Molecular regulation of hypothalamus-pituitary-gonads axis in males

From pituitary cells to prostate gland in health and disease: direct and indirect endocrine connections

The prostate gland is an endocrine-sensitive organ responding to multiple stimuli. Its development and function are regulated by multiple hormones (i.e. steroids such as androgens, estrogens and glucocorticoids) but also by other key hormonal systems such as those comprised by insulin-like growth factor 1 and insulin, which are sourced by different tissues [e.g. testicles/adrenal-gland/adipose-tissue/liver/pancreas, etc.). Particularly important for the endocrine control of prostatic pathophysiology and anatomy are hormones produced and/or secreted by different cell types of the pituitary gland [growth-hormone, luteinizing-hormone, follicle-stimulating hormone, and prolactin, oxytocin, arginine-vasopressin and melanocyte-stimulating hormone], which affect prostate gland function either directly or indirectly under physiological and pathophysiological conditions [e.g. metabolic dysregulation (e.g. obesity), and prostate transformations (e.g. prostate cancer)]. This review summarizes the impact of all pituitary hormone types on prostate gland under these diverse conditions including in vivo and in vitro studies.

Impact of Obesity on Pubertal Timing and Male Fertility

Childhood obesity has profound effects on puberty in boys and girls, altering its timing, progression, and associated hormonal changes. Also, later male fertility could be impaired by childhood and pubertal obesity in light of the impact of inflammatory markers on semen quality. The aim of this narrative review is to explore the intricate relationship between childhood obesity and its impact on pubertal development and fertility, with a specific focus on boys. Such a relationship between obesity and pubertal timing in males is highly influenced by metabolic, hormonal, genetic, epigenetic, and environmental factors. While many studies suggest that obesity accelerates pubertal onset in boys, some studies do not confirm these findings, especially in cases of severe obesity. In fact, delayed puberty has also been reported in certain instances. Obesity influences fertility through different central and peripheral processes, including an altered endocrine milieu, inflammatory environment, and epigenetic modifications that alter semen quality and vitality, leading to subfertility or infertility. The early identification and management of potential issues associated with obesity are crucial for ensuring optimal reproductive health in adulthood. Further research is essential to clarify these associations and to develop targeted interventions aimed at preventing the negative health outcomes associated with obesity-related disruptions in puberty and fertility.

Clomiphene Citrate Treatment as an Alternative Therapeutic Approach for Male Hypogonadism: Mechanisms and Clinical Implications

Male hypogonadism, which is characterized by low testosterone levels, has a significant impact on male sexual function, overall health, and fertility. Testosterone replacement therapy (TRT) is the conventional treatment for this condition, but it has potential adverse effects and is not suitable for men seeking to conceive. Testosterone plays an essential role in male sexual function, metabolism, mood, and overall well-being. Clomiphene citrate, a drug originally developed for female infertility, has recently gained attention as an off-label treatment for male hypogonadism. By blocking the negative feedback of estrogen on the hypothalamus and pituitary glands, clomiphene stimulates gonadotropin secretion, leading to increased endogenous testosterone production, which, in turn, improves sperm parameters and fertility and alleviates the symptoms of hypogonadism. Regarding the safety profile of clomiphene compared with TRT, clomiphene appears to confer a lower risk than TRT, which is associated with adverse effects such as polycythemia. Furthermore, combination therapy with clomiphene and anastrozole or human chorionic gonadotropin has been investigated as a potential approach to enhancing the effectiveness of treatments for improving hypogonadism symptoms. In conclusion, clomiphene citrate may offer a promising alternative to TRT for men with hypogonadism, particularly those desiring fertility preservations. However, its long-term efficacy and safety remain inadequately understood. Future research should focus on exploring the benefits of combination therapies and personalized treatment strategies based on individual patient characteristics.

Relative Energy Deficiency in Sport (REDs): Endocrine Manifestations, Pathophysiology and Treatments

Research on lean, energy-deficient athletic and military cohorts has broadened the concept of the Female Athlete Triad into the Relative Energy Deficiency in Sport (REDs) syndrome. REDs represents a spectrum of abnormalities induced by low energy availability (LEA), which serves as the underlying cause of all symptoms described within the REDs concept, affecting exercising populations of either biological sex. Both short- and long-term LEA, in conjunction with other moderating factors, may produce a multitude of maladaptive changes that impair various physiological systems and adversely affect health, well-being, and sport performance. Consequently, the comprehensive definition of REDs encompasses a broad spectrum of physiological sequelae and adverse clinical outcomes related to LEA, such as neuroendocrine, bone, immune, and hematological effects, ultimately resulting in compromised health and performance. In this review, we discuss the pathophysiology of REDs and associated disorders. We briefly examine current treatment recommendations for REDs, primarily focusing on nonpharmacological, behavioral, and lifestyle modifications that target its underlying cause-energy deficit. We also discuss treatment approaches aimed at managing symptoms, such as menstrual dysfunction and bone stress injuries, and explore potential novel treatments that target the underlying physiology, emphasizing the roles of leptin and the activin-follistatin-inhibin axis, the roles of which remain to be fully elucidated, in the pathophysiology and management of REDs. In the near future, novel therapies leveraging our emerging understanding of molecules and physiological axes underlying energy availability or lack thereof may restore LEA-related abnormalities, thus preventing and/or treating REDs-related health complications, such as stress fractures, and improving performance.

