Gonadotropin-releasing Hormone Levels Research Articles

Down regulation of the c-Fos/MAP kinase signaling pathway during learning memory processes coincides with low GnRH levels in aluminum chloride-induced Alzheimer's male rats.

Aluminum chloride (Al) is associated with Alzheimer's disease (AD) and reproductive disorders. But the relationship between gonadotropin-releasing hormone (GnRH) and c-Fos levels, the end product of MAP-kinase signaling, in AD is unknown, so we aimed to investigate this relationship. We exposed rats to Al dissolved in drinking water (10 and 50mg/kg) for two and four weeks. The control group received only drinking water. At the end, the blood sample was collected under deep anesthesia and the brain was dissected on ice, and the testicular tissue was fixed in formalin. Amyloid beta (βA) plaques in brain regions and the number of CA1 neurons were evaluated by Congo red staining and cresyl violet staining. Activation of neuronal nitric oxide synthase (nNOS) was studied using NADPH-diaphorase. The levels of c-Fos and testosterone receptors in the target area were examined immunohistochemically. Brain GnRH levels were determined by blotting, and serum levels of gonadotropins and steroids were measured by enzyme-linked immunosorbent assay (ELISA). All data were analyzed using analysis of variance (ANOVA) at α = 0.05 level. The accumulation of βA plaque was observed along with a decrease in the number of CA1 pyramidal neurons and a significant decrease in the levels of c-Fos and GnRH in the brains of rats receiving Al, which was aligned with a significant decrease in serum levels of testosterone and LH. This study, for the first time, showed a link between dementia and a concomitant decrease in brain GnRH and c-Fos levels.

Decreased Circulating Gonadotropin-Releasing Hormone Associated with Keratoconus.

Keratoconus (KC) is a corneal thinning dystrophy that leads to visual impairment. While the cause of KC remains poorly understood, changes in sex hormone levels have been correlated with KC development. This study investigated circulating gonadotropin-releasing hormone (GnRH) in control and KC subjects to determine if this master hormone regulator is linked to the KC pathology. Plasma and saliva were collected from KC subjects (n = 227 and n = 274, respectively) and non-KC controls (n = 58 and n = 101, respectively), in concert with patient demographics and clinical features. GnRH levels in both plasma and saliva were significantly lower in KC subjects compared to controls. This finding was retained in plasma when subjects were stratified based on age, sex, and KC severity. Control and KC corneal fibroblasts (HKCs) stimulated with recombinant GnRH protein in vitro revealed significantly increased luteinizing hormone receptor by HKCs and reduced expression of α-smooth muscle actin with treatment suggesting that GnRH may modulate hormonal and fibrotic responses in the KC corneal stroma. Further studies are needed to reveal the role of the hypothalamic-pituitary-gonadal axis in the onset and progression of KC and to explore this pathway as a novel therapeutic target.

8686 scRNA-seq of pituitary from letrozole-induced PCOS mouse model reveals abnormal prolactin secretion

Abstract Disclosure: G. De Robles: None. N. Ujagar: None. Z. Del Mundo: None. D. Nicholas: None. Polycystic ovary syndrome (PCOS) has a complex pathophysiology and is the most common endocrine disorder among reproductive-aged women. Ovarian hormonal dynamics are regulated via the secretion of the gonadotropin-releasing hormone (GnRH), which stimulates the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary gland. High serum levels of LH in PCOS patients indicate an increase in GnRH levels, but the mechanisms within the anterior pituitary at a cellular level are unclear. We performed single-cell mRNA sequencing (scRNA-seq) on the pituitaries of the letrozole-induced (LET) mouse model of PCOS to profile the functional genomics of endocrine cell populations relative to serum hormone levels. The population percentage of lactotropes significantly decreased; in contrast, two gonadotrope populations significantly increased in the LET mice compared to the placebo-treated mice. Consistent with these changes, an increasing trend of serum LH levels and a decreasing trend of serum prolactin (PRL) levels were observed in the LET mice, while no change occurred in serum growth hormone levels. A gene set enrichment analysis (GSEA) on the differentially expressed genes (DEGs) from the lactotropes revealed an association with negative regulation of protein kinase activity. These DEGs included Hspb1, Park7, Pcp4, and Ppia, which all share the function of mediating stress-induced apoptosis. A GSEA on the DEGs between the two gonadotrope clusters in the LET mice also confirmed a variation in biological pathways linked to ribosomal subunits, transcription regulation, and the regulation of steroid metabolic processes. Based on the scRNA-seq results of the anterior pituitaries of LET mice, alterations in the proportions of hormone-secreting cells may be a response to hyperandrogenism, in which functionally diverse gonadotropes could contribute to heterogeneity in reproductive phenotypes. Changes in the lactotrope population and PRL serum levels also support further research on the lactation hormone and its role in PCOS. PRL is involved in metabolic homeostasis and reproduction, and understanding its dysregulations may provide additional insight into the pathophysiology of PCOS. Presentation: 6/3/2024

Diversity of Molecular Functions of RNA-Binding Ubiquitin Ligases from the MKRN Protein Family.

