Search Results (60)

Plastics pollution is a critical global environmental issue, with growing concern over the increasing presence of nanoplastic particles. Plastics are major environmental pollutants that adversely affect human health, particularly when plastics from food sources enter the body and pose potential risks to reproductive health. Echinacea purpurea is an immunologically active medicinal plant containing phenolic acids and alkylamides. Nanoparticles present a promising approach to enhance the effectiveness, stability, and bioavailability of Echinacea purpurea ethanol extract (EE) active components. This study aimed to determine the protective effects of chitosan-silica-Echinacea purpurea nanoparticles (CSE) against reproductive injury induced by polystyrene nanoplastics (PS-NPs) in male rats. The results showed that CSE dose-dependently reduced oxidative damage and protected intestinal and reproductive health. Furthermore, CSE improved gut microbiota dysbiosis, preserved barrier integrity, and attenuated PS-NPs-induced inflammation in the colon, brain, and gonads. Inflammatory factors released from the gut can enter the bloodstream, cross the blood–brain barrier, and potentially modulate the hypothalamic–pituitary–gonadal (HPG) axis. CSE has also been shown to elevate neurotransmitter levels in the colon and brain, thereby repairing HPG axis dysregulation caused by PS-NPs through gut–brain communication and improving reproductive dysfunction. This study enhances our understanding of CSE in modulating the gut–brain and HPG axes under PS-NPs-induced damage. CSE demonstrates the capacity to provide protection and facilitate recovery by mitigating oxidative stress and inflammation, restoring gut microbiota balance, and preserving hormone levels in the context of PS-NPs-induced injury. Full article

Inhibin (INH) plays a key role in the regulation of the reproductive performance of geese. It inhibits follicle-stimulating hormone (FSH) secretion from the anterior pituitary gland to regulate spermatogenesis. Immunization against INH in male geese leads to the production of antibodies to neutralize the INH activity that enhances testicular function and gonadotropin production. The objectives of the present research were to elaborate on the effects of inhibin (INH) immunization on testicular histology, plasma LH, pituitary PRL mRNA, and hypothalamic VIP mRNA expressions in Yangzhou ganders. A total of 60 birds were selected and divided into control (CON) and INH-immunized (INH-immunized) groups, having 30 in each group. In this experiment, the ganders were immunized with INH three times, and birds in the CON group were inoculated with bovine serum albumin (BSA). The analyzed data revealed that immunization against inhibin had no significant effects on improving the plasma concentration of LH hormone; however, significant effects were observed on the germ cell line, hypothalamic VIP mRNA, and pituitary PRL mRNA expressions. It is concluded that INH (INH) immunization is an effective tool to improve reproductive efficiency in Yangzhou ganders; however, INH immunization may harm pituitary PRL mRNA and hypothalamic mRNA expressions and LH plasma concentration. Seasonality played a vital impact on the hypothalamus–pituitary–gonadal (HPG) axis. Full article

Gonadotropin-inhibitory hormone (GnIH) is well-established as a negative regulator of reproductive physiology and behavior across vertebrates, acting on the hypothalamic–pituitary–gonadal (HPG) axis; however, recent data have also demonstrated its involvement in the control of metabolic processes. GnIH neurons and fibers have been identified in hypothalamic regions associated with feeding behavior and energy homeostasis, with GnIH receptors being expressed throughout the hypothalamus. GnIH does not act alone in the hypothalamus, but rather interacts with the melanocortin system, as well as with other neuropeptides. GnIH and its receptors are also expressed in peripheral tissues involved in important metabolic functions. Therefore, the local action of GnIH in peripheral organs, including the pancreas, gastrointestinal tract, gonad, and adipose tissue, is also suggested. This review aims to provide a comprehensive summary of the emerging role of GnIH in metabolic regulation at both the central and peripheral levels. Full article

