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1.
Zoolog Sci ; 38(1): 51-59, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33639718

RESUMO

In vertebrates, gonadotropin-releasing hormone (GnRH) regulates gonadal maturation by stimulating the synthesis and release of pituitary gonadotropins. GnRH has also been identified in invertebrates. Crustacea consists of several classes including Cephalocarida, Remipedia, Branchiopoda (e.g., tadpole shrimp), Hexanauplia (e.g., barnacle) and Malacostraca (e.g., shrimp, crab). In the malacostracan crustaceans, the presence of GnRH has been detected in several species, mainly by immunohistochemistry. In the present study, we examined whether a GnRH-like peptide exists in the brain and/or nerve ganglion of three classes of crustaceans, the tadpole shrimp Triops longicaudatus (Branchiopoda), the barnacle Balanus crenatus (Hexanauplia), and the hermit crab Pagurus filholi (Malacostraca), by immunohistochemistry using a rabbit polyclonal antibody raised against chicken GnRH-II (GnRH2). This antibody was found to recognize the giant freshwater prawn Macrobrachium rosenbergii GnRH (MroGnRH). In the tadpole shrimp, GnRH-like-immunoreactive (ir) cell bodies were located in the circumesophageal connective of the deuterocerebrum, and GnRH-like-ir fibers were detected also in the ventral nerve cord. In the barnacle, GnRH-like-ir cell bodies and fibers were located in the supraesophageal ganglion (brain), the subesophageal ganglion, and the circumesophageal connective. In the hermit crab, GnRH-like-ir cell bodies were detected in the anterior-most part of the supraesophageal ganglion and the subesophageal ganglion. GnRH-like-ir fibers were observed also in the thoracic ganglion and the eyestalk. These results suggest that a GnRH-like peptide exists widely in crustacean species.


Assuntos
Crustáceos/anatomia & histologia , Crustáceos/metabolismo , Gânglios/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Animais , Imuno-Histoquímica , Peptídeos/análise
2.
Life Sci ; 271: 119179, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33577849

RESUMO

BACKGROUND: Male infertility and reproductive dysfunctions have become major global health problems. Although several causative factors have been attributed to this challenge, of importance are alterations in maternal-foetal environment, diet-induced transcriptional changes and dysregulation in chemical signaling via hypothalamic-gonadal axis. AIM: The present study investigated the impact of maternal high-fat diet (HFD) consumption and the putative role of Quercetin-3-O-rutinoside on reproductive functions of male offspring rats at critical developmental stages with a quest to unravel the underpinned molecular changes. MATERIALS AND METHODS: Fifty-six pregnant rats (previously fed normal diet ND) or 45% HFD) were maintained on supplemented chow (150 mg/kg QR) - ND/QR, HFD/QR throughout gestation. Subsequently, dams (n = 7) and offspring (n = 6) were sacrificed at post-natal day (PND) 21, 28 and 35, respectively, and the blood, placenta, hypothalamus (HT), and testicular samples were processed for molecular analysis of Gonadotropin-releasing hormone (GnRH), Luteinizing hormone (LH), testosterone, chemerin, chemokine-like receptor 1 (CMKLR1), tumour necrosis factor α (TNF-α), interleukin 1ß (IL-1ß) and nuclear factor kappa B (NF-κB). KEY FINDINGS: We observed a significant decrease in GnRH level in the HFD group at PND21 and PND28 in male offspring and treatment with QR significantly reduced GnRH. There was a significant reduction in LH levels in the HFD group at PND 21 in the male offspring accompanied by a significant decrease in testosterone level at PND 28 and PND35 which appears to be age dependent. In the HT, Chemerin and CMKLR1 was significantly upregulated in the HFD group at PND 21 and PND 35 respectively while CMKLR1 was significantly downregulated in the HFD group of the placenta and testis at PND 21. TNF-α, IL-1ß and NF-κB were also expressed in the placenta, HT and testis at PND 21. SIGNIFICANCE: Male fertility is affected by maternal HFD consumption while chemerin, CMKLR1 and TNF-α, may play a significant role in male steroidogenesis. Treatment with QR had little or no ameliorative effect on HFD induced alterations in male reproductive functions.


Assuntos
Dieta Hiperlipídica/efeitos adversos , Glucosídeos/farmacologia , Fenômenos Fisiológicos da Nutrição Materna/fisiologia , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Quercetina/análogos & derivados , Reprodução/fisiologia , Testículo/metabolismo , Animais , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Masculino , Fenômenos Fisiológicos da Nutrição Materna/efeitos dos fármacos , Gravidez , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Quercetina/farmacologia , Ratos , Ratos Sprague-Dawley , Reprodução/efeitos dos fármacos , Testículo/efeitos dos fármacos , Testosterona/metabolismo
3.
Proc Natl Acad Sci U S A ; 118(1)2021 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-33443156