Makorin RING finger protein family includes four members (MKRN1, MKRN2, MKRN3, and MKRN4) that belong to E3 ubiquitin ligases and play a key role in various biological processes, such as cell survival, cell differentiation, and innate and adaptive immunity. MKRN1 contributes to the tumor growth suppression, energy metabolism, anti-pathogen defense, and apoptosis and has a broad variety of targets, including hTERT, APC, FADD, p21, and various viral proteins. MKRN2 regulates cell proliferation, inflammatory response; its targets are p65, PKM2, STAT1, and other proteins. MKRN3 is a master regulator of puberty timing; it controls the levels of gonadotropin-releasing hormone in the arcuate nucleus neurons. MKRN4 is the least studied member of the MKRN protein family, however, it is known to contribute to the Tcell activation by ubiquitination of serine/threonine kinase MAP4K3. Proteins of the MKRN family are associated with the development of numerous diseases, for example, systemic lupus erythematosus, central precocious puberty, Prader-Willi syndrome, degenerative lumbar spinal stenosis, inflammation, and cancer. In this review, we discuss the functional roles of all members of the MKRN protein family and their involvement in the development of diseases.

Impact of polyamine supplementation on GnRH expression, folliculogenesis, and puberty onset in young mice

BackgroundThe hypothalamic-pituitary-gonadal (HPG) axis is pivotal in regulating reproductive functions, with gonadotropin-releasing hormone (GnRH) acting as a central regulator. Recently, polyamines have been shown to regulate the HPG axis, including GnRH expression and ovarian biology in old and adult rodents. The present study firstly highlights the age-specific variation in the polyamine and their corresponding biosynthetic enzymes in the ovary during aging, and further, the study focuses on the effect of polyamines, putrescine, and agmatine, in young female mice. Method and resultImmunofluorescence analysis revealed age-related differences in the expression of ornithine decarboxylase 1 (ODC1), spermine (SPM), and spermidine (SPD) in the ovaries, with adult mice exhibiting significantly higher expression levels compared to young and old mice. Likewise, qPCR analysis showed the mRNA levels of Odc1, Spermidine synthase (Srm), and Spermine synthase (Sms) show a significant increase in adult ovaries, which is then followed by a significant decline in old age. Histological examination demonstrated morphological alterations in the ovaries with age, including decreased follicle numbers and increased stromal cells in old mice. Furthermore, treatment with putrescine, a polyamine, in young mice resulted in larger ovaries and increased follicle numbers compared to controls. Additionally, serum levels of gonadotropin-releasing hormone (GnRH) and progesterone (P4) were measured, showing elevated levels in polyamine-treated mice. GnRH mRNA expression also increased significantly. Gene expression analysis revealed upregulation of genes associated with folliculogenesis such as Fshr, Bmp15, Gdf9, Amh, Star, Hsdb3, and Plaur in the ovaries and onset of puberty such as Tac2, and Kiss1, and a decrease in Mkrn3 in the hypothalamus of polyamine-treated mice. ConclusionThis study investigates the effect of polyamines in young immature female mice, shedding light on their role in upregulating GnRH, and enhancing folliculogenesis. Overall, these findings suggest that polyamines play a crucial role in ovarian aging and HPG axis regulation, offering potential therapeutics to reinstate fertility in reproductively challenged individuals.

