated by T3, prevented the T3-induced increase in GnRH neuronal activity. During development GnRH neurons migrate from the nasal placodes into the brain. Acute administration of T3 for 1hr significatively decreased the migration rate of the GnRH neurons in our ex vivo model. To assess the effect of thyroid disruption during pregnancy on the development of reproductive axis in utero, pregnant females mice have been treated with methimazole to induce hypothyroidism from gestational day 6 to 13. E13 embryos have been collected from treated and control dams and the distribution of migrating GnRH neurons will be compared between both groups. Together these studies are the first to report a direct effect of thyroid hormones on GnRH neuronal activity, through the integrin αV/β3 membrane receptors and show that T3 can modulate the migration of GnRH neurons during development. These results will bring new insights on how thyroid disruption by endocrine disruptor chemicals or thyroid diseases, especially during foetal development, can lead to long term reproductive defects. Presentation: Saturday, June 17, 2023

SAT606 Comparison Of Psychosocial And Immune/Inflammatory Stress On Luteinizing Hormone Pulsatile Secretion

Abstract Disclosure: J. Jang: None. M.J. Kreisman: None. K.M. Breen Church: None. Stress induces a physiological response in the body to return to the homeostatic state. It is recognized that many stress types impair reproduction, but the mechanisms conveying inhibition may be distinct and stressor-dependent. Our research aims to understand how stress inhibits the neuroendocrine mechanisms controlling the pulsatile release of luteinizing hormone (LH). This is especially important because pulsatile LH is pivotal to reproductive health in males and females. Immune/inflammatory stressors such as lipopolysaccharides (LPS) cause an inflammatory response, producing peripheral cytokines that can signal to the brain in distinct ways compared to the neural mechanisms employed in response to psychosocial stress. However, how LPS disrupts the neural mechanisms involved in gonadotropin pulsatility is still unknown. Here, we compared the alteration in LH pulses in response to psychosocial restraint stress or immune/inflammatory LPS stress and sought to understand stress-specific regulation of the upstream targets controlling LH synthesis and secretion. Our initial observations demonstrated, in ovariectomized (OVX) female mice, that restraint stress elicited suppression rapidly, within 30 minutes; yet, the response to LPS was delayed, occurring approximately 90 minutes from injection. Therefore, we investigated the prolonged response of the stressors on LH pulses, observing LH pulse profiles 90 minutes to 180 minutes after the initiation of stress. Restraint stress significantly suppressed mean LH, resulting from a suppression of pulse frequency. LPS injected intraperitoneal (IP, 1.5 ug/g) also significantly suppressed mean LH. In contrast to restraint stress, LPS induced a reduction in both frequency as well as LH pulse amplitude. We conducted two follow-up experiments to investigate the lowered LH pulse amplitude during immune/inflammatory stress. The first study assessed hypothalamic kisspeptin gene expression and pituitary LHβ and GnRH receptor expression, in LPS versus restraint animals, to test whether altered gene transcription in LPS animals resulted in lowered LH secretion. The results of this experiment are still pending. The second study tested the LH response to a single bolus of GnRH or kisspeptin. Interestingly, we found equivalent LH increases, to either agonist, in saline versus LPS-treated animals. Collectively, these data indicate that both restraint and immune/inflammatory stress inhibit LH pulse frequency. However, the endogenous LH pulse profiles suggest an additional stressor-specific mechanism that lowers pulsatile LH during immune/inflammatory stress via LPS. Identification of stress pathways that alter endocrine hormones is critical as it allows for the development of therapeutics and medications to treat endocrine disorders. Presentation: Saturday, June 17, 2023