RESUMO

Fertility relies upon pulsatile release of gonadotropin-releasing hormone (GnRH) that drives pulsatile luteinizing hormone secretion. Kisspeptin (KP) neurons in the arcuate nucleus are at the center of the GnRH pulse generation and the steroid feedback control of GnRH secretion. However, KP evokes a long-lasting response in GnRH neurons that is hard to reconcile with periodic GnRH activity required to drive GnRH pulses. Using calcium imaging, we show that 1) the tetrodotoxin-insensitive calcium response evoked by KP relies upon the ongoing activity of canonical transient receptor potential channels maintaining voltage-gated calcium channels in an activated state, 2) the duration of the calcium response is determined by the rate of resynthesis of phosphatidylinositol 4,5-bisphosphate (PIP2), and 3) nitric oxide terminates the calcium response by facilitating the resynthesis of PIP2 via the canonical pathway guanylyl cyclase/3',5'-cyclic guanosine monophosphate/protein kinase G. In addition, our data indicate that exposure to nitric oxide after KP facilitates the calcium response to a subsequent KP application. This effect was replicated using electrophysiology on GnRH neurons in acute brain slices. The interplay between KP and nitric oxide signaling provides a mechanism for modulation of the refractory period of GnRH neurons after KP exposure and places nitric oxide as an important component for tonic GnRH neuronal pulses.


Assuntos
Sinalização do Cálcio/fisiologia , Hormônio Liberador de Gonadotropina/metabolismo , Neurônios/metabolismo , Animais , Núcleo Arqueado do Hipotálamo/metabolismo , Cálcio/metabolismo , Canais de Cálcio/metabolismo , Feminino , Hipotálamo/metabolismo , Kisspeptinas/metabolismo , Hormônio Luteinizante/metabolismo , Masculino , Camundongos , Óxido Nítrico/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatidilinositol 4,5-Difosfato/fisiologia , Cultura Primária de Células/métodos
4.
Life Sci ; 270: 119063, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33460664

RESUMO

Gonadotropin-inhibiting hormone (GnIH) inhibits the synthesis and release of gonadotropin by binding to its receptor. GnIH is involved in animal reproductive regulation, especially ovary function. It can regulate the proliferation, apoptosis and hormone secretion of follicular cells. However, the role and molecular mechanism of GnIH in bovine granulosa cell (bGC) apoptosis is unclear. Here, the effects of GnIH on proliferation, apoptosis, and mitochondrial function of bGCs were detected. A 10-6 mol/mL concentration of GnIH inhibited bGC proliferation, promoted GC apoptosis, and damaged mitochondrial function. Additionally, GnIH significantly decreased the phosphorylation level of p38 (P < 0.01). To explore the role of the p38 signaling pathway in the process of GnIH-induced apoptosis in bGCs, an activator of p38 (U46619) was used to pretreat bGCs. U46619 pretreatment significantly alleviated GnIH damage to bGCs, including proliferation, apoptosis, and mitochondrial function. In conclusion, these results demonstrated that GnIH inhibited proliferation and promoted apoptosis of bGCs via the p38 signaling pathway.


Assuntos
Glicoproteínas/metabolismo , Células da Granulosa/metabolismo , Neuropeptídeos/metabolismo , Animais , Apoptose/efeitos dos fármacos , Bovinos , China , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Gonadotropinas/metabolismo , Células da Granulosa/patologia , Hormônios Hipotalâmicos/metabolismo , Ovário/metabolismo , Transdução de Sinais/efeitos dos fármacos
5.
Ecotoxicol Environ Saf ; 208: 111748, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396074

RESUMO

Microcystin-leucine arginine (MC-LR) is a kind of toxin produced by cyanobacterial, resulting in decrease of testosterone levels in serum and leading to impaired spermatogenesis. Gonadotropin-releasing hormone (GnRH) neurons play crucial roles in the regulation of testosterone release. Meanwhile, it has been demonstrated that MC-LR is capable of entering the GnRH neurons and inducing apoptosis. Nevertheless, the molecular mechanism of MC-LR induced apoptosis of GnRH neurons remains elusive. In present study, we found that MC-LR inhibited the cell viability of GT1-7 cells. In addition, we discovered apoptosis of GnRH neurons and GT1-7 cells treated with MC-LR. And increased intracellular ROS production and the release of intracellular Ca2+ were all observed following exposure to MC-LR. Furthermore, we also found the endoplasmic reticulum stress (ERs) and autophagy were activated by MC-LR. Additionally, pretreatment of the ERs inhibitor (4-Phenyl butyric acid) reduced the apoptotic rate of GT1-7 cells comparing with MC-LR exposure alone. Comparing with MC-LR treatment alone, apoptotic cell death was increased by pretreatment of GT1-7 cells with an autophagy inhibitor (3-methyladenine). Together, our data implicated that the treatment of MC-LR induced the apoptosis of GnRH neurons by activating the ERs resulting in a decrease of serum testosterone level in mice. Autophagy is a protective cellular process which was activated by ER stress and thus protected cells from apoptosis upon MC-LR exposure.