Direct Feedback Regulation of E2, T, and hCG in the Brain–Pituitary–Gonad Axis of Japanese Eel (Anguilla japonica) during Artificial Maturation

The feedback regulatory effects of estrogen (E2) and androgen (T) on the gonadotropin-releasing hormone (GnRH) and gonadotropin (GtH) within the brain–pituitary–gonad (BPG) axis in eels with undeveloped ovaries were investigated through in vivo studies. However, the regulatory role of the BPG axis only became apparent during ovary development in the migratory stage. To further elucidate the direct feedback regulation of the BPG axis, female Anguilla japonica underwent artificial induction of vitellogenesis, and the regulation of BPG axis tissues by GtH (human chorionic gonadotropin, hCG), E2, and T was explored through in vitro exposure. The mRNA expression levels of GnRH (mGnRH), GtH (fshb and lhb), and steroid biosynthesis enzymes (cyp11a1, hsd3b, cyp17a1, and cyp17a2) in the diencephalon, pituitary, and ovary, respectively, were determined. The results showed that the expression level of mGnRH in the diencephalon was significantly downregulated by 0.1 IU/mL hCG but upregulated by both 1 nM E2 and higher concentrations of T, suggesting a direct positive feedback regulation of E2 on mGnRH. In the pituitary, the expression levels of fshb and lhb were upregulated by E2, while fshb was suppressed by T. In the ovaries, the expression of cyp11a1 and hsd3b was upregulated by 1 nM E2, whereas T exposure resulted in an opposite effect. Cyp17a1 mRNA levels did not differ significantly with E2 treatment but were upregulated by 1 nM T. These findings suggest that low concentrations of E2 exhibited positive feedback regulation on all three levels (diencephalon, pituitary, and ovary) of the BPG axis, while T showed weaker and differential feedback regulation in BPG axis tissues. Overall, this study’s results revealed the direct feedback regulation of hCG, E2, and T on the BPG axis in eels, a phylogenetic base of teleosts.

Reversible Sterilization of Channel Catfish via Overexpression of Glutamic Acid Decarboxylase Gene.

The confinement of transgenic fish is essential to prevent their escape and reproduction in natural ecosystems. Reversible transgenic sterilization is a promising approach to control the reproduction of transgenic fish. Therefore, the present study was conducted to develop a reversibly sterile channel catfish (Ictalurus punctatus) via the transgenic overexpression of the goldfish (Carassius auratus) glutamic acid decarboxylase (GAD) gene driven by the common carp (Cyprinus carpio) β-actin promoter to disrupt normal gamma-aminobutyric acid (GABA) regulation. Three generations of GAD-transgenic fish were produced. All studied generations showed repressed reproductive performance; however, this was not always statistically significant. In F1, 5.4% of the transgenic fish showed a sexual maturity score ≥ 4 (maximum = 5) at five years of age, which was lower (p = 0.07) than that of the control group (16.8%). In the spawning experiments conducted on F1 transgenic fish at six and nine years of age, 45.5% and 20.0% of fish spawned naturally, representing lower values (p = 0.09 and 0.12, respectively) than the percentages in the sibling control fish of the same age (83.3% and 66.7%, respectively). Four of six pairs of the putative infertile six-year-old fish spawned successfully after luteinizing hormone-releasing hormone analog (LHRHa) therapy. Similar outcomes were noted in the three-year-old F2 fish, with a lower spawning percentage in transgenic fish (20.0%) than in the control (66.7%). In one-year-old F2-generation transgenic fish, the observed mean serum gonadotropin-releasing hormone (GnRH) levels were 9.23 ± 2.49 and 8.14 ± 2.21 ng/mL for the females and males, respectively. In the control fish, the mean levels of GnRH were 11.04 ± 4.06 and 9.03 ± 2.36 ng/mL for the females and males, respectively, which did not differ significantly from the control (p = 0.15 and 0.27 for females and males, respectively). There was no significant difference in the estradiol levels of the female transgenic and non-transgenic fish in the one- and four-year-old F2-generation fish. The four-year-old F2-generation male transgenic fish exhibited significantly (p < 0.05) lower levels of GnRH and testosterone than the control fish. In conclusion, while overexpressing GAD repressed the reproductive abilities of channel catfish, it did not completely sterilize transgenic fish. The sterilization rate might be improved through selection in future generations.

The Effect of Prolactin on Gene Expression and the Secretion of Reproductive Hormones in Ewes during the Estrus Cycle.

