Excitatory effects of the puberty-initiating peptide kisspeptin and group I metabotropic glutamate receptor agonists differentiate two distinct subpopulations of gonadotropin-releasing hormone neurons.
Ontology highlight
ABSTRACT:
SUBMITTER: Dumalska I
PROVIDER: S-EPMC2597556 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:We examined the role of kisspeptin and its receptor, the G-protein-coupled receptor GPR54, in governing the onset of puberty in the mouse. In the adult male and female mouse, kisspeptin (10-100 nM) evoked a remarkably potent, long-lasting depolarization of >90% of gonadotropin-releasing hormone (GnRH)-green fluorescent protein neurons in situ. In contrast, in juvenile [postnatal day 8 (P8) to P19] and prepubertal (P26-P33) male mice, kisspeptin activated only 27 and 44% of GnRH neurons, respectively. This developmental recruitment of GnRH neurons into a kisspeptin-responsive pool was paralleled by an increase in the ability of centrally administered kisspeptin to evoke luteinizing hormone secretion in vivo. To learn more about the mechanisms through which kisspeptin-GPR54 signaling at the GnRH neuron may change over postnatal development, we performed quantitative in situ hybridization for kisspeptin and GPR54 transcripts. Approximately 90% of GnRH neurons were found to express GPR54 mRNA in both juvenile and adult mice, without a detectable difference in the mRNA content between the age groups. In contrast, the expression of KiSS-1 mRNA increased dramatically across the transition from juvenile to adult life in the anteroventral periventricular nucleus (AVPV; p < 0.001). These results demonstrate that kisspeptin exerts a potent depolarizing effect on the excitability of almost all adult GnRH neurons and that the responsiveness of GnRH neurons to kisspeptin increases over postnatal development. Together, these observations suggest that activation of GnRH neurons by kisspeptin at puberty reflects a dual process involving an increase in kisspeptin input from the AVPV and a post-transcriptional change in GPR54 signaling within the GnRH neuron.
| S-EPMC6725899 | biostudies-literature
Project description:Most central neurons in the mammalian brain possess an appendage called a primary cilium that projects from the soma into the extracellular space. The importance of these organelles is highlighted by the fact that primary cilia dysfunction is associated with numerous neuropathologies, including hyperphagia-induced obesity, hypogonadism, and learning and memory deficits. Neuronal cilia are enriched for signaling molecules, including certain G protein-coupled receptors (GPCRs), suggesting that neuronal cilia sense and respond to neuromodulators in the extracellular space. However, the impact of cilia on signaling to central neurons has never been demonstrated. Here, we show that the kisspeptin receptor (Kiss1r), a GPCR that is activated by kisspeptin to regulate the onset of puberty and adult reproductive function, is enriched in cilia projecting from mouse gonadotropin-releasing hormone (GnRH) neurons. Interestingly, GnRH neurons in adult animals are multiciliated and the percentage of GnRH neurons possessing multiple Kiss1r-positive cilia increases during postnatal development in a progression that correlates with sexual maturation. Remarkably, disruption of cilia selectively on GnRH neurons leads to a significant reduction in kisspeptin-mediated GnRH neuronal activity. To our knowledge, this result is the first demonstration of cilia disruption affecting central neuronal activity and highlights the importance of cilia for proper GPCR signaling.
