Blocking FSH induces thermogenic adipose tissue and reduces body fat.

Menopause is associated with bone loss and enhanced visceral adiposity. A polyclonal antibody that targets the ß-subunit of the pituitary hormone follicle-stimulating hormone (Fsh) increases bone mass in mice. Here, we report that this antibody sharply reduces adipose tissue in wild-type mice, phenocopying genetic haploinsufficiency for the Fsh receptor gene Fshr. The antibody also causes profound beiging, increases cellular mitochondrial density, activates brown adipose tissue and enhances thermogenesis. These actions result from the specific binding of the antibody to the ß-subunit of Fsh to block its action. Our studies uncover opportunities for simultaneously treating obesity and osteoporosis.

Central residues of FSHß (89-97) peptide are not critical for FSHR binding: Implications for peptidomimetic design.

In our previous study, we had identified a 9-mer peptide (FSHß (89-97)) derived from seat belt loop of human FSHß and demonstrated its ability to function as FSHR antagonist in vivo. Structure analysis revealed that the four central residues 91STDC94 within this peptide may not be critical for receptor binding. In the present study, 91STDC94 residues were substituted with alanine to generate ΔFSHß 89-97(91STDC94/AAAA) peptide. Analogous to the parent peptide, ΔFSHß 89-97(91STDC94/AAAA) peptide inhibited binding of iodinated FSH to rat FSHR and reduced FSH-induced cAMP production. The peptide could impede granulosa cell proliferation leading to reduction in FSH-mediated ovarian weight gain in immature female rats. In these rats, peptide administration further downregulated androgen receptor and estrogen receptor-alpha expression and upregulated estrogen receptor-beta expression. The results indicate that substitution of 91STDC94 with alanine did not significantly alter FSHR antagonist activity of FSHß (89-97) peptide implying that these residues are not critical for FSH-FSHR interaction and can be replaced with non-peptidic moieties for development of more potent peptidomimetics.

FSH receptor binding inhibitor depresses carcinogenesis of ovarian cancer via decreasing levels of K-Ras, c-Myc and FSHR.

The present study aimed to explore FSH receptor binding inhibitor (FRBI) effects on the levels of c-Myc, K-Ras and VEGF related to ovarian cancer, to evaluate the mRNA and protein levels of FSHR in the cumulus-oocyte complex (COCs). COCs were cultured for 24 h in the in vitro maturation (IVM) media replenished with 0, 10, 20, 30 and 40 µg/mL FRBI. Contents of c-Myc, K-Ras, VEGF, cAMP and IP3 in IVM media were detected with ELISA kits, respectively. The results indicated that the levels of FSHR protein and mRNA were determined with Western blotting. C-Myc contents of four FRBI + FSH-treated groups (COM groups) were reduced after IVM of COCs. C-Myc concentrations of COM-3 group was lower than the FSH group (p < .05). K-Ras and IP3 contents of COM-4 were decreased as compared to FSH group (p < .05). Expression levels of FSHR mRNAs and proteins in COM-4 group were smaller than that of FSH group. This study revealed that FRBI treatment could decrease c-Myc and K-Ras levels in the IVM medium fluids, and depress the FSHR levels of COCs. Expression levels of FSHR mRNAs and proteins of COM-4 group were significantly decreased. FRBI exerted its action via the signal pathway of IP3 and cAMP.

Association of FSHR missense mutations with female infertility, in silico investigation of their molecular significance and exploration of possible treatments using virtual screening and molecular dynamics.

This study investigated the association of A419T (rs121909661) and T449I (rs28928870) with infertility among Iranian women and possible treatments by agonizing the mutated receptor. 151 women were genotyped at A419T and T449I sites. Homology modeling, pharmacophore modeling, virtual screening, docking and molecular dynamics (MD) were performed. A419T and T449I indicated a significant and a weak association with infertility among Iranian women (P = 0.005 and P = 0.03, respectively). Significant differences found among three genotypes of A419T with FSH (P = 0.01) and LH (P < 0.0001). G-allele carriers of A419T had susceptibility to display higher FSH and LH serum levels. In silico results revealed the most potent agonists among 3041 similar compounds and MD supported this finding. Altogether, genotyping of A419T and T449I as potential markers might be helpful in prognosis and treatment of infertility. Also, a new series of potent FSHR agonists were identified for future drug development and treatment of infertility related to FSHR dysfunction.

Effects of gonadotropin-releasing hormone agonist on human chorionic gonadotropin activity in granulosa cells of immature female rats.