Prolactin (PRL) plays an important role in animal follicle development and ovulation. However, its regulatory effects on the different stages of the estrus cycle in ewes are unclear. In this study, bromocriptine (BCR, PRL inhibitor) was used to study the effect of PRL on the secretion of reproductive hormones and gene expressions in order to explore its regulatory effects on the sexual cycle of ewes. Eighty healthy ewes with the same parity and similar weights were randomly assigned to the control group (C, n = 40) and the treatment group (T, n = 40, fed bromocriptine). After estrus synchronization, thirty-one ewes with overt signs of estrus were selected from each group. Six blood samples were randomly obtained by jugular venipuncture to measure the concentration of PRL, estrogen (E2), progesterone (P4), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and gonadotropin-releasing hormone (GnRH) in the proestrus, estrus, metestrus, and diestrus. At the same time, we collected the ovaries of the six ewes in vivo after anesthesia in order to detect follicle and corpus luteum (CL) counts and measure the expression of hormone-receptor and apoptosis-related genes. The results show that PRL inhibition had no significant effects on the length of the estrus cycle (p > 0.05). In proestrus, the number of large and small follicles, the levels of E2, FSH, and GnRH, and the expressions of ER, FSHR, and the apoptotic gene Caspase-3 were increased (p < 0.05); and the number of middle follicles and the expression of anti-apoptotic gene Bcl-2 were decreased (p < 0.05) in the T group. In estrus, the number of large follicles, the levels of E2 and GnRH, and the expressions of the StAR, CYP19A1, and Bcl-2 genes were increased (p < 0.05), and the number of middle follicles was decreased (p < 0.05) in the T group. In metestrus, the number of small follicles and the expression of LHR (p < 0.05) and the pro-apoptotic gene Bax were increased (p < 0.05); the number of middle follicles was decreased (p < 0.05) in the T group. In diestrus, the number of large follicles, middle follicles, and CL, the level of P4, and the expressions of PR, 3β-HSD, StAR, Caspase-3, and Bax were increased (p < 0.05); the number of small follicles and the expression of Bcl-2 were decreased (p < 0.05) in the T group. In summary, PRL inhibition can affect the secretion of reproductive hormones, the follicle count, and the gene expression during the estrus cycle. These results provide a basis for understanding the mechanisms underlying the regulation of the ewe estrus cycle by PRL.

The effect of aqueous extract of orchid root on the structure of ovary and hypothalamic-pituitary-gonadal hormones in polycystic ovary syndrome rat model: An experimental study.

Some medical conditions, including polycystic ovarian syndrome (PCOs), may lead to infertility. In PCOs, hormonal imbalance is significant. Antioxidants such as natural antioxidants have many health benefits, including positive effects on hormone production. Since herbal medicines are more acceptable to people, the present study was designed to evaluate the effect of an aqueous extract of orchid (SA), with antioxidative effects, on the structure of the ovary and the hypothalamic-pituitary-gonadal axis hormones and free testosterone in PCOs rats. In this experimental study, 64 healthy female Wistar rats (180-200 gr) were randomly divided into 60 and 89 day control groups, PCOs, and 4 PCOs + SA groups that received 40, 80, 160, and 320 mg/kg of SA. Serum levels of gonadotropin-releasing hormone, estrogen, progesterone, testosterone, follicle-stimulating hormone, and luteinizing hormone were measured. In addition, the ovaries were extracted and examined histologically. The amount of primordial, primary, secondary, and Graafian follicles and serum levels of follicle-stimulating hormone and progesterone hormones decreased in PCOs groups, while atretic follicles and the serum levels of gonadotropin-releasing hormone, luteinizing hormone, estrogen, and free testosterone were increased. SA at different doses regulated hormonal and histological imbalances caused by PCOs, and 320 mg/kg was the most effective. The aqueous extract of orchids root can have a positive effect on the improvement of polycystic ovary syndrome. This effect can be achieved by regulating the level of sex hormones and correcting follicular abnormalities in the ovarian tissue.

Impact of Short-Term Arsenic Exposure on Hormonal Balance and Fibrosis in Sprague Dawley Rats