Nutritional intake is closely linked to gonadal development, although the mechanisms by which food intake affects gonadal development are not fully understood. Cholecystokinin (CCK) is a satiety neuropeptide derived from the hypothalamus, and the present study observed that hypothalamic CCK expression is significantly influenced by food intake, which is mediated through blood glucose levels. Interestingly, CCK and its receptors were observed to exhibit a high expression in the hypothalamus–pituitary–gonad (HPG) axis of grass carp (Ctenopharyngodon idellus), suggesting that CCK is potentially involved in regulating fish reproduction through the HPG axis. Further investigations revealed that CCK could significantly stimulate the expression of gonadotropin-releasing hormone-3 (GnRH3) in the hypothalamus. In addition, single-cell RNA sequencing showed that cckrb was highly enriched in pituitary follicle-stimulating hormone (FSH) cells. Further study confirmed that CCK can significantly induce FSH synthesis and secretion in primary cultured pituitary cells. Additionally, with primary cultured ovary cells as a model, the in vitro experiment demonstrated that CCK directly induces the expression of lhr, fshr, and cyp19a1a mRNA. This indicates that hypothalamic CCK may act as a nutrient sensor involved in regulating gonadal development in teleosts. Full article

The objectives of this investigation were to identify differentially expressed circular RNAs (circRNAs) in the hypothalamus of goats with high and low prolificacy and construct a circRNA-mRNA regulatory network to uncover key potential circRNAs that influence goat prolificacy. Transcriptome analysis was performed on hypothalamus samples from low-prolificacy (n = 5) and high-prolificacy (n = 6) Chuanzhong black goats to identify circRNAs that influence prolificacy in these goats. Differential expression analysis identified a total of 205 differentially expressed circRNAs, comprising 100 upregulated and 105 downregulated circRNAs in the high-prolificacy group compared with the low-prolificacy group. Enrichment analysis of these differentially expressed circRNAs indicated significant enrichment in Gene Ontology terms associated with mammalian oogenesis, negative regulation of neurotransmitter secretion, reproductive developmental processes, hormone-mediated signaling pathways, and negative regulation of hormone secretion. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis highlighted significant enrichment in the oxytocin signaling pathway, GnRH signaling pathway, and hormone-mediated oocyte maturation. The hypothalamus of low- and high-prolificacy goats contains circular RNAs (circRNAs), including chicirc_063269, chicirc_097731, chicirc_017440, chicirc_049641, chicirc_008429, chicirc_145057, chicirc_030156, chicirc_109497, chicirc_030156, chicirc_176754, and chicirc_193363. Chuanzhong black goats have the potential to influence prolificacy by modulating the release of serum hormones from the hypothalamus. A circRNA-miRNA regulatory network was constructed, which determined that miR-135a, miR-188-3p, miR-101-3p, and miR-128-3p may interact with differentially expressed circRNAs, thereby regulating reproductive capacity through the hypothalamic-pituitary-gonadal axis. The results of this study enhance our knowledge of the molecular mechanisms that regulate prolificacy in Chuanzhong black goats at the hypothalamic level. Full article

The current study focused on identifying the potential of irisin in mammalian reproduction. The established role of irisin, a proteolytic product of FNDC5, in adipose tissue browning, energy metabolism, and thermogenesis suggests its role in reproductive health, often disturbed by metabolic imbalances. Various studies on mice demonstrated irisin′s role in improving spermatogenesis, sperm count, and testosterone levels by influencing the hypothalamus–pituitary–gonadal axis. Moreover, in females, there is a fluctuation in levels of irisin during critical reproductive stages, including menstrual cycles, puberty, and pregnancy. Conditions like pregnancy complications, precocious puberty, and polycystic ovary syndrome (PCOS) are found to have an association with abnormal irisin levels. The potential role of irisin in endometrial receptivity and preventing endometritis is also discussed in this review. Overall, the influence of irisin on female and male reproduction is evident from various studies. However, further research is needed to elucidate irisin mechanism in reproduction and its potential as a therapeutic or diagnostic tool for reproductive dysfunctions and infertility. Full article