Although the expression of gonadotropin-releasing hormone (GnRH) in the ovaries is well established, its physiological role remains unknown. The aim of this study was to determine whether ovarian GnRH mediates the actions of human chorionic gonadotropin (hCG) in the granulosa cells of immature female rats. Follicular growth was induced by administration of pregnant mare serum gonadotropin (PMSG, 15 IU/0.15 ml) on day 25 after birth, and hCG (20 IU/0.2 ml) was administered on day 27 revealing the increase of plasma progesterone level. Primary cultures of granulosa cells were established from large follicles 2 days after PMSG treatment. Progesterone synthesis was augmented by hCG in a dose-dependent manner. Annexin A5 (ANXA5), a biomarker of GnRH, was expressed in the granulosa-luteal cells after hCG treatment, as shown by immunohistochemistry, suggesting that hCG treatment induced GnRH action. The GnRH mRNA level was increased by hCG, and treatment with GnRH agonist (GnRHa) increased ANXA5 mRNA levels in the primary cultures of granulosa cells. Concomitant incubation of GnRH (10-7 M) or GnRHa (fertirelin acetate, 10-8 M) with hCG suppressed progesterone synthesis during a 3 h incubation period. The mRNA expression of luteinizing hormone receptor (LHR) and follicle-stimulating hormone receptor (FSHR) was synergistically stimulated and suppressed by hCG and GnRHa, respectively. GnRHa stimulated p21 expression, and GnRHa and hCG synergistically reduced the mRNA expression levels of p27 and FOXO1. These data suggest that GnRH induced by LH may have a role for the LH-mediated luteinization of granulosa cells. In addition, ANXA5 may be involved in GnRH action. GnRH-ANXA5 would be an important mechanism in cell differentiation.

Whole-cell biopanning with a synthetic phage display library of nanobodies enabled the recovery of follicle-stimulating hormone receptor inhibitors.

Antibodies are essential reagents that are increasingly used in diagnostics and therapy. Their specificity and capacity to recognize their native antigen are critical characteristics for their in vivo application. Follicle-stimulating hormone receptor is a GPCR protein regulating ovarian follicular maturation and spermatogenesis. Recently, its potentiality as a cancer biomarker has been demonstrated but no antibody suitable for in vivo tumor targeting and treatment has been characterized so far. In this paper we describe the first successful attempt to recover recombinant antibodies against the FSHR and that: i) are directly panned from a pre-immune library using whole cells expressing the target receptor at their surface; ii) show inhibitory activity towards the FSH-induced cAMP accumulation; iii) do not share the same epitope with the natural binder FSH; iv) can be produced inexpensively as mono- or bivalent functional molecules in the bacterial cytoplasm. We expect that the proposed biopanning strategy will be profitable to identify useful functional antibodies for further members of the GPCR class.

Evidence for Follicle-stimulating Hormone Receptor as a Functional Trimer.

Follicle-stimulating hormone receptor (FSHR), a G-protein coupled receptor, is an important drug target in the development of novel therapeutics for reproductive indications. The FSHR extracellular domains were observed in the crystal structure as a trimer, which enabled us to propose a novel model for the receptor activation mechanism. The model predicts that FSHR binds Asnα(52)-deglycosylated FSH at a 3-fold higher capacity than fully glycosylated FSH. It also predicts that, upon dissociation of the FSHR trimer into monomers, the binding of glycosylated FSH, but not deglycosylated FSH, would increase 3-fold, and that the dissociated monomers would in turn enhance FSHR binding and signaling activities by 3-fold. This study presents evidence confirming these predictions and provides crystallographic and mutagenesis data supporting the proposed model. The model also provides a mechanistic explanation to the agonist and antagonist activities of thyroid-stimulating hormone receptor autoantibodies. We conclude that FSHR exists as a functional trimer.

Flow cytometric analysis of FSHR, BMRR1B, LHR and apoptosis in granulosa cells and ovulation rate in merino sheep.