Assuntos
Estresse do Retículo Endoplasmático , Microcistinas/toxicidade , Testosterona/sangue , Animais , Apoptose , Arginina/metabolismo , Bioensaio , Sobrevivência Celular , Cianobactérias/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Leucina/metabolismo , Masculino , Toxinas Marinhas/metabolismo , Camundongos , Microcistinas/metabolismo , Neurônios/metabolismo , Testosterona/metabolismo
7.
Int J Mol Sci ; 21(24)2020 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-33327545

RESUMO

Pituitary Gonadotropin-Releasing Hormone receptors (GnRH-R) mediate the activity of the hypothalamic decapeptide GnRH, thus playing a key role in the regulation of the reproductive axis. Early-stage prostate cancer (PCa) is dependent on serum androgen levels, and androgen-deprivation therapy (ADT), based on GnRH agonists and antagonists, represents the standard therapeutic approach for PCa patients. Unfortunately, the tumor often progresses towards the more aggressive castration-resistant prostate cancer (CRPC) stage. GnRH receptors are also expressed in CRPC tissues, where their binding to both GnRH agonists and antagonists is associated with significant antiproliferative/proapoptotic, antimetastatic and antiangiogenic effects, mediated by the Gαi/cAMP signaling cascade. GnRH agonists and antagonists are now considered as an effective therapeutic strategy for CRPC patients with many clinical trials demonstrating that the combined use of these drugs with standard therapies (i.e., docetaxel, enzalutamide, abiraterone) significantly improves disease-free survival. In this context, GnRH-based bioconjugates (cytotoxic drugs covalently linked to a GnRH-based decapeptide) have been recently developed. The rationale of this treatment is that the GnRH peptide selectively binds to its receptors, delivering the cytotoxic drug to CRPC cells while sparing nontumor cells. Some of these compounds have already entered clinical trials.


Assuntos
Neoplasias de Próstata Resistentes à Castração/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo , Receptores LHRH/metabolismo , Androstenos/uso terapêutico , Animais , Docetaxel/uso terapêutico , Hormônio Liberador de Gonadotropina/metabolismo , Humanos , Masculino , Feniltioidantoína/análogos & derivados , Feniltioidantoína/uso terapêutico , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos
8.
Nat Commun ; 11(1): 5287, 2020 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-33082324

RESUMO

Gonadotrophin-releasing hormone (GnRH), also known as luteinizing hormone-releasing hormone, is the main regulator of the reproductive system, acting on gonadotropic cells by binding to the GnRH1 receptor (GnRH1R). The GnRH-GnRH1R system is a promising therapeutic target for maintaining reproductive function; to date, a number of ligands targeting GnRH1R for disease treatment are available on the market. Here, we report the crystal structure of GnRH1R bound to the small-molecule drug elagolix at 2.8 Å resolution. The structure reveals an interesting N-terminus that could co-occupy the enlarged orthosteric binding site together with elagolix. The unusual ligand binding mode was further investigated by structural analyses, functional assays and molecular docking studies. On the other hand, because of the unique characteristic of lacking a cytoplasmic C-terminal helix, GnRH1R exhibits different microswitch structural features from other class A GPCRs. In summary, this study provides insight into the ligand binding mode of GnRH1R and offers an atomic framework for rational drug design.


Assuntos
Receptores LHRH/química , Receptores LHRH/metabolismo , Sítios de Ligação , Cristalização , Hormônio Liberador de Gonadotropina/química , Hormônio Liberador de Gonadotropina/metabolismo , Humanos , Hidrocarbonetos Fluorados/química , Hidrocarbonetos Fluorados/metabolismo , Ligantes , Simulação de Acoplamento Molecular , Conformação Proteica em alfa-Hélice , Pirimidinas/química , Pirimidinas/metabolismo , Receptores LHRH/genética
9.
Ecotoxicol Environ Saf ; 201: 110712, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32502905

RESUMO

Exposure to manganese (Mn) can cause male reproductive damage and lead to abnormal secretion of sex hormones. Gonadotropin-releasing hormone (GnRH) plays an important role in the neuromodulation of vertebrate reproduction. Astrocytes can indirectly regulate the secretion of GnRH by binding paracrine prostaglandin E2 (PGE2) specifically to the EP1 and EP2 receptors on GnRH neurons. Prior studies assessed the abnormal secretion of GnRH caused by Mn exposure, but the specific mechanism has not been reported in detail. This study investigated the effects of Mn exposure on the reproductive system of male mice to clarify the role of PGE2 in the abnormal secretion of GnRH in the hypothalamus caused by exposure to Mn. Our data demonstrate that antagonizing the EP1 and EP2 receptors of PGE2 can restore abnormal levels of GnRH caused by Mn exposure. Mn exposure causes reduced sperm count and sperm shape deformities. These findings suggest that EP1 and EP2, the receptors of PGE2, may be the key to abnormal GnRH secretion caused by Mn exposure. Antagonizing the PGE2 receptors may reduce reproductive damage caused by Mn exposure.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/efeitos dos fármacos , Manganês/toxicidade , Receptores de Prostaglandina E Subtipo EP1/metabolismo , Receptores de Prostaglandina E Subtipo EP2/metabolismo , Reprodução/efeitos dos fármacos , Animais , Hipotálamo/metabolismo , Masculino , Manganês/metabolismo , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Receptores de Prostaglandina E Subtipo EP1/antagonistas & inibidores , Receptores de Prostaglandina E Subtipo EP2/antagonistas & inibidores
10.
Biochim Biophys Acta Rev Cancer ; 1874(1): 188383, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32535158

