Search Results (112)

The activation mechanism of the reproductive axis in Kazakh ewes during the non-breeding season was explored by supplementation with glycerol complex (7% glycerol + tyrosine + vitamin B9). The experiment divided 50 ewes into five groups (n = 10). After 90 days of intervention, it was found that significant changes in serum DL-carnitine, N-methyl-lysine and other differential metabolites were observed in the GLY-Tyr-B9 group (p < 0.05, “p < 0.05” means significant difference, “p < 0.01” means “highly significant difference”). The bile acid metabolic pathway was specifically activated (p < 0.01). The group had a 50% estrus rate, ovaries contained 3–5 immature follicles, and HE staining showed intact granulosa cell structure. Serum E2/P4 fluctuated cyclically (p < 0.01), FSH/LH pulse frequency increased (p < 0.01), peak Glu/INS appeared on day 60 (p < 0.05), and LEP was negatively correlated with body fat percentage (p < 0.01). Molecular mechanisms revealed: upregulation of hypothalamic kiss-1/GPR54 expression (p < 0.01) drove GnRH pulses; ovarian CYP11A1/LHR/VEGF synergistically promoted follicular development (p < 0.05); the HSL of subcutaneous fat was significantly increased (p < 0.05), suggesting involvement of lipolytic supply. Glycerol activates the reproductive axis through a dual pathway—L-carnitine-mediated elevation of mitochondrial β-oxidation efficacy synergizes with kisspeptin/GPR54 signalling enhancement to re-establish HPO axis rhythms. This study reveals the central role of metabolic reprogramming in regulating seasonal reproduction in ruminants. Full article

Background/Objectives: The anti-Müllerian hormone (AMH) is a key biomarker of the ovarian reserve, correlating with ovarian follicle count, fertility outcomes, and menopause timing. Understanding its genetic determinants has broad implications for female reproductive health. However, prior genome-wide association studies (GWASs) have focused exclusively on women of European ancestry, limiting insights into diverse populations. Methods: We conducted a GWAS to identify genetic loci associated with circulating AMH levels in a sample of 1185 Samoan women from two independently recruited samples. Using a Cox mixed-effects model we accounted for AMH levels below detectable limits and meta-analysed the summary statistics using a fixed-effect model. To prioritize variants and genes, we used FUMA and performed colocalization and transcriptome-wide association analysis (TWAS). We also assessed whether any previously reported loci were replicated in our GWAS. Results: We identified eleven genome-wide suggestive loci, with the strongest signal at ARID3A (19-946163-G-C; p = 2.32 × 10⁻⁷) and replicated rs10093345 near EIF4EBP1. The gene-based testing revealed ARID3A and R3HDM4 as significant genes. Integrating GWAS results with expression quantitative trait loci via TWAS, we detected seven transcriptome-wide significant genes. The lead variant in ARID3A is in high linkage disequilibrium (r² = 0.79) with the known age-at-menopause variant 19-950694-G-A. Nearby KISS1R is a biologically plausible candidate gene that encodes the kisspeptin receptor, a regulator of ovarian follicle development linked to AMH levels. Conclusions: This study expands our understandings of AMH genetics by focusing on Samoan women. While these findings may be particularly relevant to Pacific Islanders, they hold broader implications for reproductive phenotypes such as the ovarian reserve, menopause timing, and polycystic ovary syndrome. Full article

Kisspeptin (Kiss1) and kisspeptin 1 receptor (Kiss1R) are vital in regulating various functions across many species, primarily those relating to reproduction. The kisspeptin system has recently attracted clinical interest as a potential therapeutic treatment for patients with hypoactive sexual desire disorder. This study maps the distribution of Kiss1 and Kiss1R mRNA in the Syrian hamster forebrain using dual-labeled RNAscope. In our study, the distributions of kisspeptin and its receptor were mapped across adult males and females on day 1 or day 2 of their estrous cycle. Conditioned place preference was used to observe the potential effect of kisspeptin on sexual reward in female hamsters. The expression of kisspeptin was greater in females than males, with the estrous cycle having no effect on expression. A comparison of these findings to those in other species revealed that the expression in Syrian hamsters was similar to that reported for other species, demonstrating the conservation of expression. Kisspeptin did not influence sexual reward in females, nor did it affect measures of their primary sexual behavior. These findings provide additional insights into the expression and function of kisspeptin across novel species and add to ongoing research in understanding how kisspeptin may influence sexual desire in animals, including humans. Full article