Objective: To evaluate the toxic effects of arsenic exposure on the female reproductive tract and endocrinesystem.Study Design: A laboratory-based experiment.Place and Duration of Study: The study was carried out at the Laboratory of the National Institute of Health(NIH) Islamabad, Pakistan from 1st January 2019 to 4th January 2020.Methods: non-probability convenient sampling technique was employed and 60 female healthy SpragueDawley rats were included in the study at the National Institute Islamabad. Animals were randomly allocatedinto control and experimental groups (n=30 each). In the first week, animals were acclimatized to the animalhouse of the College of Physicians and Surgeons Pakistan. In the second week, the control and experimentalgroups were given 10 ml of distilled water by oral gavage daily and 4μg of sodium arsenite dissolved in 10 ml ofdistilled water daily for two weeks respectively. After the experimental period, animals were taken to theanimal lab of the National Institute of Health Islamabad for blood sampling and tissue dissection. Rats wereeuthanized by chloroform inhalation and blood was drawn by single intracardiac puncture and stored in clotactivator vials at 4 0C for further workup. The female reproductive tract was dissected, and the tissue was stored in 10 % formalin for histological studies. Serum Gonadotropin-releasing hormone (GnRH) levels were assessed via the Enzyme-Linked Immunosorbent Assay (ELISA) method. Whereas histological effects of arsenic were observed under a microscope by tissue processing and staining with Masson trichrome stain. Mean ± SD of serum GnRH levels and percentage of fibrosis in uterine tissue of control and experimental groups wereevaluated by the software Statistical Package for Social Sciences version 22.0. Comparison of means evaluatedby Student T-test. The significant p-value was ≤ 0.05.Results: The experimental group showed significant elevation of serum GnRH levels and fibrotic changes withhigh collagen deposition (p ≤ 0.05).Conclusion: Exposure to arsenic via contaminated drinking water is disruptive for the female reproductive tractand endocrine system. How to cite this: Mir A, Mir UZ, Hussain W, Irfan A, Butt HA, Sarwar U. Impact of Short-Term Arsenic Exposure on Hormonal Balance and Fibrosis in Sprague Dawley Rats. Life and Science. 2024; 5(2): 187-192. doi: http://doi.org/10.37185/LnS.1.1.64

The Involvement of the microRNAs miR-466c and miR-340 in the Palmitate-Mediated Dysregulation of Gonadotropin-Releasing Hormone Gene Expression.

Diets high in saturated fatty acids are associated with obesity and infertility. Palmitate, the most prevalent circulating saturated fatty acid, is sensed by hypothalamic neurons, contributing to homeostatic dysregulation. Notably, palmitate elevates the mRNA levels of gonadotropin-releasing hormone (Gnrh) mRNA and its activating transcription factor, GATA binding protein 4 (Gata4). GATA4 is essential for basal Gnrh expression by binding to its enhancer region, with Oct-1 (Oct1) and CEBP-β (Cebpb) playing regulatory roles. The pre- and post-transcriptional control of Gnrh by palmitate have not been investigated. Given the ability of palmitate to alter microRNAs (miRNAs), we hypothesized that palmitate-mediated dysregulation of Gnrh mRNA involves specific miRNAs. In the mHypoA-GnRH/GFP neurons, palmitate significantly downregulated six miRNAs (miR-125a, miR-181b, miR-340, miR-351, miR-466c and miR-503), and the repression was attenuated by co-treatment with 100 μM of oleate. Subsequent mimic transfections revealed that miR-466c significantly downregulates Gnrh, Gata4, and Chop mRNA and increases Per2, whereas miR-340 upregulates Gnrh, Gata4, Oct1, Cebpb, and Per2 mRNA. Our findings suggest that palmitate may indirectly regulate Gnrh at both the pre- and post-transcriptional levels by altering miR-466c and miR-340, which in turn regulate transcription factor expression levels. In summary, palmitate-mediated dysregulation of Gnrh and, consequently, reproductive function involves parallel transcriptional mechanisms.

Aspartame Intake Delayed Puberty Onset in Female Offspring Rats and Girls.

The disturbance of the hypothalamic-pituitary-gonadal (HPG) axis, gut microbiota (GM) community, and short-chain fatty acids (SCFAs) is a triggering factor for pubertal onset. The study investigates the effects of the long-term intake of aspartame on puberty and GM in animals and humans. Aspartame-fed female offspring rats result in vaginal opening time prolongation, serum estrogen reduction, and serum luteinizing hormone elevation. , 60mgkg-1 aspartame treatment decreases the mRNA levels of gonadotropin-releasing hormone (GnRH), Kiss1, and G protein-coupled receptor 54 (GPR54), increases the mRNA level of RFamide-related peptide-3 (RFRP-3), and decreases the expression of GnRH neurons in the hypothalamus. Significant differences in relative bacterial abundance at the genus levels and decreased fecal SCFA levels are noted by 60mgkg-1 aspartame treatment. Among which, Escherichia-Shigella is negatively correlated with several SCFAs. In girls, high-dose aspartame consumption decreases the risk of precocious puberty. Aspartame reduces the chance of puberty occurring earlier than usual in female offspring and girls. Particularly, 60mgkg-1 aspartame-fed female offspring delays pubertal onset through the dysregulation of HPG axis and GM composition by inhibiting the Kiss1/GPR54 system and inducing the RFRP-3. An acceptable dose of aspartame should be recommended during childhood.