RESUMO

Androgen deprivation therapy (ADT) is the primary systemic therapy for treating locally advanced or metastatic prostate cancer (PCa). Despite its positive effect on PCa patient survival, ADT causes various adverse effects, including increased cardiovascular risk factors and cardiotoxicity. Lifespans extension, early use of ADT, and second-line treatment with next-generation androgen receptor pathway inhibitors would further extend the duration of ADT and possibly increase the risk of ADT-induced cardiotoxicity. Meanwhile, information on the molecular mechanisms underlying ADT-induced cardiotoxicity and measures to prevent it is limited, mainly due to the lack of specifically designed preclinical studies and clinical trials. This review article compiles up-to-date evidence obtained from observational studies and clinical trials, in order to gain new insights for deciphering the association between ADT use and cardiotoxicity. In addition, potential cardioprotective strategies involving GnRH receptors and second messenger cGMP are discussed.


Assuntos
Antagonistas de Androgênios/efeitos adversos , Antineoplásicos Hormonais/efeitos adversos , Doenças Cardiovasculares/epidemiologia , Neoplasias da Próstata/tratamento farmacológico , Antagonistas de Androgênios/administração & dosagem , Androgênios/metabolismo , Antineoplásicos Hormonais/administração & dosagem , Cardiotoxicidade/epidemiologia , Cardiotoxicidade/etiologia , Cardiotoxicidade/fisiopatologia , Cardiotoxicidade/prevenção & controle , Doenças Cardiovasculares/induzido quimicamente , Doenças Cardiovasculares/fisiopatologia , Doenças Cardiovasculares/prevenção & controle , Ensaios Clínicos como Assunto , GMP Cíclico/metabolismo , Hormônio Liberador de Gonadotropina/agonistas , Hormônio Liberador de Gonadotropina/antagonistas & inibidores , Hormônio Liberador de Gonadotropina/metabolismo , Humanos , Longevidade/fisiologia , Masculino , Estudos Observacionais como Assunto , Inibidores da Fosfodiesterase 5/farmacologia , Inibidores da Fosfodiesterase 5/uso terapêutico , Receptores LHRH/agonistas , Receptores LHRH/antagonistas & inibidores , Receptores LHRH/metabolismo , Fatores de Risco , Transdução de Sinais/efeitos dos fármacos , Fatores de Tempo , Resultado do Tratamento
11.
DNA Cell Biol ; 39(6): 1012-1022, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32352843

RESUMO

Kisspeptin has been identified as a key regulatory protein in the release of gonadotropin-releasing hormone (GnRH), which subsequently increases gonadotropin secretion during puberty to establish reproductive function and regulate the hypothalamic-pituitary-gonadal axis. The effects of variants in the KISS1, KISS1R, and GNRHR genes and their possible association with assisted reproduction outcomes remain to be elucidated. In this study, we used next-generation sequencing to investigate the associations of the genetic diversity at the candidate loci for KISS1, KISS1R, and GNRHR with the hormonal profiles and reproductive outcomes in 86 women who underwent in vitro fertilization treatments. Variants in the KISS1 and KISS1R genes were associated with luteinizing hormone (rs35431622:T>C), anti-Mullerian hormone (rs71745629delT), follicle-stimulating hormone (rs73507529:C>A), and estradiol (rs73507527:G>A, rs350130:A>G, and rs73507529:C>A) levels, as well as with reproductive outcomes such as the number of oocytes retrieved (s35431622:T>C), metaphasis II oocytes (rs35431622:T>C), and embryos (rs1132506:G>C). Additionally, variants in the GNRHR UTR3' (rs1038426:C>A, rs12508464:A>C, rs13150734:C>A, rs17635850:A>G, rs35683646:G>A, rs35610027:C>G, rs35845954:T>C, rs17635749:C>T, and rs7666201:C>T) were associated with low prolactin levels. A conjoint analysis of clinical, hormonal, and genetic variables using a generalized linear model identified two variants of the KISS1 gene (rs71745629delT and rs1132506:G>C) that were significantly associated with hormonal variations and reproductive outcomes. The findings suggest that variants in KISS1, KISS1R, and GNRHR genes can modulate hormone levels and reproductive outcomes.