Hormonal and Allosteric Regulation of the Luteinizing Hormone/Chorionic Gonadotropin Receptor

Luteinizing hormone (LH) and human chorionic gonadotropin (CG), like follicle-stimulating hormone, are the most important regulators of the reproductive system. They exert their effect on the cell through the LH/CG receptor (LHCGR), which belongs to the family of G protein-coupled receptors. Binding to gonadotropin induces the interaction of LHCGR with various types of heterotrimeric G proteins (Gs, Gq/11, Gi) and β-arrestins, which leads to stimulation (Gs) or inhibition (Gi) of cyclic adenosine monophosphate-dependent cascades, activation of the phospholipase pathway (Gq/11), and also to the formation of signalosomes that mediate the stimulation of mitogen-activated protein kinases (β-arrestins). The efficiency and selectivity of activation of intracellular cascades by different gonadotropins varies, which is due to differences in their interaction with the ligand-binding site of LHCGR. Gonadotropin signaling largely depends on the status of N- and O-glycosylation of LH and CG, on the formation of homo- and heterodimeric receptor complexes, on the cell-specific microenvironment of LHCGR and the presence of autoantibodies to it, and allosteric mechanisms are important in the implementation of these influences, which is due to the multiplicity of allosteric sites in different loci of the LHCGR. The development of low-molecular-weight allosteric regulators of LHCGR with different profiles of pharmacological activity, which can be used in medicine for the correction of reproductive disorders and in assisted reproductive technologies, is promising. These and other issues regarding the hormonal and allosteric regulation of LHCGR are summarized and discussed in this review.

Long-term carbaryl exposure leads to behavioral abnormalities and reproductive toxicity in male marine medaka through apoptosis-mediated HPA and HPG axes dysregulation

Carbaryl is a widely used carbamate pesticide that has been detected in the marine environment, but its effects on marine fish are still unknown. This study was aimed to investigate the effects of long-term exposure of carbaryl on male marine medaka. For this purpose, we set up five exposure concentration groups of 0, 0.1, 1, 10, and 100 µg/L for 180 days. On the one hand, we observed increased aggression and decreased ability to avoid predators in males after exposure, which was affected by the levels of HPA-axis hormones, especially decreased cortisol level. On the other hand, after exposure, HPG axis hormone levels and gene transcription levels were disturbed. Males exhibited a decreased gonadosomatic index and a notable reduction in mature sperm proportion and the F1 generation displayed a significant increase in malformation rate. Additionally, the number of apoptotic cells and the transcription level of apoptosis-related genes in the brains of male marine medaka substantially increased after exposure. Apoptosis of brain cells may be responsible for the disturbance of HPA and HPG axes, consequently leading to behavioral and reproductive abnormalities. These findings provide novel insights into evaluating the toxic effects of carbaryl on male marine medaka and emphasizing the criticality of exploring the potential environmental risks posed by carbaryl in the marine environment, thus providing toxicity value basis for further strengthening marine environmental monitoring and the protection of biological resources.

Mini-Puberty, Physiological and Disordered: Consequences, and Potential for Therapeutic Replacement

There are 3 physiological waves of central hypothalamic-pituitary-gonadal (HPG) axis activity over the lifetime. The first occurs during fetal life, the second-termed "mini-puberty"-in the first months after birth, and the third at puberty. After adolescence, the axis remains active all through adulthood. Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disorder characterized by a deficiency in hypothalamic gonadotropin-releasing hormone (GnRH) secretion or action. In cases of severe CHH, all 3 waves of GnRH pulsatility are absent. The absence of fetal HPG axis activation manifests in around 50% of male newborns with micropenis and/or undescended testes (cryptorchidism). In these boys, the lack of the mini-puberty phase accentuates testicular immaturity. This is characterized by a low number of Sertoli cells, which are important for future reproductive capacity. Thus, absent mini-puberty will have detrimental effects on later fertility in these males. The diagnosis of CHH is often missed in infants, and even if recognized, there is no consensus on optimal therapeutic management. Here we review physiological mini-puberty and consequences of central HPG axis disorders; provide a diagnostic approach to allow for early identification of these conditions; and review current treatment options for replacement of mini-puberty in male infants with CHH. There is evidence from small case series that replacement with gonadotropins to mimic "mini-puberty" in males could have beneficial outcomes not only regarding testis descent, but also normalization of testis and penile sizes. Moreover, such therapeutic replacement regimens in disordered mini-puberty could address both reproductive and nonreproductive implications.