Sexual maturation in goats is a dynamic process regulated precisely by the hypothalamic–pituitary–gonadal axis and is essential for reproduction. The hypothalamus plays a crucial role in this process and is the control center of the reproductive activity. It is significant to study the molecular mechanisms in the hypothalamus regulating sexual maturation in goats. We analyzed the serum hormone profiles and hypothalamic mRNA expression profiles of female goats during sexual development (1 day old (neonatal, D1, n = 5), 2 months old (prepuberty, M2, n = 5), 4 months old (sexual maturity, M4, n = 5), and 6 months old (breeding period, M6, n = 5)). The results indicated that from D1 to M6, serum hormone levels, including FSH, LH, progesterone, estradiol, IGF1, and leptin, exhibited an initial increase followed by a decline, peaking at M4. Furthermore, we identified a total of 508 differentially expressed genes in the hypothalamus, with a total of four distinct expression patterns. Nuclear receptor subfamily 1, group D, member 1 (NR1D1), glucagon-like peptide 1 receptor (GLP1R), and gonadotropin-releasing hormone 1 (GnRH-1) may contribute to hormone secretion, energy metabolism, and signal transduction during goat sexual maturation via circadian rhythm regulation, ECM receptor interactions, neuroactive ligand–receptor interactions, and Wnt signaling pathways. This investigation offers novel insights into the molecular mechanisms governing the hypothalamic regulation of goat sexual maturation. Full article

Heat stress due to climate warming can significantly affect the synthesis of sex hormones in male adolescents, which can impair the ability of the hypothalamus to secrete gonadotropin-releasing hormone on the hypothalamic–pituitary–gonadal axis, which leads to a decrease in luteinizing hormone and follicle-stimulating hormone, which ultimately negatively affects spermatogenesis and testosterone synthesis. For optimal spermatogenesis, the testicular temperature should be 2–6 °C lower than body temperature. Heat stress directly affects the testes, damaging them and reducing testosterone synthesis. Additionally, chronic heat stress abnormally increases the level of aromatase in Leydig cells, which increases estradiol synthesis while decreasing testosterone, leading to an imbalance of sex hormones and spermatogenesis failure. Low levels of testosterone in male adolescents lead to delayed puberty and incomplete sexual maturation, negatively affect height growth and bone mineral density, and can lead to a decrease in lean body mass and an increase in fat mass. In order for male adolescents to acquire healthy reproductive capacity, it is recommended to provide sufficient nutrition and energy, avoid exposure to heat stress, and provide foods and supplements to prevent or repair testosterone reduction, germ cell damage, and sperm count reduction caused by heat stress so that they can enter a healthy adulthood. Full article

Sexual dimorphism refers to biological differences between males and females in the same species, including morphological, physiological, and behavioral characteristics. Steroid hormones are associated with changes in several brain regions, as well as the pathophysiology of aging, obesity, and neuropsychiatric diseases. The hypothalamus controls several physiological processes, including metabolism, reproduction, circadian rhythm, and body homeostasis. Refined communication between neurons and glial cells, particularly astrocytes, coordinates physiological and behavioral hypothalamic functions. Therefore, from previously published studies, this review aims to highlight sex-related differences in rodent hypothalamic astrocytes, since we believe that this brain region is essential for the understanding of dimorphic patterns that are influenced by steroid sex hormones. Thus, we review concepts of sexual dimorphism, the hypothalamic-pituitary-gonadal axis, the role of hormonal influence on hypothalamic astrocyte functions, neuroglial communication, as well as sexual dimorphism and neuropsychiatric disorders and glioprotective mechanisms associated with the hypothalamus. Full article

Nutritional status plays a vital role in regulating ovary activity. This regulation is mediated by the hypothalamus–pituitary–gonad axis and by effects exerted directly on the ovary. Therefore, to achieve the best reproductive performance, it is essential to know how the nutritional status affects the secretion of GnRH, gonadotrophins, and sex steroid hormones. Adequate body reserves and energy balance are critical for optimal reproductive performance in sheep and goats. However, over- or under-conditioned animals experience issues like extended anestrus, irregular ovarian cycles, and reduced conception. Body condition scoring allows for the evaluation of the relationships between adiposity, nutritional status, and fertility. Acute feed deficits briefly stimulate processes, but chronic restrictions suppress pulsatile LH release, disrupting ovarian function. The process of follicle development is a very complex one which involves intricate interactions between the pituitary gonadotrophins and metabolic hormones as well as between the locally produced factors by the ovarian somatic and germ cells including the IGF system and the TGF-β superfamily members. Genotype and nutrition are factors that have an impact on follicular development, and seasonal factors are also involved. This review will give a brief overview on how the body condition can be evaluated and the effects of nutrition on the hypothalamus–pituitary–gonad axis and ovarian activity, which are responsible for reproductive regulation. This paper presents a clear and reasonable summary of the pathway that runs from the nutritional status of small ruminants to ovarian activity through the hypothalamic–pituitary–gonadal axis. This review summarizes methods for body condition evaluation in small ruminants and evidence regarding acute versus prolonged nutritional impacts on the hypothalamic–pituitary–gonadal axis and ovarian activity controlling reproduction. Full article