The aim of the present study was to determine the direct cause of the mutation-induced, increased ovulation rate in Booroola Merino (BB) sheep. Granulosa cells were removed from antral follicles before ovulation and post-ovulation from BB (n=5) and WT (n=12) Merino ewes. Direct immunofluorescence measurement of mature cell surface receptors using flow cytometry demonstrated a significant up-regulation of FSH receptor (FSHR), transforming growth factor beta type 1, bone morphogenetic protein receptor (BMPR1B), and LH receptor (LHR) in BB sheep. The increased density of FSHR and LHR provide novel evidence of a mechanism for increasing the number of follicles that are recruited during dominant follicle selection. The compounding increase in receptors with increasing follicle size maintained the multiple follicles and reduced the apoptosis, which contributed to a high ovulation rate in BB sheep. In addition, we report a mutation-independent mechanism of down-regulation to reduce receptor density of the leading dominant follicle in sheep. The suppression of receptor density coincides with the cessation of mitogenic growth and steroidogenic differentiation as part of the luteinization of the follicle. The BB mutation-induced attenuation of BMPR1B signaling led to an increased density of the FSHR and LHR and a concurrent reduction in apoptosis to increase the ovulation rate. The role of BMPs in receptor modulation is implicated in the development of multiple ovulations.

Inhibition of follicle-stimulating hormone-induced preovulatory follicles in rats treated with a nonsteroidal negative allosteric modulator of follicle-stimulating hormone receptor.

We previously described a negative allosteric modulator (NAM) of FSHR (ADX61623) that blocked FSH-induced cAMP and progesterone production but did not block estradiol production. That FSHR NAM did not affect FSH-induced preovulatory follicle development as evidenced by the lack of an effect on the number of FSH-dependent oocytes found in the ampullae following ovulation with hCG. A goal is the development of a nonsteroidal contraceptive. Toward this end, a high-throughput screen using human FSHR identified an additional nonsteroidal small molecule (ADX68692). Although ADX68692 behaved like ADX61623 in inhibiting production of cAMP and progesterone, it also inhibited FSH-induced estradiol in an in vitro rat granulosa primary cell culture bioassay. When immature, noncycling female rats were injected subcutaneously or by oral dosing prior to exogenous FSH administration, it was found that ADX68692 decreased the number of oocytes recovered from the ampullae. The estrous cycles of mature female rats were disrupted by administration by oral gavage of 25 mg/kg and 10 mg/kg ADX68692. In the highest dose tested (25 mg/kg), 55% of animals cohabited with mature males had implantation sites compared to 33% in the 10 mg/kg group and 77% in the control group. A surprising finding was that a structural analog ADX68693, while effectively blocking progesterone production with similar efficacy as ADX68692, did not block estrogen production and despite better oral availability did not decrease the number of oocytes found in the ampullae even when used at 100 mg/kg. These data demonstrate that because of biased antagonism of the FSHR, nonsteroidal contraception requires that both arms of the FSHR steroidogenic pathway must be effectively blocked, particularly estrogen biosynthesis. Thus, a corollary to these findings is that it seems reasonable to propose that the estrogen-dependent diseases such as endometriosis may benefit from inhibition of FSH action at the ovary using the FSHR NAM approach.

Follicle-stimulating hormone induced epithelial-mesenchymal transition of epithelial ovarian cancer cells through follicle-stimulating hormone receptor PI3K/Akt-Snail signaling pathway.

PURPOSE: It has previously been shown that follicle-stimulating hormone (FSH) and its receptor contribute to epithelial ovarian cancer (EOC) development. Epithelial-mesenchymal transition (EMT) is the early event of metastasis in cancer. Therefore, the aim of this study was to investigate the roles of FSH and the FSH receptor (FSHR) in EMT of EOC. METHODS: Ovarian cancer cells treated with various doses of FSH were used to investigate the effect of FSH on EMT. Small interfering RNA-mediated FSHR depletion or reexpression of FSHR by acute transfecting pcDNA-hFSHR plasmid was performed to determine the role of FSHR in FSH-induced EMT. Moreover, LY294002, a potent and specific cell-permeable inhibitor of phosphatidylinositol 3-kinases (PI3K), was selected to pretreat ovarian cancer cells to confirm whether PI3K/Akt signaling is involved in this event. RESULTS: In the current study, FSH was found to induce the phenotypes of EMT including migration and invasion in EOC cells. Elevated FSHR levels promoted EMT, migration, and invasion, whereas small interfering RNA-mediated FSHR knockdown inhibited these processes. Moreover, the inhibition of FSH-induced PI3K/Akt signaling pathway attenuated Snail expression and the EMT process. CONCLUSIONS: Collectively, the findings of the current study indicate that FSH induced the EMT of ovarian cancer cells through the FSHR-PI3K/Akt-Snail signaling pathway.

Premature Ovarian Insufficiency After Coronavirus Disease 2019 (COVID-19): Autoimmune Follicle-Stimulating Hormone (FSH) and FSH Receptor Blockade.