Fathers and sons, mothers and daughters: Sex-specific genetic architecture for fetal testosterone in a wild mammal

Testosterone plays a critical role in mediating fitness-related traits in many species. Although it is highly responsive to environmental and social conditions, evidence from several species show a heritable component to its individual variation. Despite the known effects that in utero testosterone exposure have on adult fitness, the heritable component of individual testosterone variation in fetuses is mostly unexplored. Furthermore, testosterone has sex-differential effects on fetal development, i.e., a specific level may be beneficial for male fetuses but detrimental for females, producing sexual conflict. Such sexual conflict may be resolved by the evolution of a sex-specific genetic architecture of the trait. Here, we quantified fetal testosterone levels in a wild species, free-ranging nutrias (Myocastor coypus) using hair-testing and estimated testosterone heritability between parent and offspring from the same and opposite sex. We found that in utero accumulated hair testosterone levels were heritable between parents and offspring of the same sex. Moreover, there was a low additive genetic covariance between the sexes, and a low cross-sex genetic correlation, suggesting a potential for sex-specific trait evolution, expressed early on, in utero.

The dissection of a despotic society: exploration, dominance and hormonal traits

Naked mole-rats (Heterocephalus glaber) live in large colonies with one breeding female (queen), one to three breeding males (BMs) and the remainder are non-reproductive subordinates. The animals have a linear dominance rank with the breeders at the top of the hierarchy. We investigated how dominance rank in naked mole-rats differs with exploration (the propensity to explore a novel environment) and related endocrine markers. Exploration behaviour, faecal progestagen metabolite (fPM), faecal glucocorticoid metabolite (fGCM), faecal androgen metabolite (fAM) and plasma prolactin concentrations were quantified in breeding, high-, middle- and low-ranked females and males from five naked mole-rat colonies. There were no significant differences between the dominance rank and exploration behaviour. Interestingly, the queens and high-ranking females had higher fGCM and fAM concentrations compared with middle- and low-ranked females. The queens had significantly higher fPM concentrations than all other ranked females, since they are responsible for procreation. In the males, the BMs had higher fGCM concentrations compared with high- and low-ranked males. In addition, BMs and middle-ranking males had overall higher prolactin levels than all other ranked males, which could be linked to cooperative care. Overall, the results suggest that physiological reproductive suppression is linked to high dominance rank.

Unraveling Hypothalamus-Pituitary dysregulation: Hypergonadotropism in F1 progeny due to prenatal exposure to hexavalent chromium

The endocrine disruptor hexavalent chromium [Cr(VI)] is a proven reproductive toxicant. We recently demonstrated that prenatal Cr(VI) exposure causes testicular resistance to gonadotropins, resulting in hypergonadotropic hypoandrogenism in F1 rats. However, the mechanism driving hypergonadotropism in F1 rats exposed to Cr(VI) prenatally remains an enigma. Therefore, we hypothesized that 'Prenatal Cr(VI) exposure may disrupt steroid hormones-mediated negative feedback regulation of the hypothalamic GnRH, and its receptor in the pituitary of F1 rats, leading to hypergonadotropism.' We administered potassium dichromate (50, 100, or 200 mg/L) to pregnant rats through drinking water between days 9 and 14, and their male F1 offspring were euthanized at 60 days of age. Prenatal Cr(VI) exposure in F1 rats resulted in the accumulation of Cr in the hypothalamus and pituitary. Western blot detected decreased hypothalamic GnRH, Kisspeptin1, and its receptor GPR54, along with diminished ERα, AR, aromatase, and 5α reductase, and GnRH regulatory transcription factors Pit-1 and GATA-4 proteins. Immunohistochemical studies revealed increased immunopositivity of GnRH receptor, AR, 5α reductase, ERα, ERβ, and aromatase proteins in the pituitary, whereas decreased Kisspeptin1, GPR54, and inhibin β. Our findings imply that Cr(VI) exposure during the prenatal period disrupts the hypothalamic Kisspeptin-GPR54-Pit-1/GATA4-GnRH network, boosting the pituitary GnRH receptor. We conclude that prenatal exposure to Cr(VI) alters GnRH expression in the hypothalamus and its receptor in the pituitary of F1 progeny through interfering with the negative feedback effect of androgens and estrogens.

Comprehensive transcriptomic analysis revealing the regulatory dynamics and networks of the pituitary-testis axis in sheep across developmental stages

Spermatogenesis is a complex process intricately regulated by the hypothalamic-pituitary-testis (HPT) axis. However, research on the regulatory factors governing the HPT axis remains limited. This study addresses this gap by conducting a comprehensive analysis of transcriptomes from the pituitary and testis tissues across various developmental stages, encompassing embryonic day (E120), neonatal period (P0), pre-puberty (P90), and post-puberty day (P270). Utilizing edgeR and WGCNA, we identified stage-specific genes in both the pituitary and testis throughout the four developmental stages. Notably, 380, 242, 34, and 479 stage-specific genes were identified in the pituitary, while 886, 297, 201, and 3,678 genes were identified in the testis. Subsequent analyses unveiled associations between these stage-specific genes and crucial pathways such as the cAMP signaling pathway, GnRH secretion, and male gamete generation. Furthermore, leveraging single-cell data from the pituitary and testis, we identified some signaling pathways involving BMP, HGF, IGF, and TGF-β, highlighting mutual regulation between the pituitary and testis at different developmental stages. This study sheds light on the pivotal role of the pituitary-testis axis in the reproductive process of sheep across four distinct developmental stages. Additionally, it delves into the intricate regulatory networks governing reproduction, offering novel insights into the dynamics of the pituitary-testis axis within the reproductive system.