The present study investigated the reproductive and developmental effects of sex-specific chronic exposure to dietary arsenic in zebrafish. Adult zebrafish (Danio rerio) were exposed to environmentally realistic doses of arsenic via diet [0 (control; no added arsenic), 30 (low), 60 (medium), and 100 (high) μg/g dry weight, as arsenite] for 90 days. Following exposure, arsenic-exposed females from each dietary treatment were mated with control males, and similarly, arsenic-exposed males from each dietary treatment were mated with control females. In females, arsenic exposure resulted in a dose-dependent decrease in reproductive performance (fecundity, fertilization success, and hatching success). Moreover, a dose-dependent increase in developmental toxicity (larval deformities and larval mortality) was observed with maternal exposure to arsenic. In contrast, in males, arsenic exposure also induced similar reproductive and developmental toxicity; however, the adverse effects were mainly evident only in the medium and high dietary arsenic treatment groups. We also examined the sex-specific effects of dietary arsenic exposure on the expression of genes that regulate the hypothalamus–pituitary–gonadal–liver (HPG-L) axis in fish. The gene expression results indicated the downregulation of HPG-L axis genes in females irrespective of the arsenic treatment dose; however, the reduced expression of HPG-L axis genes in males was recorded only in the medium and high arsenic treatment groups. These observations suggest that chronic arsenic exposure in either females or males causes reproductive and developmental toxicity in zebrafish. However, these toxic effects are markedly higher in females than in males. Our results also suggest that arsenic can act as an endocrine disruptor and mediate reproductive and developmental toxicity by disrupting the HPG-L axis in zebrafish. Full article

The rising incidence of obesity has coincided with rising levels of poor reproductive outcomes. The molecular basis for the association of infertility in obese males is now being explained through various mechanisms. Insulin resistance, hyperglycemia, and changes in serum and gonadal concentrations of adipokines, like leptin, adiponectin, resistin, and ghrelin have been implicated as causes of male infertility in obese males. The effects of obesity and hypogonadism form a vicious cycle whereby dysregulation of the hypothalamic–pituitary–testicular axis—due to the effect of the release of multiple mediators, thus decreasing GnRH release from the hypothalamus—causes decreases in LH and FSH levels. This leads to lower levels of testosterone, which further increases adiposity because of increased lipogenesis. Cytokines such as TNF-α and interleukins, sirtuins, and other inflammatory mediators like reactive oxygen species are known to affect fertility in obese male adults. There is evidence that parental obesity can be transferred through subsequent generations to offspring through epigenetic marks. Thus, negative expressions like obesity and infertility have been linked to epigenetic marks being altered in previous generations. The interesting aspect is that these epigenetic expressions can be reverted by removing the triggering factors. These positive modifications are also transmitted to subsequent generations. Full article

Steroid hormone production via the adrenal cortex, gonads, and placenta (so-called glandular steroidogenesis) is responsible for the endocrine control of the body’s homeostasis and is organized by a feedback regulatory mechanism based on the hypothalamus–pituitary–steroidogenic gland axis. On the other hand, recently discovered extraglandular steroidogenesis occurring locally in different tissues is instead linked to paracrine or autocrine signaling, and it is independent of the control by the hypothalamus and pituitary glands. Bone cells, such as bone-forming osteoblasts, osteoblast-derived osteocytes, and bone-resorbing osteoclasts, respond to steroid hormones produced by both glandular and extraglandular steroidogenesis. Recently, new techniques to identify steroid hormones, as well as synthetic steroids and steroidogenesis inhibitors, have been introduced, which greatly empowered steroid hormone research. Based on recent literature and new advances in the field, here we review the local role of steroid hormones in regulating bone homeostasis and skeletal lesion formation. The novel idea of extraglandular steroidogenesis occurring within the skeletal system raises the possibility of the development of new therapies for the treatment of bone diseases. Full article