FRI311 GnRH Agonist Induced Pituitary Apoplexy In A Patient With Gonadotropinoma

Abstract Disclosure: I. Madahar: None. S. Khan: None. L. Hergenroeder: None. B. Skaff: None. A. Haider: None. Introduction: GnRH therapy is commonly employed in patients with advanced prostate cancer. It acts as an agonist that binds to pituitary GnRH receptors. It acts via desensitization, downregulating FSH and LH production, and ultimately decreasing testicular steroidogenesis. Initial administration leads to transient stimulation of the pituitary which leads to elevated FSH and LH levels and increased production of estrogen and testosterone with eventual downregulation of the overall pathway. Case description: 80-year-old male with a past history of atrial fibrillation and OA was diagnosed with prostate cancer. Prostate adenocarcinoma Gleason score 7 (4+3) grade 3 was diagnosed by needle core biopsy five months prior to presentation. CT chest, abdomen, pelvis, and bone scan did not show evidence of metastatic disease. A week prior to starting Lupron therapy he was started on bicalutamide therapy. He received a dose of leuprolide (Elligard) as part of his chemoradiation therapy for his cancer. The patient went golfing after the treatment and within four hours he started noticing headaches and retroorbital pain. Headaches were sharp in quality, intensity 9 out of 10, and associated with nausea and vomiting. He later developed right-sided ptosis and double vision which progressively worsened after the next few hours. An initial CT scan of the head showed an enlarging pituitary mass which was followed MRI of the brain with and without contrast showed an enlarged pituitary mass and right cavernous sinus effacement of the optic chiasm. Anterior pituitary hormone functions were ordered, and the patient was started on stress-dose steroids. Transsphenoidal pituitary resection was done which the patient tolerated well pathology showed pituitary adenoma with pituitary apoplexy and the immunoprofile was compatible with gonadotroph adenoma. The adenoma cells were positive for synaptophysin, cam 5.2, GATA3, and FSH. A repeat MRI of the Sella three months after surgery showed a 9 mm nodule in the right aspect of the Sella. Anterior pituitary hormone levels done prior to surgery showed an IGF- 1 level of 204 ng/ml (Z score 1.5 SD). TSH and free T4 were in the normal range. Hydrocortisone was tapered and stopped 6 weeks after transsphenoidal surgery. Discussion: Lupron levels reach maximum concentration four hours after intramuscular administration. Initial pituitary stimulation by leuprolide administration causes the increased metabolic activity of the underlying adenoma which outgrows its blood supply, thus developing ischemic necrosis and subsequent hemorrhage. The majority of pituitary apoplexy develops in patients with previous undiagnosed pituitary adenomas. Should patients get central imaging to screen for pituitary macroadenoma before Lupron treatments to prevent this potentially life-threatening complication? Presentation: Friday, June 16, 2023

Relugolix vs. Leuprolide Effects on Castration Resistance-Free Survival from the Phase 3 HERO Study in Men with Advanced Prostate Cancer.

Background: Relugolix is an oral GnRH receptor antagonist approved for men with advanced prostate cancer. Relugolix treatment has demonstrated an ability to lower testosterone to sustained castration levels in the phase 4 HERO study. Herein, we describe the results of a secondary endpoint of castration resistance-free survival (CRFS) during 48 weeks of treatment and profile patients with castration-resistant prostate cancer (CRPC). Methods: Subjects were 2:1 randomized to either relugolix 120 mg orally once daily (after a single 360 mg loading dose) or 3-monthly injections of leuprolide for 48 weeks. CRFS, defined as the time from the date of first dose to the date of confirmed prostate-specific antigen progression while castrated or death due to any reason was conducted in the metastatic disease population and the overall modified intention-to-treat (mITT) populations. Results: The CRFS analysis (mITT population) included 1074 men (relugolix: n = 717; leuprolide: n = 357) with advanced prostate cancer as well as 434 men (relugolix: n = 290; leuprolide: n = 144) with metastatic prostate cancer. In the metastatic disease populations, CRFS rates were 74.3% (95% CI: 68.6%, 79.2%) and 75.3% (95% CI: 66.7%, 81.9%) in the relugolix and leuprolide groups, respectively (hazard ratio: 1.03 [0.68, 1.57]; p = 0.84) at week 48. Results in the overall mITT population were similar to the metastatic population. No new safety findings were identified. Conclusions: In men with metastatic disease or in the overall population of the HERO study, CRFS assessed during the 48-week treatment with relugolix was not significantly different than standard-of-care leuprolide. Relugolix had similar efficacy for men with/without CRFS progression events.