BACKGROUND: Since the onset of the coronavirus disease (COVID-19) pandemic, a variety of long-COVID-19 symptoms and autoimmune complications have been recognized. CASES: We report three cases of autoimmune premature poor ovarian response in patients aged 30-37 years after mild to asymptomatic COVID-19 before vaccination, with nucleotide antibody confirmation. Two patients failed to respond to maximum-dose gonadotropins for more than 4 weeks, despite a recent history of response before having COVID-19. After a month of prednisone 30 mg, these two patients had normal follicle-stimulating hormone (FSH) levels, high oocyte yield, and blastocyst formation in successful in vitro fertilization cycles. All three patients have above-average anti-müllerian hormone levels that persisted throughout their clinical ovarian insufficiency. Two patients had elevated FSH levels, perhaps resulting from FSH receptor blockade. One patient, with a history of high response to gonadotropins 75 international units per day and below-normal FSH levels, had no ovarian response to more than a month of gonadotropins (525 international units daily), suggesting autoimmune block of the FSH glycoprotein and possible FSH receptor blockade. CONCLUSION: Auto-antibody production in response to COVID-19 before vaccination may be a rare cause of autoimmune poor ovarian response. Although vaccination is likely protective, further study will be required to evaluate the effect of vaccination and duration of autoimmune FSH or FSH receptor blockade.

Effects of growth differentiation factor-9 and FSH on in vitro development, viability and mRNA expression in bovine preantral follicles.

The present study investigated the role of growth differentiation factor (GDF)-9 and FSH, alone or in combination, on the growth, viability and mRNA expression of FSH receptor, proliferating cell nuclear antigen (PCNA) and proteoglycan-related factors (i.e., hyaluronan synthase (HAS) 1, HAS2, versican, perlecan) in bovine secondary follicles before and after in vitro culture. After 12 days culture, sequential FSH (100 ng mL⁻¹) from Days 0 to 6 and 500 ng mL⁻¹ from Days 7 to 12) increased follicular diameter and resulted in increased antrum formation (P<0.05). Alone, 200 ng mL⁻¹ GDF-9 significantly reduced HAS1 mRNA levels, but increased versican and perlecan mRNA levels in whole follicles, which included the oocyte, theca and granulosa cells. Together, FSH and GDF-9 increased HAS2 and versican (VCAN) mRNA levels, but decreased PCNA mRNA expression, compared with levels in follicles cultured in α-minimum essential medium supplemented with 3.0 mg mL⁻¹ bovine serum albumin, 10 µg mL⁻¹ insulin, 5.5 µg mL⁻¹ transferrin, 5 ng mL⁻¹ selenium, 2 mM glutamine, 2mM hypoxanthine and 50 µg mL⁻¹ ascorbic acid (α-MEM⁺). Comparisons of uncultured (0.2 mm) and α-MEM⁺ cultured follicles revealed that HAS1 mRNA expression was higher, whereas VCAN expression was lower, in cultured follicles (P<0.05). Expression of HAS1, VCAN and perlecan (HSPG2) was higher in cultured than in vivo-grown (0.3 mm) follicles. In conclusion, FSH and/or GDF-9 promote follicular growth and antrum formation. Moreover, GDF-9 stimulates expression of versican and perlecan and interacts positively with FSH to increase HAS2 expression.

Mapping of FSHR agonists and antagonists binding sites to identify potential peptidomimetic modulators.

Owing to the critical role of follicle stimulating hormone receptor (FSHR) signaling in human reproduction, FSHR has been widely explored for development of fertility regulators. Using high-throughput screening approaches, several low molecular weight (LMW) compounds that can modulate FSHR activity have been identified. However, the information about the binding sites of these molecules on FSHR is not known. In the present study, we extracted the structural and functional information of 161 experimentally validated LMW FSHR modulators available in PubMed records. The potential FSHR binding sites for these modulators were identified through molecular docking experiments. The binding sites were further mapped to the agonist or antagonist activity reported for these molecules in literature. MD simulations were performed to evaluate the effect of ligand binding on conformational changes in the receptor, specifically the transmembrane domain. A peptidomimetic library was screened using these binding sites. Six peptidomimetics that interacted with the residues of transmembrane domain and extracellular loops were evaluated for binding activity using in vitro cAMP assay. Two of the six peptidomimetics exhibited positive allosteric modulatory activity and four peptidomimetics exhibited negative allosteric modulatory activity. All six peptidomimetics interacted with Asp521 of hFSHR(TMD). Several of the experimentally known LMW FSHR modulators also participated in H-bond interactions with Asp521, suggesting its important role in FSHR modulatory activity.