Assuntos
Variação Genética , Hormônio Liberador de Gonadotropina/metabolismo , Kisspeptinas/genética , Receptores de Kisspeptina-1/genética , Receptores LHRH/genética , Reprodução/genética , Adulto , Feminino , Loci Gênicos/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Infertilidade/genética
12.
Am J Physiol Endocrinol Metab ; 319(1): E81-E90, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32396496

RESUMO

We have previously shown that systemic injection of erythropoietin-producing hepatocellular receptor A7 (EPHA7)-Fc raises serum luteinizing hormone (LH) levels before ovulation in female rats, indicating the induction of EPHA7 in ovulation. In this study, we aimed to identify the mechanism and hypothalamus-pituitary-ovary (HPO) axis level underlying the promotion of LH secretion by EPHA7. Using an ovariectomized (OVX) rat model, in conjunction with low-dose 17ß-estradiol (E2) treatment, we investigated the association between EPHA7-ephrin (EFN)A5 signaling and E2 negative feedback. Various rat models (OVX, E2-treated OVX, and abarelix treated) were injected with the recombinant EPHA7-Fc protein through the caudal vein to investigate the molecular mechanism underlying the promotion of LH secretion by EPHA7. Efna5 was observed strongly expressed in the arcuate nucleus of the female rat by using RNAscope in situ hybridization. Our results indicated that E2, combined with estrogen receptor (ER)α, but not ERß, inhibited Efna5 and gonadotropin-releasing hormone 1 (Gnrh1) expressions in the hypothalamus. In addition, the systemic administration of EPHA7-Fc restrained the inhibition of Efna5 and Gnrh1 by E2, resulting in increased Efna5 and Gnrh1 expressions in the hypothalamus as well as increased serum LH levels. Collectively, our findings demonstrated the involvement of EPHA7-EFNA5 signaling in the regulation of LH and the E2 negative feedback pathway in the hypothalamus, highlighting the functional role of EPHA7 in female reproduction.


Assuntos
Efrina-A5/metabolismo , Receptor alfa de Estrogênio/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Hormônio Luteinizante/metabolismo , Precursores de Proteínas/metabolismo , Animais , Núcleo Arqueado do Hipotálamo/efeitos dos fármacos , Núcleo Arqueado do Hipotálamo/metabolismo , Efrina-A5/efeitos dos fármacos , Efrina-A5/genética , Estradiol/farmacologia , Receptor beta de Estrogênio/metabolismo , Estrogênios/farmacologia , Retroalimentação Fisiológica/efeitos dos fármacos , Retroalimentação Fisiológica/fisiologia , Feminino , Hormônio Liberador de Gonadotropina/efeitos dos fármacos , Antagonistas de Hormônios/farmacologia , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/metabolismo , Hipotálamo/efeitos dos fármacos , Hormônio Luteinizante/efeitos dos fármacos , Oligopeptídeos/farmacologia , Ovariectomia , Ovário/efeitos dos fármacos , Ovário/metabolismo , Precursores de Proteínas/efeitos dos fármacos , Ratos , Receptor EphA7/genética , Receptor EphA7/metabolismo , Receptor EphA7/farmacologia , Proteínas Recombinantes
13.
Proc Natl Acad Sci U S A ; 117(23): 12772-12783, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32467166

RESUMO

The luteinizing hormone surge is essential for fertility as it triggers ovulation in females and sperm release in males. We previously reported that secretoneurin-a, a neuropeptide derived from the processing of secretogranin-2a (Scg2a), stimulates luteinizing hormone release, suggesting a role in reproduction. Here we provide evidence that mutation of the scg2a and scg2b genes using TALENs in zebrafish reduces sexual behavior, ovulation, oviposition, and fertility. Large-scale spawning within-line crossings (n = 82 to 101) were conducted. Wild-type (WT) males paired with WT females successfully spawned in 62% of the breeding trials. Spawning success was reduced to 37% (P = 0.006), 44% (P = 0.0169), and 6% (P < 0.0001) for scg2a -/- , scg2b -/- , and scg2a -/- ;scg2b -/- mutants, respectively. Comprehensive video analysis indicates that scg2a -/- ;scg2b -/- mutation reduces all male courtship behaviors. Spawning success was 47% in saline-injected WT controls compared to 11% in saline-injected scg2a -/- ;scg2b -/- double mutants. For these mutants, spawning success increased 3-fold following a single intraperitoneal (i.p.) injection of synthetic secretoneurin-a (P = 0.0403) and increased 3.5-fold with injection of human chorionic gonadotropin (hCG). Embryonic survival at 24 h remained on average lower in scg2a -/- ;scg2b -/- fish compared to WT injected with secretoneurin-a (P < 0.001). Significant reductions in the expression of gonadotropin-releasing hormone 3 in the hypothalamus, and luteinizing hormone beta and glycoprotein alpha subunits in the pituitary provide evidence for disrupted hypothalamo-pituitary function in scg2a and scg2b mutant fish. Our results indicate that secretogranin-2 is required for optimal reproductive function and support the hypothesis that secretoneurin is a reproductive hormone.