This overview explores the complex relationship between environmental factors, particularly obesity, and the timing of puberty, with a focus on how hormonal and genetic interactions are influenced by external conditions. Puberty (gonadarche) is characterised by the activation of the hypothalamic–pituitary–gonadal (HPG) axis. The onset and progression of puberty vary significantly among individuals, primarily due to genetic factors, with key genes like kisspeptin 1 (KISS1) and makorin ring finger protein 3 (MKRN3) playing a crucial role. Cohesively, this paper emphasises that environmental factors, particularly obesity and exposure to endocrine-disrupting chemicals (EDCs), have become significant influences on the timing of puberty. Childhood obesity has risen significantly in recent decades and the age of pubertal onset has declined over the same period. Obesity greatly disrupts hormone regulation in pre-pubertal children. Leptin accelerates the onset of puberty in girls but not in boys. The underlying mechanism is proposed to be the increase in Kiss1/GnRH signalling. On the contrary, excess leptin in boys suppresses testosterone production by increasing oestrogen conversion. Low adiponectin in obese girls may contribute to earlier puberty due to a reduced inhibition of Kiss1/GnRH signalling. Low adiponectin in boys is linked to delayed puberty due to its role in maintaining insulin sensitivity and testosterone production. Hyperinsulinemia influences pubertal timing through central and peripheral mechanisms. Insulin acting synergistically with leptin promotes the earlier onset of puberty in girls but not in boys. The effects of exposure to certain EDCs—mostly obesogenic chemicals that mimic the action of natural hormones—on the timing of puberty remain unclear; hence, further research on this topic is needed. Addressing and preventing obesity in children could potentially mitigate these alterations in pubertal timing. Full article

The issue of stray cats and dogs is a global concern with considerable implications for animal welfare and public health. This review aims to provide an updated and comprehensive analysis of non-surgical contraceptive methods tested in studies controlled in vivo in feline and canine females. Immunocontraception via vaccination against gonadotropin-releasing hormone (GnRH), the luteinizing hormone receptor, zona pellucida proteins, and sperm, or use of viral-vectored delivery, is yet developing. Hormonal treatment (progestins, androgens, or GnRH) analogs act directly to block the reproductive axis. However, it produced essential side effects. Analogs of kisspeptin, non-steroid anti-inflammatory drugs such as firocoxib, and delivery of cytotoxins to the pituitary have shown non-conclusive results. Additional methods have also been tested, such as intraovarian injection of necrosing compounds or intravaginal and intrauterine devices. At present, neither of these methods offers permanent sterility that can replace surgical sterilization techniques. To our knowledge, none are currently authorized by the Food and Drug Administration (FDA) or the European Medicines Agency (EMA) for contraceptive methods or sterilization of cats or dogs. Therefore, it is necessary to continue the development of a compound that warrants the sterility of cats and dogs. Full article

The kisspeptin/kisspeptin receptor (KISS1/KISS1R) system has emerged as a vital regulator of various physiological processes, including cancer progression, metabolic function, and reproduction. KISS1R, a member of the G protein-coupled receptor family, is crucial for regulating the hypothalamic/pituitary/gonadal axis. A growing number of KISS1R agonists are currently being investigated in clinical trials, whereas the number of antagonists remains limited. Most existing ligands are synthetic peptides, with only a few small-molecule compounds, such as musk ambrette, having been identified. In this article, we provide an overview of the KISS1/KISS1R system and its involvement in diseases such as reproductive disorders, cancer, diabetes, and cardiovascular disease. We also highlight the various technologies used to identify KISS1R ligands, including radioligand binding assays, calcium flux assays, IP1 formation assays, ERK phosphorylation assays, qRT-PCR, and AI-based virtual screening. Furthermore, we discuss the latest advances in identifying KISS1R agonists and antagonists, highlighting ongoing challenges and future directions in research. These insights lay the groundwork for future research aimed at leveraging this system for developing innovative therapeutic strategies across a range of medical conditions. Full article

Kisspeptins play a crucial role in the normal functioning of the reproductive axis in both humans and animals by stimulating the secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus. Recent studies have investigated the association of kisspeptins to infertility of diverse causes and the therapeutic potential of kisspeptins in infertility. Exogenous administration of kisspeptins appears to hold significant promise in restoring fertility, with ongoing studies in their application in ovarian stimulation protocols and as cryoprotectants during vitrification. This review provides a comprehensive analysis of the role of kisspeptins in reproductive physiology and their potential as therapeutic agents for infertility, highlighting their advantages over conventional treatments and their future prospects in clinical practice. Full article