Modulating the RFamide-related peptide-3/G protein-coupled receptor 147 signaling pathway with nourishing Yin-removing fire herbal mixture to alleviate precocious puberty in female rats: An experimental study.

Precocious puberty (PP) involves early activation of the hypothalamic gonadotropin-releasing hormone (GnRH) generator. The RFamide-related peptide/G protein-coupled receptor 147 (RFRP3/GPR147) signaling pathway is vital in inhibiting GnRH and delaying puberty onset. The nourishing Yin-removing fire (NYRF) herbal mixture has shown promising results in treating PP. This study aimed to assess the impact of the NYRF herbal mixture on the RFRP3/GPR147 signaling pathway in the hypothalamus and its potential in alleviating PP in female rats. In a controlled experiment, 24 female Sprague-Dawley rats (11.20 0.69 gr, postnatal day [PD5]) were divided into normal, model, normal saline, and NYRF groups (n = 6/each). PP was induced in the model, normal saline, and NYRF groups by subcutaneous injection of danazol at PD5. The NYRF herbal mixture or normal saline was administered from PD15. Serum sex hormone levels and hypothalamic samples were collected for mRNA and protein expression at PD30. In the model group, hypothalamic GnRH and kisspeptin levels increased, while RFRP3 and GPR147 levels decreased, luteinizing hormone levels elevated, reproductive organ coefficients increased, and the vagina opened earlier compared to the normal group. Conversely, the NYRF group exhibited lower GnRH and kisspeptin levels but higher RFRP3 levels in the hypothalamus. Serum luteinizing hormone levels were reduced, reproductive organ coefficients were reduced, and the vaginal opening was delayed compared to the model and normal saline groups. The NYRF herbal mixture delayed sexual development in rats with PP by hypothalamic upregulating RFRP3 and downregulating GnRH and kisspeptin.

Characterization of MicroRNA expression profiles in the ovarian tissue of goats during the sexual maturity period

BackgroundThe ovary is an important reproductive organ in mammals, and its development directly affects the sexual maturity and reproductive capacity of individuals. MicroRNAs (miRNAs) are recognized as regulators of reproductive physiological processes in various animals and have been shown to regulate ovarian development through typical targeting and translational repression. However, little is known about the regulatory role of miRNAs in ovarian tissue development during sexual maturity in goats. To comprehensively profile the different physiological stages of sexual maturation in goats, we performed small-RNA sequencing of ovarian tissue samples collected at four specific time points (1 day after birth (D1), 2 months old (M2), 4 months old (M4), and 6 months old (M6)). In addition, we used ELISAs to measure serum levels of reproductive hormones to study their temporal changes.ResultsThe results showed that serum levels of gonadotropin-releasing hormone, follicle-stimulating hormone, luteinizing hormone, oestradiol, progesterone, oxytocin, and prolactin were lower in goats at the D1 stage than at the other three developmental stages (P < 0.05). The secretion patterns of these seven hormones show a similar trend, with hormone levels reaching their peaks at 4 months of age. A total of 667 miRNAs were detected in 20 libraries, and 254 differentially expressed miRNAs and 3 groups of miRNA clusters that had unique expression patterns were identified (|log2-fold change|> 1, FDR < 0.05) in the 6 comparison groups. RT‒qPCR was employed to confirm that the expression pattern of the 15 selected miRNAs was consistent with the Illumina sequencing results. Gene ontology analyses revealed significant enrichment of GO terms such as cell proliferation regulation, epithelial cell development, and amino acid transport, as well as important signaling pathways including the MAPK signaling pathway, the PI3K-Akt signaling pathway, and the oestrogen signaling pathway. Further miRNA‒mRNA regulation network analysis revealed that 8 differentially expressed miRNAs (chi-miR-1343, chi-miR-328-3p, chi-miR-877-3p, chi-miR-296-3p, chi-miR-128-5p, chi-miR-331-3p, chi-miR-342-5p and chi-miR-34a) have important regulatory roles in ovarian cell proliferation, hormone secretion and metabolism-related biological processes.ConclusionsOverall, our study investigated the changes in serum hormone and miRNA levels in the ovaries. These data provide a valuable resource for understanding the molecular regulatory mechanisms of miRNAs in ovarian tissue during the sexual maturity period in goats.