Epigenetics of inflammation in hypothalamus pituitary gonadal and neuroendocrine disorders

The hormone producing hypothalamus, pituitary and gonadal are arranged in hierarchy to form the hypothalamic-pituitary-gonadal axis (HPG axis). The axis is neuroendocrine in nature and releases hormones in response to the inputs from nervous systems. The axis maintains homeostasis and ensures smooth body functions, particularly those related to growth and reproduction. A deregulated HPG axis, such as observed under inflammation and other conditions, is therefore associated with several disorders such as polycystic ovary syndrome, functional hypothalamic amenorrhea etc. Several factors, both genetic as well as environmental, in addition to aging, obesity etc. affect HPG axis with resulting effects on puberty, sexual maturation and reproductive health. More research is now indicative of a role of epigenetics in mediating these HPG-affecting factors. Hypothalamus-secreted gonadotropin-releasing hormone is important for eventual release of sex hormones and it is subjected to several neuronal and epigenetic regulations. Gene promoter methylation as well as histone methylations and acetylations form the backbone of epigenetic regulation of HPG-axis, as the incoming reports suggest. Epigenetic events also mediate several feedback mechanisms within HPG axis and between HPG axis and the central nervous system. In addition, data is emerging for a role of non-coding RNAs, particularly the miRNAs, in regulation and normal functioning of HPG axis. Thus, the epigenetic interactions need better understanding to understand the functioning and regulation of HPG axis.

Relationship between semen parameters, serum InhB, and INSL-3 levels, and the degree of varicocele

BACKGROUND

Varicocele is an abnormal expansion of the pampininias venous plexus in the scrotum, resulting in impaired sperm production and reduced sperm quality. The exact pathophysiological mechanism leading to varicocele-related infertility has not been fully elucidated. Although treatable, varicocele may lead to male infertility.

OBJECTIVE

To investigate the relationship between semen parameters, serum InhB and INSL-3 levels, and the degree of varicocele in male patients.

METHODS

Serum InhB and INSL-3 were detected. To evaluate the relationship between semen parameters and serum InhB and INSL-3 levels. To evaluate the value of semen parameters and serum InhB and INSL-3 levels in distinguishing disease severity in patients with varicocele.

RESULTS

Serum INSL-3 in patients with varicocele decreased with the severity of the disease. Serum INSL-3 was positively correlated with total sperm count and frequency of normal sperm morphology. There was a weak correlation between serum InhB and semen volume, concentration, and total sperm. Patients with different disease severity were similar within the groups, with partial overlap or similarity between varicocele Grade I and Grade II, and significant differences between Grade III and Grade I and II. Semen volume, concentration, total sperm, normal sperm morphology, and serum InhB and INSL-3 levels could distinguish the degree of varicocele.

CONCLUSION

Semen parameters and the combination of serum InhB and INSL-3 levels in patients with varicocele are closely related to the severity of the disease. Serum INSL-3 is expected to be a potential biomarker for early clinical intervention.

Effects of sub-chronic exposure to microcystin-LR on the endocrine system of male rats

Microcystins (MCs) can cause reproductive and developmental toxicity and disrupt endocrine homeostasis in mammals. In the present study, male, Sprague-Dawley (SD) rats were administrated 3 or 30 μg MC-LR/kg, body mass (bm) per day via intraperitoneal (i.p.) injections for 6 weeks. Effects of MC-LR on histology, hormone concentrations, gene transcriptional profiles and protein expressions along the hypothalamic-pituitary-adrenal (HPA), -gonad (HPG) and -thyroid (HPT) axes were assessed. Sub-chronic administration with MC-LR caused histological damage to hypothalamus, pituitary, adrenal, testes and thyroid and affected relative masses of pituitary, adrenal and testes. The HPA axis was activated and serum concentrations of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were significantly augmented. Along the HPG axis, serum concentrations of gonadotropin-releasing hormone (GnRH) and dihydrotestosterone (DHT) were diminished, while concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T) and estradiol (E2) were augmented. For the HPT axis, only concentrations of free tetra-iodothyronine (fT4) were significantly diminished, while concentrations of thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH) or free tri-iodothyronine (fT3) were not significantly changed. Also, several genes and proteins related to synthesis of steroid hormones were significantly altered. Findings of the present study illustrate that MC-LR can cause endocrine-disrupting effects through the disruption of synthesis and secretion of hormones along the HPA, HPG and HPT axes and negative feedback regulation. Also, there could be crosstalk among HPA, HPG and HPT axes. These findings elucidate mechanisms of endocrine-disrupting effects of MCs.