Neurogenesis is considered the most robust form of plasticity in the adult brain. To better decipher this process, we evaluated the potential crosstalk of Kisspeptin and Endocannabinoid Systems (KPS and ECS, respectively) on hippocampal neurogenesis. Male adolescent rats were exposed to kisspeptin-10 (KP10) and the endocannabinoid anandamide (AEA) administered alone or in combination with the type 1 cannabinoid receptor (CB1R) antagonist SR141716A. The expression of Kiss1 and Kisspeptin receptor (Kiss1R) has been characterized for the first time in rat hippocampus together with the expression of the CB1R and the Transient Receptor Potential Vanilloid 1 ion channel receptor (TRPV1). Results show that both systems inhibit neurogenesis by reducing the extracellular signal-regulated kinase (ERK) signaling. Despite little differences in the expression of Kiss1R and CB1R, TRPV1 is enhanced by both KP10 and AEA treatments, suggesting TRPV1 as a common thread. KP10 administration reduces CB1R expression in the dentate gyrus, while AEA does not. KPS, unlike ECS, promotes the expression of estrogen receptor α (ER-α) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), also upregulating sirtuin 1 (SIRT1), brain-derived-neurotrophic factor (BDNF), and c-Jun. These findings suggest that the interaction between ECS and KPS could be involved in the fine-tuning of neurogenesis, highlighting a novel role for KPS. Full article

Maturation of follicles is the primary condition for the initiation of puberty, and excessive apoptosis of granulosa cells (GCs) will hinder the normal development of follicles in pigs. Signal Transducer and Activator of Transcription 4 (STAT4) plays an important role in cell proliferation and apoptosis. However, the mechanism of DNA methylation regulating STAT4 transcription and affecting follicle development in pigs remains unclear. To resolve this problem, we constructed a STAT4 overexpression vector and interference fragment to explore the effects of STAT4 on GC function and investigate the effects of changes in methylation status of the STAT4 promoter region on cell function and kisspeptin-1 (KISS1) expression, as well as the STAT4 effects on the development of the follicles of pigs and mice in vitro. We found that the expression of STAT4 decreased, while DNA methylation of the STAT4 promoter region increased with the growth of the follicles. After overexpression of STAT4, the apoptosis of GCs was increased but the proliferation, cell cycle and estrogen secretion of GCs were inhibited. When GCs were treated with DNA methyltransferase inhibitor (5-Aza-CdR), the methylation of the STAT4 promoter region decreased, resulting in a significant increase in the expression of STAT4. Consequently, the expression of KISS1 was inhibited. At the same time, the expressions of genes related to cell proliferation, cell cycle and estrogen secretion signaling pathways decreased, while the expressions of genes related to the apoptosis signaling pathway increased. After infection with the STAT4 lentiviral vector (LV-STAT4) in follicles of mice, the expression of STAT4 in ovaries of mice significantly increased, and the expression of KISS1 was significantly decreased. The capillaries on the surface of follicles were constricted, the age of puberty onset in mice was delayed while the levels of GnRH, LH, FSH and E2 in serum were decreased. In conclusion, we found that reduced methylation status of the STAT4 promoter region promoted the transcription of STAT4 and then inhibited the expression of KISS1, as well as promoted the apoptosis of GCs and ultimately inhibited the normal development of follicles in mammals. Full article