Assuntos
Fertilidade , Preferência de Acasalamento Animal , Mutação , Secretogranina II/genética , Proteínas de Peixe-Zebra/genética , Animais , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Hormônio Luteinizante/metabolismo , Masculino , Neuropeptídeos/metabolismo , Oviposição , Ovulação , Hipófise/metabolismo , Secretogranina II/metabolismo , Peixe-Zebra , Proteínas de Peixe-Zebra/metabolismo
14.
Am J Physiol Endocrinol Metab ; 318(6): E901-E919, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32286880

RESUMO

Lack of GABAB receptors in GABAB1 knockout mice decreases neonatal ARC kisspeptin 1 (Kiss1) expression in the arcuate nucleus of the hypothalamus (ARC) in females, which show impaired reproduction as adults. Our aim was to selectively impair GABAB signaling during a short postnatal period to evaluate its impact on the reproductive system. Neonatal male and female mice were injected with the GABAB antagonist CGP 55845 (CGP, 1 mg/kg body wt sc) or saline from postnatal day 2 (PND2) to PND6, three times per day (8 AM, 1 PM, and 6 PM). One group was killed on PND6 for collection of blood samples (hormones by radioimmunoassay), brains for gene expression in the anteroventral periventricular nucleus-periventricular nucleus continuum (AVPV/PeN), and ARC micropunches [quantitative PCR (qPCR)] and gonads for qPCR, hormone contents, and histology. A second group of mice was injected with CGP (1 mg/kg body wt sc) or saline from PND2 to PND6, three times per day (8 AM, 1 PM, and 6 PM), and left to grow to adulthood. We measured body weight during development and parameters of sexual differentiation, puberty onset, and estrous cycles. Adult mice were killed, and trunk blood (hormones), brains for qPCR, and gonads for qPCR and hormone contents were obtained. Our most important findings on PND6 include the CGP-induced decrease in ARC Kiss1 and increase in neurokinin B (Tac2) in both sexes; the decrease in AVPV/PeN tyrosine hydroxylase (Th) only in females; the increase in gonad estradiol content in both sexes; and the increase in primordial follicles and decrease in primary and secondary follicles. Neonatally CGP-treated adults showed decreased ARC Kiss1 and ARC gonadotropin-releasing hormone (Gnrh1) and increased ARC glutamic acid decarboxylase 67 (Gad1) only in males; increased ARC GABAB receptor subunit 1 (Gabbr1) in both sexes; and decreased AVPV/PeN Th only in females. We demonstrate that ARC Kiss1 expression is chronically downregulated in males and that the normal sex difference in AVPV/PeN Th expression is abolished. In conclusion, neonatal GABAergic input through GABAB receptors shapes gene expression of factors critical to reproduction.


Assuntos
Núcleo Arqueado do Hipotálamo/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Hipotálamo Anterior/metabolismo , Receptores de GABA-B/metabolismo , Animais , Animais Recém-Nascidos , Núcleo Arqueado do Hipotálamo/efeitos dos fármacos , Estradiol/metabolismo , Feminino , Hormônio Foliculoestimulante/metabolismo , Antagonistas de Receptores de GABA-B/farmacologia , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Glutamato Descarboxilase/genética , Glutamato Descarboxilase/metabolismo , Hormônio Liberador de Gonadotropina/genética , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo Anterior/efeitos dos fármacos , Kisspeptinas/genética , Kisspeptinas/metabolismo , Hormônio Luteinizante/metabolismo , Masculino , Camundongos , Ovário/efeitos dos fármacos , Ovário/metabolismo , Ácidos Fosfínicos/farmacologia , Propanolaminas/farmacologia , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Puberdade/efeitos dos fármacos , Puberdade/genética , Receptores Estrogênicos/genética , Receptores Estrogênicos/metabolismo , Receptores de GABA-B/genética , Receptores de Progesterona/genética , Receptores de Progesterona/metabolismo , Reprodução/efeitos dos fármacos , Reprodução/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Diferenciação Sexual/efeitos dos fármacos , Diferenciação Sexual/genética , Taquicininas/genética , Taquicininas/metabolismo , Testículo/efeitos dos fármacos , Testículo/metabolismo , Testosterona/metabolismo , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo
15.
Gen Comp Endocrinol ; 292: 113465, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32184073