Involvement of estrogen receptor alpha (ERα) and impairment of steroidogenesis after exposure to tris(2,3-dibromopropyl) isocyanurate (TBC) in mouse spermatogenic (GC-1 spg) cells in vitro

Good-quality reproductive cells are essential for reproduction. Endocrine disruptors are widely available in the environment and are known to have an adverse effect on spermatogenesis and steroidogenesis. One of them is tris(2,3-dibromopropyl) isocyanurate (TBC), i.e. one of the novel brominated flame retardants (NBFR). TBC is a widely distributed ingredient used in the production of flame retardants. Currently, it is known to affect the hormonal system, but the exact mechanism of its action is unknown. Therefore, the aim of the study was to determine whether TBC alone and in cotreatment with BHPI (estrogen receptor alpha antagonist) has an impact on the expression of nuclear receptors involved in the formation of steroid hormones, proteins, and enzymes responsible for steroidogenesis and the levels of steroid hormones (E2, P4, and T) in the GC-1 spg cell line as a mouse model of spermatogenic cells in vitro. Our results indicate that ERα is involved in the mechanism of TBC action, while no activation of PPARγ, AhR, and IGF-1R was observed. In addition, a decrease in the levels of most of the analyzed proteins and enzymes involved in steroid conversion was observed. Only Cyp19a1 was upregulated after TBC, BHPI, and TBC with BHPI cotreatment. In all the analyzed groups, a significant decrease in P4 and a subtle decrease in T and E2 were observed in the production and secretion of the hormones to the culture medium, compared to the control. The obtained results confirm the involvement of TBC in the dysregulation of steroid biosynthesis, which may affect male fertility.

Non-Invasive Quantification of Faecal and Urine Reproductive Hormone Metabolites in the Naked Mole-Rat (Heterocephalus glaber)

The naked mole-rat (Heterocephalus glaber) occurs in colonies with a distinct dominance hierarchy, including one dominant, breeding female (the queen), 1-3 breeding males, and non-reproductive subordinates of both sexes that are reproductively suppressed while in the colony. To non-invasively evaluate reproductive capacity in the species, we first had to examine the suitability of enzyme immunoassays (EIAs) for determining progestogen and androgen metabolite concentrations in the naked mole-rat, using urine and faeces. A saline control and gonadotrophin-releasing hormone (GnRH) were administered to twelve (six males and six females) naked mole-rats which were previously identified as dispersers and housed singly. The results revealed that urine is possibly not an ideal matrix for progestogen and androgen metabolite quantification in naked mole-rats as no signal was detected in the matrix post GnRH administration. A 5α-Progesterone EIA and an Epiandrosterone EIA were identified as suitable for quantifying faecal progesterone metabolites (fPMs) and faecal androgen metabolites (fAMs) in males and females, respectively. The results suggest that there are individual variations in baseline fPM and fAM concentrations, and only two out of six females and no males exhibited an increase in fPM concentrations greater than 100% (-20% SD) post GnRH administration. Conversely, only four out of six females and three out of six males had an increase in fAM concentrations greater than 100% (-20% SD) following GnRH administration. These results imply that some naked mole-rat individuals have a reduced reproductive capacity even when they are separated from the queen.

Effects of Varicocele Surgical Repair on Serum Hormone and Inhibin B Levels for Patients With Varicocele: A Systematic Review and Meta-Analysis

Varicocele surgical repair can improve the function of the testis for patients with varicocele. We carried out a systematic review and meta-analysis to assess the effects of varicocele surgical repair on serum hormones and inhibin B levels in patients with varicocele. A literature search was performed in August 2022, and no language or geographic region restrictions were applied. The search included the following databases: PubMed, Embase, and Medline. A literature review was performed to identify all published clinical trials assessing serum hormone and inhibin B levels before and after varicocele surgical repair. The reference lists of retrieved studies were also investigated. A systematic review and meta-analysis were conducted. Eight articles were selected from 162 articles, including 452 patients. The combined analysis showed that after surgical treatment, mean serum testosterone, inhibin B, and sperm concentration levels increased compared with preoperative levels (p < .05). After surgical treatment, mean serum follicle-stimulating hormon (FSH), and Luteinizing hormone (LH) levels decreased compared with preoperative levels (p < .05). This meta-analysis demonstrates that varicocele surgical repair can improve testicular function, increase serum testosterone, and inhibin B levels and decrease serum FSH and LH levels in patients with varicocele. This might be related to the improvement of infertility. A large-scale multicenter randomized controlled study is needed for further confirmation.

Identification and characterization of gonadotropin-releasing hormone (GnRH) in Zhikong scallop Chlamys farreri during gonadal development

Gonadotropin-releasing hormone (GnRH) controls synthesis of sex steroid hormones through hypothalamic-pituitary-gonadal (HPG) axis in vertebrates. But in mollusks, research on neuroendocrine control of gonadal function, such as the function of GnRH during gonadal development is limited. In this study, we investigated the morphology and structure of the nerve ganglia of Zhikong scallop Chlamys farreri by physiological and histological observations. We also cloned the ORF and studied the expression patterns of GnRH in the scallop. Tissue expression analysis showed that GnRH was highly expressed in parietovisceral ganglion (PVG). The in situ hybridization result further confirmed that GnRH mRNA only distributed in some good-sized neurons in the posterior lobe (PL) and some pint-sized neurons in the lateral lobe (LL). In addition, by examining the expression of GnRH during gonadal development in ganglia, we found GnRH displayed higher expression in the female scallops, and showed significant high expression at the growing stage of female scallops in PVG. This study would contribute to gaining insight into the mechanism underlying reproduction regulation by GnRH in the scallop and help to provide a better understanding of reproductive neuroendocrine in mollusks.