Vasomotor symptoms, such as hot flashes (HFs), commonly affect women during menopause, leading to a reduced quality of life. The current study evaluates the combined effect of active components Asparagus racemosus (AR) and Trigonella foenum-graecum (TFG) in a single oral formulation (IAT) for alleviating menopausal symptoms in ovariectomized rats. Following bilateral ovariectomy, the animals were randomly assigned to nine groups: (1) Control, (2) Ovariectomy (OVX), (3) OVX+TA1 (TA: Combination of Trigonella and Asparagus; TFG 30 mg/kg + AR 30 mg/kg), (4) OVX+TA2 (TFG 30 mg/kg + AR 15 mg/kg), (5) OVX+TA3 (TFG 15 mg/kg + AR 30 mg/kg), (6) OVX+TA4 (TFG 40 mg/kg + AR 30 mg/kg), (7) OVX+TA5 (TFG 30 mg/kg + AR 40 mg/kg), (8) OVX+IAT1 (IAT: Integrated Asparagus and Trigonella; TFG+AR integrated extract, 30 mg/kg), and (9) OVX+IAT2 (TFG+AR integrated extract, 60 mg/kg). On the 8th day of treatment, tail and skin temperatures were recorded every 30 min for 24 h. Ovariectomized rats exhibited menopausal symptoms, such as hormonal imbalances and elevated skin temperature. Administration of AR, TFG, and IAT significantly decreased serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and cortisol while increasing estradiol, progesterone, and dopamine (p < 0.0001), effectively alleviating hot flash-like symptoms. Additionally, they mitigated ovariectomy-induced oxidative stress by lowering malondialdehyde (MDA) levels and restoring antioxidant enzyme activity. Ovariectomized rats exhibited increased expression of a proto-oncogene (c-FOS), gonadotropin-releasing hormone (GnRH), Kisspeptin, Neurokinin B (NKB), and Transient receptor potential vanilloid 1 (TRPV1), along with reduced expressing brain-derived neurotrophic factor (BDNF) levels, which were reversed by treatment, especially with the IAT2 combination. The AR and TFG combination, particularly in IAT formulations, showed strong potential in alleviating menopausal symptoms in ovariectomized rats. These findings suggest that the combination of AR and TFG extracts could be a natural alternative for managing postmenopausal symptoms by restoring reproductive hormone levels, regulating lipid profiles, and enhancing antioxidant defense systems. Full article

Prader-Willi syndrome (PWS) is a rare genetic disorder. The main characteristics are muscular hypotonia, failure to thrive and feeding problems in infancy, which switch to hyperphagia in early childhood and continue into adulthood. Due to hyperphagia, the risk of developing morbid obesity is high without treatment. PWS is considered a hypothalamic disease, and within the hypothalamus the arcuate nucleus (AC) is of central importance for controlling metabolism, hunger, and satiety. The AC has been studied in several animal models as well as in humans, including PWS. The function of AC is regulated by several neuropeptides and proteins produced within the central nervous system such as oxytocin, orexin, tachykinins as well as the hypothalamic hormones, regulating the adeno-hypophyseal hormones, also acting as neurotransmitters. Additionally, there are many peripheral hormones among which insulin, leptin, adiponectin, ghrelin, and glucagon-like peptide (GLP-1) are the most important. High levels of adiponectin and ghrelin have consistently been reported in PWS, but dysregulation and deviating levels of many other factors and hormones have also been demonstrated in both individuals with PWS and in animal models. In this review, we focus on the role of AC and peptides and proteins produced within the central nervous system in the regulation of hunger and satiety in PWS. Full article

KNDy (kisspeptine, neurokinin B, dynorphin) neurons, located in the hypothalamus, play a crucial role in the development of vasomotor symptoms (VSM) in menopausal women. Estrogen withdrawal during menopause leads to the hyperactivation of kisspeptin and neurokinin B (NKB) secretion, contributing to the onset of these symptoms. The identification of NKB/neurokinin B receptor (NK3R) signaling as a key mechanism in menopausal hot flashes has driven the development of NK3R antagonists. These antagonists restore the disrupted balance in KNDy neuron activity caused by estrogen deficiency, thereby reducing the frequency and severity of VMS. In 2023, the FDA approved fezolinetant, the first selective NK3R antagonist, for the treatment of moderate to severe VMS associated with menopause. Additionally, elinzanetant, a dual neurokinin-1 and neurokinin-3 receptor antagonist, has demonstrated promising results. The approval application for elinzanetant was supported by positive findings from the OASIS 1, 2, and 3 Phase III clinical studies. The dual antagonism of NK-1 and NK-3 receptors enhances its efficacy by alleviating menopause-related sleep disturbances and modulating peripheral vasodilatation. In this regard, elinzanetant represents a promising non-hormonal treatment that targets the underlying causes of VMS through NK-1 and NK-3 receptor pathways. The development of neurokinin B antagonist for VMS treatment exemplifies the impact of advanced pharmacological research on gynecological endocrinology. Full article