Unlocking cognition with pulsatile GnRH in Down Syndrome: implications for Alzheimer’s disease

AbstractBackgroundThere is currently no viable treatment for the cognitive and olfactory deficits of Trisomy 21 and Alzheimer’s disease.MethodPhysiological characterization and epigenetic, cellular, chemogenetic, and pharmacological interventions in male and female Ts65Dn mice (P9‐P360), a mouse model of Down syndrome, and 12‐month‐old THY::TAU22 male mice, a mouse model of Alzheimer’s disease, and their wild‐type littermates. Seven men with Down syndrome (20‐50 years of age) were enrolled in an open‐label pilot study to assess the effect of 6‐month pulsatile GnRH therapy on cognitive and olfactory function.ResultWe show in Ts65Dn mice that olfactory and cognitive neurological symptoms are closely related to a post‐pubertal decrease in hypothalamic and extra‐hypothalamic expression of a master molecule controlling reproduction ‐ gonadotropin‐releasing hormone (GnRH) ‐ and appear to be linked to an imbalance in a microRNA‐gene network known to regulate the maturation of GnRH neurons as well as to an alteration in hippocampal synaptic transmission. Restoring physiological GnRH levels abolishes olfactory and cognitive deficits in Ts65Dn and THY::TAU22 mice, while pulsatile GnRH treatment improves cognition and brain connectivity in adult T21 patients.ConclusionWe have discovered that GnRH plays a crucial role in olfaction and cognition, and pulsatile GnRH treatment holds promise for improving cognitive deficits in patients with Down syndrome. Such treatment could potentially also be beneficial for mobilizing cognitive reserve in pathological brain aging such as that found in Alzheimer’s disease.

Effects of trichlorobisphenol A on the expression of proteins and genes associated with puberty initiation in GT1-7 cells and the relevant molecular mechanism

This study evaluated the effects of Cl3BPA on kisspeptin-G-protein coupled receptor 54 (GPR54)/gonadotropin-releasing hormone (GnRH) (KGG) signals and analyzed the roles of estrogen receptor alpha (ERɑ) and G-protein coupled estrogen receptor 1 (GPER1) in regulating KGG signals. The results showed that Cl3BPA at 50 μM increased the levels of intracellular reactive oxygen species (ROS) and GnRH, upregulated the protein levels of kisspeptin and the expression of fshr, lhr and gnrh1 genes related to KGG in GT1-7 cells. In addition, 50 μM Cl3BPA significantly upregulated the phosphorylation of extracellular regulated protein kinases 1/2 (Erk1/2), the protein levels of GPER1 and the expression of the gper1 as well as the most target genes associated with mitogen-activated protein kinase (MAPK)/Erk1/2 pathways. Specific signal inhibitor experiments found that Cl3BPA activated KGG signals by activating the GPER1-mediated MAPK/Erk1/2 signaling pathway at the mRNA level. A docking test further confirmed the interactions between Cl3BPA and GPER1. The findings suggest that Cl3BPA might induce precocious puberty by increasing GnRH secretion together with KGG signaling upregulation, which is driven by GPER1-mediated signaling pathway. By comparison, ClxBPAs with fewer chlorine atoms had more obvious effects on the expression of proteins and partial genes related to KGG signals in GT1-7 cells.

Postnatal feeding with high-fat combined with high-glucose diet induces precocious puberty in Sprague‒Dawley rat pups

With economic development and overnutrition, including high-fat diets (HFD) and high-glucose diets (HGD), the incidence of obesity in children is increasing, and thus, the incidence of precocious puberty is increasing. Therefore, it is of great importance to construct a suitable animal model of overnutrition-induced precocious puberty for further in-depth study. Here, we fed a HFD, HGD, or HFD combined with a HGD to pups after P-21 weaning, while weaned pups fed a normal diet served as the control group. The results showed that HFD combined with a HGD increased the body weight (BW) of weaned rat pups. In addition, a HFD, HGD, and HFD combined with a HGD lowered the age at which vaginal opening occurred and accelerated the vaginal cell cycle. Furthermore, a HFD combined with a HGD increased the weight of the uterus and ovaries of weaned rat pups. Additionally, a HFD combined with a HGD promoted the development of reproductive organs in weaned female rat pups. Ultimately, a HFD combined with a HGD was found to elevate the serum levels of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle stimulating hormone (FSH), leptin, adiponectin, and oestradiol (E2) and increase hypothalamic GnRH, Kiss-1, and GPR54 expression levels in weaned female rat pups. The current study found that overnutrition, such as that through a HFD combined with HGD, could induce precocious puberty in weaned female rat pups. In addition, a rat model of overnutrition-induced precocious puberty was established.