Changes in testicular histomorphometry and ultrastructure of Leydig cells in adult male Japanese quail exposed to di (n-butyl) phthalate (DBP) during the prepubertal period

Phthalate esters, such as di(n-butyl) phthalate, (DBP), are synthetic chemical pollutants commonly used as plasticizers in the manufacture of plastics. In the present study, we investigated the effects of DBP in the testes of adult male quails (Coturnix cortunix japonica) exposed by oral gavage to variable doses of DBP (0 [control], 1, 10, 50, 200, and 400 mg/kgbw^-d), for 30 days during the prepubertal period, using histo-morphometric and ultrastructural techniques. Generally, significant decreases in seminiferous tubular diameter (STD) and epithelial height (SEH) were observed predominantly at the highest DBP doses (200 and 400 mg/kg), as compared to medium (50 mg/kg), and lowest doses (1 and 10 mg/kg) as well as the control group. Ultrastructurally, apparent dose-specific degenerative changes were observed in the Leydig cells. The lowest DBP doses (1 and 10 mg/kg) did not produce significant effects on Leydig cell ultrastructure, whereas, at the highest doses (200 and 400 mg/kg), the Leydig cells were remarkably conspicuous in the interstitium and appeared foamy. There was a preponderance of electron-lucent lipid droplets which crowded out the normal organelles of the cell, as well as increases in the number of dense bodies in the cytoplasm. The smooth endoplasmic reticulum (sER) was less obvious, compacted, and wedged between the abundant lipid droplets and mitochondria. Taken together, these findings indicate that pre-pubertal exposure of precocious quail birds to DBP, produced parameter-specific histometric tubular changes, as well as dose-dependent cyto-structural derangement of the Leydig cells; which consequently may lead to overt reproductive impairments in the adult bird in the environment.

Mutation pattern of cancer suppressor p53 gene in factory workers exposed to polypropylene and impact on their reproductive hormones

BACKGROUND

Polypropylene is a thermoplastic polymer playing the role of an endocrine disruptor that interferes with the union, emission, transport or elimination of normal hormones. Epidemiological information indicated the relation of endocrine-disturbing chemicals with prostate cancer, testis tumor and diminished fertility. p53 is a key tumor silencer gene. The present study aimed to evaluate luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels and the risk of p53 mutations as a result of exposure to polypropylene in non-tumorous adult male factory workers.

METHODS

In total, 150 (controls = 35, workers = 115) subjects were recruited. Groups were maintained according to the tenure of exposure G1 (1-5 years), G2 (6-10 years), G3 (11-15 years) and G4 (16-20 years). Concentrations of LH and FSH were determined through an enzyme-linked immunosorbent assay. Genotyping analysis was performed by polymerase chain reaction based gel electrophoresis followed by DNA sequencing. The structural and functional impact of the mutation on the p53 structure was evaluated using 50-ns molecular dynamics (MD) simulations and protein-DNA docking.

RESULTS

Mean plasma LH levels were significantly decreased in G1 (p > 0.05) as well as the G2, G3 and G4 (p > 0.001) groups. Similarly, FSH levels were significant decrease in G1 (p > 0.05), G2 (p > 0.01), G3 (p > 0.001) and G4 (p > 0.001) compared to the control group. Sequencing results found three variants i.e. g.13450 T>G, g.13430C>T and g.13737G>A. One of them was predicted to be disease-causing others are polymorphisms. MD simulation of missense mutation R273H showed no structural impact on the protein structure in MD simulation, but it resulted in weaker binding of p53 with the DNA that might lower the gene expression of cell cycle regulatory proteins.

CONCLUSIONS

These findings predict decreased fertility and risk of malignancies in the future. The spectrum of p53 mutations as a result of polypropylene exposure in the Pakistani population has not been investigated before. Further studies and meta-analyses are required to elucidate the role of different plasticizers in reproduction and cancer-causing risk factors in a larger population.

Addressing the Reciprocal Crosstalk between the AR and the PI3K/AKT/mTOR Signaling Pathways for Prostate Cancer Treatment

The reduction in androgen synthesis and the blockade of the androgen receptor (AR) function by chemical castration and AR signaling inhibitors represent the main treatment lines for the initial stages of prostate cancer. Unfortunately, resistance mechanisms ultimately develop due to alterations in the AR pathway, such as gene amplification or mutations, and also the emergence of alternative pathways that render the tumor less or, more rarely, completely independent of androgen activation. An essential oncogenic axis activated in prostate cancer is the phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, as evidenced by the frequent alterations of the negative regulator phosphatase and tensin homolog (PTEN) and by the activating mutations in PI3K subunits. Additionally, crosstalk and reciprocal feedback loops between androgen signaling and the PI3K/AKT/mTOR signaling cascade that activate pro-survival signals and play an essential role in disease recurrence and progression have been evidenced. Inhibitors addressing different players of the PI3K/AKT/mTOR pathway have been evaluated in the clinic. Only a limited benefit has been reported in prostate cancer up to now due to the associated side effects, so novel combination approaches and biomarkers predictive of patient response are urgently needed. Here, we reviewed recent data on the crosstalk between AR signaling and the PI3K/AKT/mTOR pathway, the selective inhibitors identified, and the most advanced clinical studies, with a focus on combination treatments. A deeper understanding of the complex molecular mechanisms involved in disease progression and treatment resistance is essential to further guide therapeutic approaches with improved outcomes.