Hypothyroidism causes ovarian dysfunction and infertility in women and animals and impairs the hypothalamic expression of kisspeptin (Kp). However, kisspeptin is also expressed in the genital system, and the lack of the Kp receptor (Kiss1r) in the uterus is linked to reduced implantation rates. This study investigated the impact of hypothyroidism on the uterine expression of Kp and Kiss1r in female rats throughout the estrous cycle and the associated changes in uterine activity modulators. Hypothyroidism was induced through daily administration of propylthiouracil (PTU) over a period of 14 days. Plasma levels of LH, E₂, and P₄, cyclicity, body and uterine weight, uterine histomorphometry, and the gene and/or protein expression of Kiss1, Kiss1r, estrogen receptor α (ERα), progesterone receptor (PR), and thyroid hormone receptor α (TRα) were assessed. Additionally, proliferative activity (CDC-47) and the gene expression of uterine receptivity mediators (SMO, WNT4, BMP2, HAND2, MUC1, and LIF) were evaluated. Hypothyroidism prolonged the diestrus and increased progesterone levels during this phase, while decreasing luteinizing hormone and estradiol on proestrus. In the uterus, hypothyroidism reduced Kp immunostaining on diestrus and KISS1R mRNA levels on proestrus. These changes were accompanied by reduced endometrial glands, reduced uterine proliferative activity, and reduced ERα gene and protein expression. Additionally, hypothyroidism led to reduced uterine gene expression of LIF, BMP2, WNT4, and HAND2. On the other hand, thyroid hypofunction increased uterine PR and TRα immunostaining, while it reduced PGR gene expression on diestrus. These findings demonstrate that hypothyroidism reduces the expression of Kiss1/Kiss1r system in the uterus, which is associated with disrupted uterine estrogen and progesterone signaling and reduced expression of uterine receptivity mediators across the rat estrous cycle. Full article

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder that affects women of reproductive age and is characterized by hyperandrogenism, ovulatory dysfunction and polycystic ovarian morphology. PCOS is often associated with hormonal imbalances, metabolic dysfunction and comorbid psychiatric disorders, including eating disorders (EDs). The review identifies key hormonal factors—serotonin, leptin, insulin, ghrelin, kisspeptin and cortisol—and their roles in the pathophysiology of PCOS and associated psychiatric symptoms. Serotonin deficiency, commonly seen in PCOS patients, is associated with mood and eating disorders. Fluctuations in leptin, the satiety hormone, affect hypothalamic–pituitary–ovarian axis function and ovarian follicle maturation, increasing the risk of infertility. Elevated levels of kisspeptin in PCOS patients contribute not only to hormonal dysregulation but also to increased susceptibility to eating disorders such as bulimia and binge eating, likely due to its influence on the limbic system and glucose metabolism. Hyperinsulinemia and insulin resistance further impair reproductive and metabolic health, while promoting eating disorders such as binge eating and bulimia. Ghrelin and cortisol also emerge as significant factors. The review emphasizes the bidirectional relationship between PCOS and eating disorders, in which hormonal imbalances perpetuate psychiatric conditions, creating a vicious cycle. A multidisciplinary approach including gynecologists, endocrinologists, psychiatrists and nutritionists is recommended to ensure complex treatment. Early identification of those at risk through targeted screening and personalized interventions is key. Future research should focus on discovering the underlying hormonal mechanisms to improve treatment strategies and quality of life for women with PCOS. Full article

This article presents a narrative review that explores the potential link between kisspeptin—a key regulator of the hypothalamic-pituitary-gonadal axis—and the pathogenesis of endometriosis. Kisspeptin plays a significant role in regulating reproductive functions by modulating the release of gonadotropin-releasing hormone (GnRH), which in turn stimulates the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Recent studies suggest that kisspeptin may also impact peripheral reproductive tissues and influence inflammatory processes involved in the development of endometriosis. Altered kisspeptin signaling has been associated with the abnormal hormonal environment observed in endometriosis, which affects menstrual cycles and ovarian function. Research indicates that women with endometriosis exhibit altered levels of kisspeptin and its receptor, KISS1R, in both eutopic and ectopic endometrial tissues, suggesting a role in disease progression, particularly in tissue invasion and lesion formation. Kisspeptin’s role in regulating matrix metalloproteinases (MMPs), enzymes essential for tissue remodeling, further supports its potential contribution to the pathophysiology of endometriosis. Moreover, kisspeptin-based therapeutic strategies are currently under investigation, with the aim of providing targeted treatments that reduce the side effects commonly associated with existing therapies. Despite promising findings, further research is needed to fully understand the mechanisms by which kisspeptin influences endometriosis. Full article