Cadmium (Cd) is a non-essential element with sub-lethal effects even at low concentrations. The persistent nature of Cd and its tendency to bioaccumulate eventually create harmful effects on water biota, including fish. Cd affects various aspects of hormonal action in fish since it bioaccumulates in the endocrine system and hinders the synthesis, secretion, and metabolic activity of hormones, causing severe damage along the hypothalamus–pituitary–gonadal axis. Linking reproductive and developmental impairments in fish with ecologically relevant concentrations of individual metals can be challenging due to the complexity of aquatic ecosystems. This review deliberated the significant and novel trends of toxicological difficulties and approaches, including elucidating environmental sources’ bioavailability and Cd-induced toxic effects in freshwater fish. Both acute and chronic exposure to Cd can cause a range of adverse effects, such as growth inhibition, impaired reproductive capacity, endocrine disruption, and developmental abnormalities in freshwater fish, as evidenced by the present review. These investigations support the concept of Cd as a naturally available pollutant that causes irreversible damage in fish. These findings will help to understand the etiology of environmental circumstances that pose substantial dangers to fish health and are also crucial for preventing and treating exposure-related reproductive disturbances in freshwater fish due to environmental pollution. Full article

GNAQ, a member of the alpha subunit encoding the q-like G protein, is a critical gene in cell signaling, and multiple studies have shown that upregulation of GNAQ gene expression ultimately inhibits the proliferation of gonadotropin-releasing hormone (GnRH) neurons and GnRH secretion, and ultimately affects mammalian reproduction. Photoperiod is a key inducer which plays an important role in gene expression regulation by affecting epigenetic modification. However, fewer studies have confirmed how photoperiod induces epigenetic modifications of the GNAQ gene. In this study, we examined the expression and epigenetic changes of GNAQ in the hypothalamus in ovariectomized and estradiol-treated (OVX+E₂) sheep under three photoperiod treatments (short photoperiod treatment for 42 days, SP42; long photoperiod treatment for 42 days, LP42; 42 days of short photoperiod followed by 42 days of long photoperiod, SP-LP42). The results showed that the expression of GNAQ was significantly higher in SP-LP42 than in SP42 and LP42 (p < 0.05). Whole genome methylation sequencing (WGBS) results showed that there are multiple differentially methylated regions (DMRs) and loci between different groups of GNAQ. Among them, the DNA methylation level of DMRs at the CpG1 locus in SP42 was significantly higher than that of SP-LP42 (p < 0.01). Subsequently, we confirmed that the core promoter region of the GNAQ gene was located with 1100 to 1500 bp upstream, and the DNA methylation level of all eight CpG sites in SP42 was significantly higher than those in LP42 (p < 0.01), and significantly higher than those in SP-LP42 (p < 0.01), except site 2 and site 4 in the first sequencing fragment (p < 0.05) in the core promoter region. The expression of acetylated GNAQ histone H3 was significantly higher than that of the control group under three different photoperiods (p < 0.01); the acetylation level of sheep hypothalamic GNAQ genomic protein H3 was significantly lower under SP42 than under SP-LP42 (p < 0.05). This suggests that acetylated histone H3 binds to the core promoter region of the GNAQ gene, implying that GNAQ is epigenetically regulated by photoperiod through histone acetylation. In summary, the results suggest that photoperiod can induce DNA methylation in the core promoter region and histone acetylation in the promoter region of the GNAQ gene, and hypothesize that the two may be key factors in regulating the differential expression of GNAQ under different photoperiods, thus regulating the hypothalamus–pituitary–gonadal axis (HPGA) through the seasonal estrus in sheep. The results of this study will provide some new information to understand the function of epigenetic modifications in reproduction in sheep. Full article