Oral administration of VDAC1-derived small molecule peptides increases circulating testosterone levels in male rats

Cholesterol is the precursor of all steroid hormones, and the entry of cholesterol into the mitochondria is the rate-limiting step of steroidogenesis. Voltage-dependent anion channel (VDAC1) is an outer mitochondrial protein part of a multiprotein complex that imports cholesterol. We previously reported that intratesticular administration of a 25 amino acid peptide blocking the interaction between 14-3-3ϵ with VDAC1 increased circulating levels of testosterone. This fusion peptide was composed of a HIV-1 transactivator of transcription (TAT) protein transduction domain cell-penetrating peptide, a glycine linker, and amino acids 159-172 of VDAC1 (TV159-172). Here, we describe the development of a family of small molecules that increase circulating testosterone levels after an oral administration. We first characterized an animal model where TV159-172 was delivered subcutaneously. This subcutaneous model allowed us to study the interactions between TV159-172 and the hypothalamus-pituitary-gonadal axis (HPG) and identify the biologically active core of TV159-172. The core consisted of the tetrapeptide RVTQ, which we used as a platform to design synthetic peptide derivatives that can be administered orally. We developed a second animal model to test various derivatives of RVTQ and found 11 active compounds. Dose-response experiments identified 4 synthetic peptides that robustly increased androgen levels in a specific manner. We selected RdVTQ as the leading VDAC1-core derivative and profiled the response across the lifespan of Brown-Norway rats. In summary, we present the development of a new class of therapeutics that act within the HPG axis to increase testosterone levels specifically. This new class of small molecules self-regulates, preventing abuse.

Androgen receptor signaling and pyrethroids: Potential male infertility consequences

Infertility is a global health concern inflicting a considerable burden on the global economy and a severe socio-psychological impact. Approximately 15% of couples suffer from infertility globally, with a male factor contribution of approximately 50%. However, male infertility remains largely unexplored, as the burden of infertility is mostly assigned to female people. Endocrine-disrupting chemicals (EDCs) have been proposed as one of the factors causing male infertility. Pyrethroids represent an important class of EDCs, and numerous studies have associated pyrethroid exposure with impaired male reproductive function and development. Therefore, the present study investigated the potentially toxic effects of two common pyrethroids, cypermethrin and deltamethrin, on androgen receptor (AR) signaling. The structural binding characterization of cypermethrin and deltamethrin against the AR ligand-binding pocket was performed using Schrodinger's induced fit docking (IFD) approach. Various parameters were estimated, such as binding interactions, binding energy, docking score, and IFD score. Furthermore, the AR native ligand, testosterone, was subjected to similar experiments against the AR ligand-binding pocket. The results revealed commonality in the amino acid-binding interactions and overlap in other structural parameters between the AR native ligand, testosterone, and the ligands, cypermethrin and deltamethrin. The estimated binding energy values of cypermethrin and deltamethrin were very high and close to those calculated for AR native ligand, testosterone. Taken together, the results of this study suggested potential disruption of AR signaling by cypermethrin and deltamethrin, which may result in androgen dysfunction and subsequent male infertility.

Opioid replacement therapy with methadone or buprenorphine effects on male mice reproduction

RATIONALE

Opioid use disorders are commonly treated by long-acting agonist opioids including methadone and buprenorphine which could affect various aspects of male reproduction especially spermatogenesis.

OBJECTIVES

We aimed to determine whether detoxification with methadone or buprenorphine was associated with reproductive disorders in male mice.

METHODS

We orally induced morphine dependence in NMRI male mice, and then performed detoxification programs using either methadone or buprenorphine. Testis architecture and sperm parameters including sperm nuclear DNA integrity, mitochondrial activity, oxidative stress in seminal plasma, and routine sperm parameters were assessed to find the involved mechanisms.

RESULTS

The number of Leydig cells and the thickness of germinal epithelium reduced following morphine use and increased differently after detoxification with methadone or buprenorphine. Morphine dependence and detoxification with methadone and buprenorphine had different effects on sperm parameters. Morphine altered chromatin integrity, mitochondrial activity, and oxidative stress in sperm. Detoxification with methadone improved mitochondrial activity but worsened chromatin integrity, whereas detoxification with buprenorphine improved neither chromatin integrity nor mitochondrial activity. Seminal plasma oxidative stress was higher in the treated groups compared to control groups but was comparable among treatment groups. Our study revealed that long-term morphine use followed by detoxification with methadone or buprenorphine impairs testis structure and sperm parameters. Detoxification from morphine use with methadone and buprenorphine led to different preclinical outcomes in semen quality parameters, including chromatin integrity. Therefore, clinical detoxification protocols should be performed more cautiously, considering the desire of the individuals to reproduce.