Overview of follicle stimulating hormone and its receptors in reproduction and in stem cells and cancer stem cells.

Follicle stimulating hormone (FSH) and its receptor (FSHR) have been reported to be responsible for several physiological functions and cancers. The responsiveness of stem cells and cancer stem cells towards the FSH-FSHR system make the function of FSH and its receptors more interesting in the context of cancer biology. This review is comprised of comprehensive information on FSH-FSHR signaling in normal physiology, gonadal stem cells, cancer cells, and potential options of utilizing FSH-FSHR system as an anti-cancer therapeutic target.

Expression profiles of gonadotropins and their receptors during 17α-methyltestosterone implantation-induced sex change in the orange-spotted grouper (Epinephelus coioides).

It is known that the hypothalamic-pituitary-gonadal axis participates in the sex change of hermaphrodite teleosts, and gonadal steroid hormones mediate this physiological process. The secretion of gonadal steroids is directly regulated by signaling pathways involving gonadotropins (GtHs) and gonadotropin receptors (GtHRs) in teleosts. To gain insight into the involvement of GtH/GtHR systems in the sex change process, cDNAs encoding follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) were firstly isolated from gonads of orange-spotted grouper (Epinephelus coioides), a protogynous hermaphrodite fish. Reverse transcription-PCR (RT-PCR) analysis demonstrated that the expression of the FSHR was confined to the brain, pituitary gland, ovary, and testis, while the LHR was expressed only in the brain, ovary, and testis. Furthermore, the expression profiles of GtH subunits (FSHß and LHß) and their receptors were analyzed in parallel with the serum levels of estradiol-17ß (E(2) ), testosterone (T), and 11-ketotestosterone (11-KT) during 17α-methyltestosterone (MT)-induced sex change. Quantitative real-time PCR determined that the abundances of FSHß and FSHR were significantly inhibited after MT treatment for 2 and 4 weeks, but subsequently returned to the control level after 6 weeks. In contrast, the mRNA levels of LHß and LHR were significantly elevated throughout the sex change process. During MT-induced sex change, serum concentrations of E(2) remained constant while T and 11-KT levels were significantly increased. Taken together, our results suggest that GtH/GtHR systems are involved in MT-induced sex change, and two signaling pathways may have distinct roles in modulating the variations of the corresponding steroid hormones in the orange-spotted grouper.

Endocrine Disruption of the Follicle-Stimulating Hormone Receptor Signaling During the Human Antral Follicle Growth.

An increasing number of pollutants with endocrine disrupting potential are accumulating in the environment, increasing the exposure risk for humans. Several of them are known or suspected to interfere with endocrine signals, impairing reproductive functions. Follicle-stimulating hormone (FSH) is a glycoprotein playing an essential role in supporting antral follicle maturation and may be a target of disrupting chemicals (EDs) likely impacting female fertility. EDs may interfere with FSH-mediated signals at different levels, since they may modulate the mRNA or protein levels of both the hormone and its receptor (FSHR), perturb the functioning of partner membrane molecules, modify intracellular signal transduction pathways and gene expression. In vitro studies and animal models provided results helpful to understand ED modes of action and suggest that they could effectively play a role as molecules interfering with the female reproductive system. However, most of these data are potentially subjected to experimental limitations and need to be confirmed by long-term observations in human.

Identification and in vivo validation of a 9-mer peptide derived from FSHß with FSHR antagonist activity.

FSH-FSHR interaction is critical for folliculogenesis, spermatogenesis and progression of several cancers. Therefore, FSHR is an attractive target for fertility regulation and cancer therapeutics. Based on homology and structural analysis of hFSH-FSHR(ECD) complex, a minimal continuous stretch within FSHß seat-belt loop (FSHß (89-97)) was identified to be crucial for FSHR interaction. The ability of FSHß (89-97) peptide to neutralize FSHR activity was evaluated by a panel of in vitro and in vivo experiments. The synthetic peptide significantly inhibited binding of [125I]-FSH to rat Fshr as well as FSH-induced cAMP production. In immature rats, FSHß (89-97) peptide administration reduced FSH-mediated increase in ovarian weight. The peptide inhibited transition of follicles from pre-antral to antral stage and hindered the cell cycle progression of granulosa cells beyond G0/G1 phase. In adult rats, administration of the peptide inhibited estradiol synthesis and significantly perturbed folliculogenesis.