RESUMO

Gonadotropin-releasing hormone (GnRH) neurons are master regulators of the reproductive axis in vertebrates. During early mammalian embryogenesis, GnRH1 neurons emerge in the nasal/olfactory placode. These neurons undertake a long-distance migration, moving from the nose to the preoptic area and hypothalamus. While significant advances have been made in understanding the functional importance of the GnRH1 neurons in reproduction, where GnRH1 neurons come from and how are they specified during early development is still under debate. In addition to the GnRH1 gene, most vertebrate species including humans have one or two additional GnRH genes. Compared to the GnRH1 neurons, much less is known about the development and regulation of GnRH2 neuron and GnRH3 neurons. The objective of this article is to review what is currently known about GnRH neuron development. We will survey various cell autonomous and non-autonomous factors implicated in the regulation of GnRH neuron development. Finally, we will discuss emerging tools and new approaches to resolve open questions pertaining to GnRH neuron development.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Neurônios/metabolismo , Vertebrados/metabolismo , Animais , Hormônio Liberador de Gonadotropina/genética , Humanos , Modelos Biológicos , Neurogênese
16.
Gen Comp Endocrinol ; 293: 113469, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32220572

RESUMO

Timing of seasonal reproduction is driven by environmental cues acting on the hypothalamic-pituitary-gonadal (HPG) axis. Groups of individuals, or populations, of the same species can exhibit different phenology despite facing similar environmental cues or living in the same habitat (i.e., seasonal sympatry). The mechanisms giving rise to population-level differences in reproductive timing are not fully understood, particularly for females. We studied the dark-eyed junco, a songbird with migratory and sedentary (i.e., resident) populations that live in overlapping distributions during winter. In early spring, residents initiate breeding and associated behaviors, including territory establishment and formation of pair bonds, while migrants prepare to depart for their breeding grounds. We tested whether migrant and resident hormonal response to upstream hormonal stimulation differed during this time period. We collected blood from free-living females in early spring, and challenged them with repeated gonadotropin-releasing hormone (GnRH) injections to measure testosterone (T) response. We predicted that if migrants are less sensitive to upstream stimulation than residents, then they would exhibit lower response to the repeated GnRH challenges in migrants. We found that migrant and resident females both responded to an initial challenge by elevating T, but residents responded more robustly, indicating that the ovary plays a role in population-level differences in reproductive timing. We also found that migrants and residents attenuated their response to repeated challenges, and did not differ from one another in final T levels. We speculate that the explanation for the generally reduced T response after repeated GnRH injections need not be the same for migrants and residents, but possible explanations include suppression of upstream stimulation owing to negative feedback after the initial injection oraromatization of T to estradiol between sampling time points. We suggest that future studies experimentally explore how the ovarian response to upstream stimulation changes during the transition to reproduction.


Assuntos
Migração Animal/fisiologia , Gônadas/fisiologia , Estações do Ano , Aves Canoras/fisiologia , Simpatria , Animais , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Masculino , Aves Canoras/anatomia & histologia , Aves Canoras/sangue , Testosterona/sangue
17.
Gene ; 738: 144488, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32087275

RESUMO

Kisspeptin, encoded by the Kiss1 gene, and its receptor GPR54 have a central regulatory role in the male reproduction. However, their functions in peripheral tissues, such as testes, remain unclear. This study investigated the local expressions and function of Kiss1/GPR54 in goats' testes. The mRNA expression of Kiss1/GPR54 in pubertal goat Leydig cells was detected through reverse transcriptase PCR (RT-PCR), and its protein expression in Leydig cells or the testis was examined by immunohistochemistry and Western blot analysis. Isolated and cultured Leydig cells were treated with different concentration of kisspeptin (0, 1, 10 and 100 µM) and kisspeptin antagonist for 4, 24 or 72 h. The direct effect of kisspeptin on testosterone secretion and Kiss1/GPR54 mRNA expression was evaluated by ELISA and RT-PCR. Kiss1/GPR54 mRNA and protein were expressed in Leydig cells and spermatids, and GPR54 were expressed in Sertoli cells. Kisspeptin treatment significantly stimulated testosterone secretion in Leydig cells, with the highest levels found under 24 h of treatment with 10 µM kisspeptin. Treatment with kisspeptin + kisspeptin antagonist significantly reduced the kisspeptin-stimulated testosterone secretion in Leydig cells. Kisspeptin treatment significantly enhanced the expression of Kiss1/GPR54 mRNA in Leydig cells. These data suggest the local expressions of Kiss1/GPR54 in goats' testes and its autocrine role in Leydig cells, which is helpful in understanding the regulation role of kisspeptin/GPR54 system in other peripheral tissues.


Assuntos
Cabras/genética , Kisspeptinas/genética , Testículo/metabolismo , Animais , China , Células Germinativas/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Células Intersticiais do Testículo/metabolismo , Masculino , RNA Mensageiro/metabolismo , Receptores Acoplados a Proteínas-G/genética , Células de Sertoli/metabolismo
18.
Gen Comp Endocrinol ; 291: 113418, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32027878