OR09-01 Mini-Puberty Could Be A Key Phase Regulating Reproductive Function In Female Mice

Abstract Disclosure: M. Chester: None. M. Devillers: None. L. Naule: None. F. Souaré: None. R. Corre: None. D. Quintas: None. C. Petrovic: None. J. Cohen-Tannoudji: None. S. Mhaouty-Kodja: None. C.J. Guigon: None. After birth, there is a transient activation of the hypothalamic-pituitary-ovary (HPO) axis, with high secretion of LH and FSH acting on the ovary to promote the secretion of sex steroids and in particular that of estradiol (E2). This period, called mini-puberty, occurs between 10-17 days postnatal (dpn) in mice. During reproductive life, E2 plays an important role on the HPO axis by regulating GnRH pulsatility and, thus, the cyclic fluctuations of gonadotropin hormone levels required for follicular development and ovulation. E2 acts on hypothalamic kisspeptin neurons of the arcuate (ARC) and the anteroventral periventricular nucleus (AVPV), which project to GnRH neurons and regulate their activity by negative and positive feedbacks, respectively. The possibility that E2 contributes, during mini-puberty, to the maturation of hypothalamic structures involved in puberty onset and reproductive function, has never been investigated. The aim of this study was to elucidate the putative roles of mini-puberty on reproduction. We developed a mouse model injected with a GnRH receptor antagonist (GonadoSTOP mice) suppressing LH and FSH surges to cause a 50% decrease in E2 levels during mini-puberty. Our results show that GonadoSTOP mice exhibited later first diestrus 2 (D2) (31.0 dpn versus 29.9 dpn in CTR; n=55-56 mice/group; P=0.0285), suggesting a possible delay in the timing of puberty. During reproductive life, GonadoSTOP mice spent a longer % of time in D2 than control mice, with no alteration in total estrous cycle time (64.4% versus 56% in CTR; n=18-19 mice/group; P=0.0350). Immunohistochemical analysis of kisspeptin neurons in ARC and AVPV of ovariectomized and hormonally-primed mice showed that their numbers were significantly lower in AVPV from GonadoSTOP mice than in control mice (n=5-6 brains/group; P=0.038). In fertility studies, we observed no difference in the time to conception or % of pregnant mice between the two groups at early reproductive life (3, 4 and 5 months). Contrary to these results, at the time of reproductive decline in control mice (11 months), a substantial % of GonadoSTOP mice could still be pregnant (47% versus 18% of CTR mice; P=0.0017). At this age, GonadoSTOP mice had lower LH levels than control mice (P=0.0074), but similar levels to young control mice at 4 months (P>0.05). RT-qPCR analyses of markers reflecting ovarian activity (Cyp19a1, Inhbb, Amh, Gdf9) at 4 and 11 months revealed that ovarian aging occurred similarly in both groups, suggesting that reproductive longevity in GonadoSTOP mice does not have an ovarian origin. Taken together these data suggest that transient and sustained activation of the HPO axis at mini-puberty may regulate key aspects of reproductive function with long-term impact on fertility, possibly by acting on the hypothalamus. Presentation: Friday, June 16, 2023

Relugolix, Estradiol, Norethindrone Acetate (40mg+1.0mg+0.5mg), Oral Combination Therapy for Uterine Fibroids (Relugolix) in Premenstrual Women: A Quality Life Perspective

The following article elucidates the role of oral therapy for uterine fibroids in increasing the quality of life and a better treatment option as compared to the conventional methods, which are operative and may result in infertility. Uterine fibroids are non-cancerous growths (myomas or leiomyomas) also known as Uterine Leiomyomas or Fibromyomas appear in or around the uterus. They can shrink after menopause, exist in adults of reproductive age, and have been connected to oestrogen, however the specific origin is unknown. Uterine fibroids affect about 1 in 3 women, and their prevalence rises with age until menopause, peaking in the forties. In general, symptoms can be categorized as heavy and protracted menstrual bleeding, pelvic pain, and reproductive dysfunction. The triple combination drug is given orally to the patients (once daily as early as possible after menstrual cycle but no later than seven days after menstrual cycle begins) and it can be given for the period of 24 months which is longer duration than its other alternatives like leuprolide (6-12 months) and it effectively resolves Abnormal Uterine Bleeding – Leiomyomata (AUB-L). It will resolve the imbalance of estrogen and progesterone in female body and reduces the side effects such as bone loss due to estrogen imbalance. Being an oral tablet gives it an advantage over other surgical procedures and parenteral dosage forms as it is non-invasive and easy to administer, in small dose, once daily. Keywords: Uterine Fibroids, Health Related Quality of Life, Gonadotropin Releasing Hormone Receptor Antagonist, Combination Therapy, Relugolix.