| S-EPMC4104922 | biostudies-literature
Project description:Kisspeptin and its cognate receptor, GPR54, are critical for reproductive development and for the regulation of gonadotropin-releasing hormone (GnRH) secretion. Although kisspeptin has been found to depolarize GnRH neurons, the underlying ionic mechanism has not been elucidated. Presently, we found that kisspeptin depolarized GnRH neurons in a concentration-dependent manner with a maximum depolarization of 22.6 +/- 0.6 mV and EC(50) of 2.8 +/- 0.2 nM. Under voltage-clamp conditions, kisspeptin induced an inward current of 18.2 +/- 1.6 pA (V(hold) = -60 mV) that reversed near -115 mV in GnRH neurons. The more negative reversal potential than E(K)(+) (-90 mV) was caused by the concurrent inhibition of barium-sensitive, inwardly rectifying (Kir) potassium channels and activation of sodium-dependent, nonselective cationic channels (NSCCs). Indeed, reducing extracellular Na(+) (to 5 mM) essentially eliminated the kisspeptin-induced inward current. The current-voltage relationships of the kisspeptin-activated NSCC currents exhibited double rectification with negative slope conductance below -40 mV in the majority of the cells. Pharmacological examination showed that the kisspeptin-induced inward currents were blocked by TRPC (canonical transient receptor potential) channel blockers 2-APB (2-aminoethyl diphenylborinate), flufenamic acid, SKF96365 (1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride), and Cd(2+), but not by lanthanum (100 microM). Furthermore, single-cell reverse transcription-PCR analysis revealed that TRPC1, TRPC3, TRPC4, TRPC5, TRPC6, and TRPC7 subunits were expressed in GnRH neurons. Therefore, it appears that kisspeptin depolarizes GnRH neurons through activating TRPC-like channels and, to a lesser extent, inhibition of Kir channels. These actions of kisspeptin contribute to the pronounced excitation of GnRH neurons that is critical for mammalian reproduction.
| S-EPMC6670958 | biostudies-literature
Project description:Early or late pubertal onset affects up to 5% of adolescents and is associated with adverse health and psychosocial outcomes. Self-limited delayed puberty (DP) segregates predominantly in an autosomal dominant pattern, but the underlying genetic background is unknown. Using exome and candidate gene sequencing, we have identified rare mutations in IGSF10 in 6 unrelated families, which resulted in intracellular retention with failure in the secretion of mutant proteins. IGSF10 mRNA was strongly expressed in embryonic nasal mesenchyme, during gonadotropin-releasing hormone (GnRH) neuronal migration to the hypothalamus. IGSF10 knockdown caused a reduced migration of immature GnRH neurons in vitro, and perturbed migration and extension of GnRH neurons in a gnrh3:EGFP zebrafish model. Additionally, loss-of-function mutations in IGSF10 were identified in hypothalamic amenorrhea patients. Our evidence strongly suggests that mutations in IGSF10 cause DP in humans, and points to a common genetic basis for conditions of functional hypogonadotropic hypogonadism (HH). While dysregulation of GnRH neuronal migration is known to cause permanent HH, this is the first time that this has been demonstrated as a causal mechanism in DP‡.
| S-EPMC4888853 | biostudies-literature
Project description:Pulsatile release of hypothalamic gonadotropin-releasing hormone (GnRH) is essential for pituitary gonadotrope function. Although the importance of pulsatile GnRH secretion has been recognized for several decades, the mechanisms underlying GnRH pulse generation in hypothalamic neural networks remain elusive. Here, we demonstrate the ultradian rhythm of GnRH gene transcription in single GnRH neurons using cultured hypothalamic slices prepared from transgenic mice expressing a GnRH promoter-driven destabilized luciferase reporter. Although GnRH promoter activity in each GnRH neuron exhibited an ultradian pattern of oscillations with a period of ?10 h, GnRH neuronal cultures exhibited partially synchronized bursts of GnRH transcriptional activity at ?2-h intervals. Surprisingly, pulsatile administration of kisspeptin, a potent GnRH secretagogue, evoked dramatic synchronous activation of GnRH gene transcription with robust stimulation of pulsatile GnRH secretion. We also addressed the issue of hierarchical interaction between the circadian and ultradian rhythms by using Bmal1-deficient mice with defective circadian clocks. The circadian molecular oscillator barely affected basal ultradian oscillation of GnRH transcription but was heavily involved in kisspeptin-evoked responses of GnRH neurons. In conclusion, we have clearly shown synchronous bursts of GnRH gene transcription in the hypothalamic GnRH neuronal population in association with episodic neurohormone secretion, thereby providing insight into GnRH pulse generation.