RESUMO

Although testosterone (T) is a key regulator in vertebrate development, physiology, and behaviour in both sexes, studies suggest that its regulation may be sex-specific. We measured circulating T levels in Baluchistan gerbils (Gerbillus nanus) in the field and in the lab all year round and found no significant sex differences. However, we observed sex differences in circulating T levels following gonadotropin-releasing hormone (GnRH) challenge and T implants in this non-model species. Whereas only males elevated T following a GnRH challenge, females had higher serum T concentrations following T implant insertion. These differences may be a result of different points of regulation along the hypothalamic-pituitary-gonadal (HPG) axis. Consequently, we examined sex differences in the mRNA expression of the androgen receptor (AR) in multiple brain regions. We identified AR and ß-actin sequences in assembled genomic sequences of members of the Gerbillinae, which were analogous to rat sequences, and designed primers for them. The distribution of the AR in G. nanus brain regions was similar to documented expression profiles in rodents. We found lower AR mRNA levels in females in the striatum. Additionally, G. nanus that experienced housing in mixed-sex pairs had higher adrenal AR expression than G. nanus that were housed alone. Regulation of the gerbil HPG axis may reflect evolutionary sex differences in life-history strategies, with males ready to reproduce when receptive females are available, while the possible reproductive costs associated with female T direct its regulation upstream.


Assuntos
Gerbillinae/sangue , Caracteres Sexuais , Testosterona/sangue , Sequência de Aminoácidos , Animais , Feminino , Regulação da Expressão Gênica , Gerbillinae/genética , Hormônio Liberador de Gonadotropina/metabolismo , Masculino , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Androgênicos/química , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo
19.
Gen Comp Endocrinol ; 291: 113422, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32032603

RESUMO

Fish have been of paramount importance to our understanding of vertebrate comparative neuroendocrinology and the mechanisms underlying the physiology and evolution of gonadotropin-releasing hormones (GnRH) and their genes. This review integrates past and recent knowledge on the Gnrh system in the fish model. Multiple Gnrh isoforms (two or three forms) are present in all teleosts, as well as multiple Gnrh receptors (up to five types), which differ in neuroanatomical localization, pattern of projections, ontogeny and functions. The role of the different Gnrh forms in reproduction seems to also differ in teleost models possessing two versus three Gnrh forms, Gnrh3 being the main hypophysiotropic hormone in the former and Gnrh1 in the latter. Functions of the non-hypothalamic Gnrh isoforms are still unclear, although under suboptimal physiological conditions (e.g. fasting), Gnrh2 may increase in the pituitary to ensure the integrity of reproduction under these conditions. Recent developments in transgenesis and mutagenesis in fish models have permitted the generation of fish lines expressing fluorophores in Gnrh neurons and to elucidate the dynamics of the elaborate innervations of the different neuronal populations, thus enabling a more accurate delineation of their reproductive roles and regulations. Moreover, in combination with neuronal electrophysiology, these lines have clarified the Gnrh mode of actions in modulating Lh and Fsh activities. While loss of function and genome editing studies had the premise to elucidate the exact roles of the multiple Gnrhs in reproduction and other processes, they have instead evoked an ongoing debate about these roles and opened new avenues of research that will no doubt lead to new discoveries regarding the not-yet-fully-understood Gnrh system.


Assuntos
Peixes/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Animais , Encéfalo/metabolismo , Peixes/genética , Peixes/crescimento & desenvolvimento , Genoma , Hormônio Liberador de Gonadotropina/química , Sistemas Neurossecretores/metabolismo , Receptores LHRH/química , Receptores LHRH/metabolismo
20.
J Steroid Biochem Mol Biol ; 200: 105627, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32070756

RESUMO

The South American plains vizcacha, Lagostomus maximus, is the only mammal described so far that shows expression of estrogen receptors (ERs) and progesterone receptors (PRs) in gonadotropin-releasing hormone (GnRH) neurons. This animal therefore constitutes an exceptional model for the study of the effect of steroid hormones on the modulation of the hypothalamic-pituitary-ovarian (HPO) axis. By using both in vivo and ex vivo approaches, we have found that pharmacological doses of progesterone (P4) and estradiol (E2) produced an inhibition in the expression of hypothalamic GnRH, while physiological doses produced a differential effect on the pulsatile release frequency or genomic expression of GnRH. Our ex vivo experiment indicates that a short-term effect of E2 modulates the frequency of GnRH release pattern that would be associated with membrane ERs. On the other hand, our in vivo approach suggests that a long-term effect of E2, acting through the classical nuclear ERs-PRs pathway, would produce the modification of GnRH mRNA expression during the GnRH pre-ovulatory surge. Particularly, P4 induced a rise in GnRH mRNA expression and protein release with a decrease in its release frequency. These results suggest different levels of action of steroid hormones on GnRH modulation. We conclude that the fine action of E2 and P4 constitute the key factor to enable the hypothalamic activity during the pregnancy of this mammal.


Assuntos
Estradiol/farmacologia , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/efeitos dos fármacos , Progesterona/farmacologia , Animais , Estradiol/sangue , Feminino , Hormônio Liberador de Gonadotropina/genética , Sistema Hipotálamo-Hipofisário , Hipotálamo/metabolismo , Hormônio Luteinizante/metabolismo , Ovariectomia , Ovário , Progesterona/sangue , Roedores
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