Discovery of small molecule binders of human FSHR(TMD) with novel structural scaffolds by integrating structural bioinformatics and machine learning algorithms.

BACKGROUND: The activation of follicle stimulating hormone receptor (FSHR) by FSH and the consequent downstream signaling activities are crucial for reproductive health. The role of FSHR in tumor progression as well as osteoporosis advancement has also been well established. Currently, steroid preparations of estrogen and progesterone are being used for managing fertility, in spite of the harmful side effects, as there has not been much success in identification of effective FSHR modulators. Structure-based drug design initiatives for identification of potent and specific FSHR modulators have been impeded due to the non-availability of the complete crystal structure of hFSHR complexed with FSH. METHODS: In this study, we have modeled the 3D structure of transmembrane domain (TMD) of hFSHR and identified molecules that demonstrate good binding affinity by virtual screening of drug-like library of compounds. The 3D structural and pharmacophoric features of the binders and non-binders obtained from virtual screening were further used to develop Support Vector Machine based classifier for TMD binding. Based on the observations from docking and SVM classification, a small molecule was identified for extensive MD simulations and in vitro assays for FSHR modulatory activity. RESULTS: The molecule selected based on docking score and SVM prediction was found to inhibit FSH-induced cAMP activity by 80% at 300 µM concentration. CONCLUSION: The study proposes 1,3-diphenyl-1H-pyrazole-5-carboxylate as a promising scaffold for the design of new and potent FSHR allosteric inhibitors.

FSH receptor binding inhibitor up-regulates ARID1A and PTEN genes associated with ovarian cancers in mice.

Experiments were conducted to determine if the follicle-stimulating hormone (FSH) receptor binding inhibitor (FRBI) impacts the expression levels of AT-rich interactive domain-containing protein 1A (ARID1A) and phosphatase and tensin homolog (PTEN) in ovaries and blood, as well as expressions of follicle-stimulating hormone cognate receptor (FSHR) gene and proteins. Mice in FRBI-10, FRBI-20, FRBI-30, and FRBI-40 groups were intramuscularly injected with 10, 20, 30, and 40 mg FRBI/kg, respectively, for five consecutive days. Western blotting and qRT-PCR were utilized to determine expression levels of ARID1A and PTEN proteins and mRNAs. Serum ARID1A and PTEN concentrations of the FRBI-40 group were higher than the control group (CG) and FSH group (P<0.05). FSHR mRNA levels of FRBI-20, FRBI-30, and FRBI-40 groups were lower than that of CG and FSH groups on day 15 (P<0.05 or P<0.01). Expression levels of FSHR proteins of FRBI-30 and FRBI-40 groups were lower than those of CG and FSH groups (P<0.05). Levels of ARID1A and PTEN proteins of the FRBI-30 group were greater than CG on days 20 and 30 (P<0.05). FRBI doses had significant positive correlations to levels of ARID1A and PTEN proteins. Additionally, ARID1A and PTEN had negative correlations to FSHR mRNAs and proteins. A high dose of FRBI could promote the expression levels of ARID1A and PTEN proteins in ovarian tissues. FRBI increased serum concentrations of ARID1A and PTEN. However, FRBI depressed expression levels of FSHR mRNAs and proteins in mouse ovaries.

Discovery of BAY-298 and BAY-899: Tetrahydro-1,6-naphthyridine-Based, Potent, and Selective Antagonists of the Luteinizing Hormone Receptor Which Reduce Sex Hormone Levels in Vivo.

The human luteinizing hormone receptor (hLH-R) is a member of the glycoprotein hormone family of G-protein-coupled receptors (GPCRs), activated by luteinizing hormone (hLH) and essentially involved in the regulation of sex hormone production. Thus, hLH-R represents a valid target for the treatment of sex hormone-dependent cancers and diseases (polycystic ovary syndrome, uterine fibroids, endometriosis) as well as contraception. Screening of the Bayer compound library led to the discovery of tetrahydrothienopyridine derivatives as novel, small-molecule (SMOL) hLH-R inhibitors and to the development of BAY-298, the first nanomolar hLH-R antagonist reducing sex hormone levels in vivo. Further optimization of physicochemical, pharmacokinetic, and safety parameters led to the identification of BAY-899 with an improved in vitro profile and proven efficacy in vivo. BAY-298 and BAY-899 serve as valuable tool compounds to study hLH-R signaling in vitro and to interfere with the production of sex hormones in vivo.