| S-EPMC3619287 | biostudies-literature
Project description:Ovaries are sensitive to chemotherapy, which may lead to early depletion of primordial follicle reserve. One strategy for gonadal function preservation is temporary ovarian suppression with Gonadotropin Releasing Hormone agonists (GnRHa) during chemotherapy. To date, GnRHa protective mechanism of action remains not fully elucidated. We collected 260 immature cumulus cell-oocyte complexes (COC) from 111 women < 38 years old, with a normal ovarian reserve. The COC were randomly assigned to the following groups: a) control; culture with the addition of b) GnRHa; c) cyclophosphamide; d) cyclophosphamide plus GnRHa. After in vitro treatments, RNA and proteins were extracted from oocytes and cumulus cells (CC), separately. Potential effects of drugs were evaluated on GnRH receptors, apoptosis pathways, ceramide pathway, and glutathione synthesis by quantitative PCR and, whenever possible, by Western blot. Cyclophosphamide triggered activation of the extrinsic pathway of apoptosis mediated by BAX in CC. The co-administration of GnRHa inhibited the apoptosis pathway in CC. According to our model, the GnRHa does not directly act on oocytes, which do not express GnRH receptors. Moreover, glutathione synthesis was decreased after GnRHa treatment both in CC and oocytes. Our data suggest that the protective mechanisms induced by GnRHa is mediated by an anti-apoptotic effect on CC.
| S-EPMC6928931 | biostudies-literature
Project description:ObjectiveGonadotropin-releasing hormone agonist (GnRHa) treatment improves the potential for gaining height in patients with central precocious puberty (CPP). However, most studies have focused on girls because CPP in boys is relatively rare. Therefore, we aimed to determine the effect of GnRHa treatment on auxological outcomes in boys with CPP.MethodsEighty-five boys with CPP were treated with leuprolide or triptorelin acetate 3.75 mg over 2 years. Anthropometry, bone age, sexual maturity rating, and predicted adult height (PAH) were assessed every 6 months. Furthermore, 20 boys were followed up after treatment discontinuation until achievement of the final adult height (FAH).ResultsThe mean chronological age (CA) and bone age (BA) of the patients with CPP at treatment initiation were 9.5 ± 0.5 years and 11.7 ± 0.9 years, respectively. The mean duration of treatment was 2.87 ± 0.63 years. The PAH at treatment initiation was 172.1 cm (-0.23 ± 1.05 PAH standard deviation score). The PAH at treatment discontinuation (176.2 ± 6.6 cm) was significantly higher than the pretreatment PAH. In addition, the mean final adult height in the 20 boys who were followed up after discontinuation of treatment was 173.4 ± 5.8 cm, which was significantly higher than the initial PAH (170.1 ± 4.5 cm; p = 0.006). In multivariate analysis, the height gain (the difference between the FAH and PAH at treatment initiation) significantly correlated with the target height.ConclusionLong-term GnRHa treatment significantly improved the growth potential and FAH in boys with CPP.
| S-EPMC7728242 | biostudies-literature
Project description:OBJECTIVE:Gonadotropin-releasing hormone agonists (GnRHa) are the treatment of choice for central precocious puberty (CPP) and have been widely used for several decades. We determined the effect of GnRHa treatment on the auxological outcomes of girls with idiopathic CPP. METHODS:This study included 84 girls treated monthly with depot leuprolide acetate who had reached adult height. We compared their final adult height (FAH) with their initial predicted adult height (PAH). We performed a multivariate analysis of the factors associated with FAH on all girls diagnosed with CPP. RESULTS:We performed the final evaluations at a mean age of 14.1 ± 0.8 years after a mean treatment duration of 2.98 ± 0.73 years (ranging from 1.5-4.8 years). Menarche had occurred at 12.6 ± 0.6 years of age, which was 16.5 ± 6.1 months after discontinuation of GnRHa therapy. Mean FAH was 160.1 ± 5.0 cm, which was significantly higher than the initial PAH (156.1 ± 5.7 cm; P < 0.001). To investigate whether growth outcomes were influenced by the age at initial treatment, we divided all patients into two groups, those treated between 6 and 8 years (n = 23) and those treated after 8 years (n = 61); no significant differences were observed in FAH between the two groups. FAH was significantly and positively correlated with the height standard deviation score (SDS) at the end of treatment and with the target height, whereas the difference between bone age and chronological age at the start and end of treatment was negatively correlated with FAH. CONCLUSION:FAH was significantly higher than the initial PAH in girls with CPP who were treated with GnRHa. Also, GnRHa treatment was still effective even after 8 years of age in girls with CPP.