Synergistic Action of Virgin Coconut Oil and Clomiphene in Reversing Endocrine Dysregulation in Letrozole-Model of Polycystic Ovarian Syndrome in Rats: Role of Nrf2/HMOX-1 Pathway.

Polycystic ovarian syndrome (PCOS) is an endocrine disorder in women's reproductive age. Currently, the pathophysiology of PCOS is unclear, and the limited treatment options are unsatisfactory. Virgin coconut oil (VCO) is functional food oil associated with pharmacological effects in reproductive disorders. Therefore, we aimed to evaluate whether VCO could enhance clomiphene (CLO) therapy against PCOS in female rats. Rats were randomly divided: (1) Control, (2) PCOS model, (3) PCOS + CLO, (4) PCOS + VCO, and (5) PCOS + CLO + VCO. The PCOS was induced via daily letrozole (1 mg/kg, orally) administration for 21 days. After the PCOS induction, CLO, VCO, and CLO + VCO were administered from days 22 to 36. Serum levels of gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, estrogen, progesterone, and prolactin were estimated. Polymerase chain reaction gene expression for nuclear factor-erythroid-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), catalase (CAT), glutathione reductase (GSR), LH receptor (LHr), androgen receptor (AR), tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and caspase-3 were analyzed. The letrozole-induced PCOS caused considerable increases in GnRH, LH, prolactin, estrogen, and testosterone, whereas FSH decreased significantly compared to the control. The gene expression of Nrf2, HO-1, CAT, and GSR were markedly diminished, while IL-1β, TNF-α, caspase-3, AR, and LHr prominently increased compared to control. Interestingly, the CLO and VCO separately exerted anti-inflammatory and endocrine balance effects. However, VCO-enhanced CLO effect in LH, prolactin and testosterone, Nrf2, HO-1, CAT, GSR, and AR. VCO may synergize with CLO to depress hyperandrogenism and oxidative inflammation in PCOS.

Effect of exercise on the hypothalamic–pituitary–gonadal axis in a rat model of Alzheimer’s disease

Hypothalamic–pituitary–gonadal (HPG) axis dysregulation was suggested to play a crucial role in Alzheimer’s disease (AD). This study investigated the effects of exercise on HPG hormones in an AD rat model, as a possible mechanism underlying the favorable effect of exercise on AD. Forty male Wistar albino rats 2–3 months old were subdivided randomly into two groups (n = 20 each): AD group (injected intraperitoneally with aluminum chloride (70 mg/kg/day) for 6 weeks) and Control group. Each group was subdivided into exercised or non-exercised group (n = 10 each). Exercised groups were subjected to a swimming protocol (60 min/day, 5 days/week, 4 weeks). Serum HPG hormones, hippocampal β-amyloid levels and Morris water-maze cognition were assessed. Results demonstrated higher levels of β-amyloid, gonadotropin releasing hormone (GnRH), luteinizing hormone (LH) and follicle stimulating hormone (FSH) together with lower testosterone levels and cognitive impairment in the AD rats compared to controls. Β-amyloid levels negatively correlated with testosterone levels and positively correlated with GnRH, LH and FSH among the AD rats. Higher testosterone and lower GnRH, LH, FSH and β-amyloid levels, as well as cognitive improvement, were observed in the exercised compared to non-exercised AD rats, suggesting a modulatory role of exercise training on AD-associated HPG axis dysregulation.

A role for GnRH in olfaction and cognition: Implications for veterinary medicine.

Pulsatile secretion of gonadotropin-releasing hormone (GnRH) is essential for the activation and maintenance of the function of the hypothalamic-pituitary-gonadal (HPG) axis, which controls the onset of puberty and fertility. Two provocative recent studies suggest that, in addition to control reproduction, the neurons in the brain that produce GnRH are also involved in the control postnatal brain maturation, odour discrimination and adult cognition. Long-acting GnRH antagonists and agonists are commonly used to control fertility and behaviour in veterinary medicine, primarily in males. This review puts into perspective the potential risks of these androgen deprivation therapies and immunization on olfactory and cognitive performances and well-aging in domestic animals, including pets. We will also discuss the results reporting beneficial effects of pharmacological interventions restoring physiological GnRH levels on olfactory and cognitive alterations in preclinical models of Alzheimer's disease, which shares many pathophysiological and behavioural hallmarks with canine cognitive dysfunction. These novel findings raise the intriguing possibility that pulsatile GnRH therapy holds therapeutic potential for the management of this behavioural syndrome affecting older dogs.