Functional Characterization of Gonadotropin-Releasing Hormone and Corazonin Signaling Systems in Pacific Abalone: Toward Reclassification of Invertebrate Neuropeptides

Introduction: The proposed evolutionary origins and corresponding nomenclature of bilaterian gonadotropin-releasing hormone (GnRH)-related neuropeptides have changed tremendously with the aid of receptor deorphanization. However, the reclassification of the GnRH and corazonin (CRZ) signaling systems in Lophotrochozoa remains unclear. Methods: We characterized GnRH and CRZ receptors in the mollusk Pacific abalone, Haliotis discus hannai (Hdh), by phylogenetic and gene expression analyses, bioluminescence-based reporter, Western blotting, substitution of peptide amino acids, in vivo neuropeptide injection, and RNA interference assays. Results: Two Hdh CRZ-like receptors (Hdh-CRZR-A and Hdh-CRZR-B) and three Hdh GnRH-like receptors (Hdh-GnRHR1-A, Hdh-GnRHR1-B, and Hdh-GnRHR2) were identified. In phylogenetic analysis, Hdh-CRZR-A and -B grouped within the CRZ-type receptors, whereas Hdh-GnRHR1-A/-B and Hdh-GnRHR2 clustered within the GnRH/adipokinetic hormone (AKH)/CRZ-related peptide-type receptors. Hdh-CRZR-A/-B and Hdh-GnRHR1-A were activated by Hdh-CRZ (pQNYHFSNGWHA-NH₂) and Hdh-GnRH (pQISFSPNWGT-NH₂), respectively. Hdh-CRZR-A/-B dually coupled with the Gα_q and Gα_s signaling pathways, whereas Hdh-GnRHR1-A was linked only with Gα_q signaling. Analysis of substituted peptides, [I²S³]Hdh-CRZ and [N²Y³H⁴]Hdh-GnRH, and in silico docking models revealed that the N-terminal amino acids of the peptides are critical for the selectivity of Hdh-CRZR and Hdh-GnRHR. Two precursor transcripts for Hdh-CRZ and Hdh-GnRH peptides and their receptors were mainly expressed in the neural ganglia, and their levels increased in starved abalones. Injection of Hdh-CRZ peptide into abalones decreased food consumption, whereas Hdh-CRZR knockdown increased food consumption. Moreover, Hdh-CRZ induced germinal vesicle breakdown in mature oocytes. Conclusion: Characterization of Hdh-CRZRs and Hdh-GnRHRs and their cognate peptides provides new insight into the evolutionary route of GnRH-related signaling systems in bilaterians.

Novel Correlation between TGF-β1/-β3 and Hormone Receptors in the Human Corneal Stroma.

This study investigated the interplay between transforming growth factor beta (TGF-β1/T1 and TGF-β3/T3), and sex hormone receptors using our 3D in vitro cornea stroma model. Primary human corneal fibroblasts (HCFs) from healthy donors were plated in transwells at 106 cells/well and cultured for four weeks. HCFs were supplemented with stable vitamin C (VitC) and stimulated with T1 or T3. 3D construct proteins were analyzed for the androgen receptor (AR), progesterone receptor (PR), estrogen receptor alpha (ERα) and beta (ERβ), luteinizing hormone receptor (LHR), follicle-stimulating hormone receptor (FSHR), gonadotropin-releasing hormone receptor (GnRHR), KiSS1-derived peptide receptor (KiSS1R/GPR54), and follicle-stimulating hormone subunit beta (FSH-B). In female constructs, T1 significantly upregulated AR, PR, ERα, FSHR, GnRHR, and KiSS1R. In male constructs, T1 significantly downregulated FSHR and FSH-B and significantly upregulated ERα, ERβ, and GnRHR. T3 caused significant upregulation in expressions PR, ERα, ERβ, LHR, FSHR, and GNRHR in female constructs, and significant downregulation of AR, ERα, and FSHR in male constructs. Semi-quantitative Western blot findings present the interplay between sex hormone receptors and TGF-β isoforms in the corneal stroma, which is influenced by sex as a biological variable (SABV). Additional studies are warranted to fully delineate their interactions and signaling mechanisms.