| S-EPMC6104939 | biostudies-literature
Project description:Study objectiveTo explore the potential occurrence of long-term side effects and tolerability of gonadotropin-releasing hormone agonist (GnRHa) plus 2 different add-back regimens in adolescent patients with endometriosis.DesignFollow-up questionnaire sent in 2016 to patients who participated in a drug trial between 2008 and 2012.SettingTertiary care center in Boston, Massachusetts.ParticipantsFemale adolescents with surgically confirmed endometriosis (n = 51) who enrolled in a GnRHa plus add-back trial as adolescents.InterventionsLeuprolide depot 11.25 mg intramuscular injection every 3 months, plus oral norethindrone acetate 5 mg daily or oral norethindrone acetate 5 mg daily and oral conjugated equine estrogens 0.625 mg daily.Main outcome measuresSide effects during and after treatment, irreversible side effects, changes in pain, overall satisfaction.ResultsThe response rate was 61% (25 of 41; 10 subjects could not be located). Almost all (24 of 25) reported side effects during treatment; 80% (16 of 21) reported side effects lasting longer than 6 months after stopping treatment. Almost half (9 of 20) reported side effects they considered irreversible, including memory loss, insomnia, and hot flashes. Despite side effects, participants rated GnRHa plus add-back as the most effective hormonal medication for treating endometriosis pain; two-thirds (16 of 25) would recommend it to others. More participants who received a modified 2-drug add-back regimen vs standard 1-drug add-back would recommend GnRHa and believed it was the most effective hormonal medication.ConclusionSubjects believed that GnRHa used with add-back was effective and would recommend it to others, despite significant side effects. Those who received 2-drug add-back reported more success than those who received standard add-back. A subset of patients reported side effects they consider to be irreversible.
| S-EPMC5997553 | biostudies-literature
Project description:Purpose: Up to 1.8% of youth identify as transgender; many will be treated with a gonadotropin-releasing hormone agonist (GnRHa). The impact of GnRHa on insulin sensitivity and body composition in transgender youth is understudied. We aimed to evaluate differences in insulin sensitivity and body composition in transgender youth on GnRHa therapy compared with cisgender youth. Methods: Transgender participants were matched to cisgender participants on age, body mass index, and sex assigned at birth. Transgender males (n=9, ages 10.1-16.0 years) on GnRHa (mean±standard deviation duration of exposure: 20.9±19.8 months) were compared with cisgender females (n=14, ages 10.6-16.2). Transgender females (n=8, ages 12.6-16.1) on GnRHa (11.3±7 months) were compared with cisgender males (n=17, ages 12.5-15.5). Differences in insulin sensitivity (1/[fasting insulin], homeostatic model of insulin resistance [HOMA-IR]), glycemia (hemoglobin A1C [HbA1c], fasting glucose), and body composition (dual-energy X-ray absorptiometry) were evaluated using a mixed linear regression model. Results: Transgender males had lower 1/fasting insulin and higher HOMA-IR (p=0.031, p=0.01, respectively), fasting glucose (89±4 vs. 79±13 mg/dL, p=0.012), HbA1c (5.4±0.2 vs. 5.2±0.2%, p=0.039), and percent body fat (36±7 vs. 32±5%, p=0.042) than matched cisgender females. Transgender females had lower 1/fasting insulin and higher HOMA-IR (p=0.028, p=0.035), HbA1c (5.4±0.1% vs. 5.1±0.2%, p=0.007), percent body fat (31±9 vs. 24±10%, p=0.002), and lower percent lean mass (66±8 vs. 74±10%, p<0.001) than matched cisgender males. Conclusion: Transgender youth on a GnRHa have lower estimated insulin sensitivity and higher glycemic markers and body fat than cisgender controls with similar characteristics. Longitudinal studies are needed to understand the significance of these changes. Clinical Trial.gov ID: NCT02550431.
| S-EPMC8080916 | biostudies-literature