Genome-wide alternation and effect of DNA methylation in the impairments of steroidogenesis and spermatogenesis after PM2.5 exposure

The effects of ambient fine particles on male reproductive health have raised widespread concern. The particular underlying mechanisms of the damage remain largely unclear and demand more research in new directions. Previous research has revealed that DNA methylation plays an important role in male reproductive development and is also vulnerable to environmental influences. However, there hasn't been enough investigation into the involvement of DNA methylation in PM_2.5-induced male reproductive toxicity. Here, we establish a real-time PM_2.5 exposure model and revealed that PM_2.5 exposure could lead to testicular dysfunction including spermatogenesis impairment and steroid hormone dysfunction. In particular, the decrease in the testicular global level of 5-methylcytosine (5mC) indicated a possible association of DNA methylation with testicular injury induced by PM_2.5 exposure. Further genome-wide methylation analysis revealed genomic hypomethylation of testicular DNA and identified more than 1000 differentially methylated regions in both CAP and UA versus FA, indicating that PM_2.5 exposure, even low-dose, could modulate the testicular methylome. Furthermore, integrated analysis of methylome and transcriptome identified some key methylated genes and networks, which may be involved in spermatogenesis and synthesis of steroid hormone. The testicular methylation levels of key genes especially Cyp11a1 and Pax8 raised, and their consequent reduced expression may impair the testosterone and sperm production process. Our research provides fundamental knowledge as well as novel insights into the possible involvement of DNA methylation in PM_2.5-induced male reproductive harm.

Pituitary gonadotroph-specific patterns of gene expression and hormone secretion

Pituitary gonadotrophs play a key role in reproductive functions by secreting luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The LH secretory activity of gonadotroph is controlled by hypothalamic gonadotropin-releasing hormone (GnRH) via GnRH receptors and is accompanied by only minor effects on high basal Lhb gene expression. The secretory profiles of GnRH and LH are highly synchronized, with the latter reflecting a depletion of prestored LH in secretory vesicles by regulated exocytosis. In contrast, FSH is predominantly released by constitutive exocytosis, and secretory activity reflects the kinetics of Fshb gene expression controlled by GnRH, activin, and inhibin. Here is a review of recent data to improve the understanding of multiple patterns of gonadotroph gene expression and hormone secretion.

Strong regulatory effects of vgll3 genotype on reproductive axis gene expression in juvenile male Atlantic salmon

Age at maturity is a major contributor to the diversity of life history strategies in organisms. The process of maturation is influenced by both genetics and the environment, and includes changes in levels of sex hormones and behavior, but the specific factors leading to variation in maturation timing are poorly understood. gnrh1 regulates the transcription of gonadotropin genes at pubertal onset in many species, but this gene is lacking in certain teleost species including Atlantic salmon (Salmo salar), which raises the possibility of the involvement of other important regulatory factors during this process. Earlier research has reported a strong association of alternative alleles of the vgll3 gene with maturation timing in Atlantic salmon, suggesting it as a potential candidate regulating reproductive axis genes. Here, we investigated the expression of reproductive axis genes in one-year-old Atlantic salmon males with immature gonads and different vgll3 genotypes during the spawning period. We detected strong vgll3 genotype-dependent differential expression of reproductive axis genes (such as fshb, lhb, amh and igf3) tested in the pituitary, and testis. In addition, we observed differential expression of jun (ap1) and nr5a1b (sf1), potential upstream regulators of gonadotropins in the pituitary, as well as axin2, id3, insl3, itch, ptgs2a and ptger4b, the downstream targets of amh and igf3 in the testis. Hereby, we provide evidence of strong vgll3 genotype-dependent transcriptional regulation of reproductive axis genes prior to sexual maturation and suggest alternative models for distinct actions of vgll3 genotypes on the related molecular processes.

Carbamate Pesticides: Shedding Light on Their Impact on the Male Reproductive System

Carbamates are widely used and known around the world as pesticides in spite of also having medical applications. This class of chemicals is classified as acetylcholinesterase inhibitors, blocking acetylcholine hydrolyzation in a reversible manner. Their lack of species selectivity and their reported high toxicity can induce, upon exposure, adverse outcomes in male fertility that may lead to infertility. In addition, they are also considered endocrine-disrupting chemicals and can interfere with the hypothalamic–pituitary–testicular axis, essential for the normal function of the male reproductive system, thus being able to provoke male reproductive dysfunctions. Although the molecular mechanisms are not fully understood, various signaling pathways, such as those mediated by acetylcholine or kisspeptin, are affected by exposure to carbamates, thus compromising steroidogenesis and spermatogenesis. Over the last decades, several studies, both in vitro and in vivo, have reported a myriad of negative effects of carbamates on the male reproductive system. In this review, an up-to-date overview of the impact of carbamates on the male reproductive system is discussed, with an emphasis on the role of these compounds on acetylcholine regulation and the male endocrine system.

Clinical utility of serum 17-hydroxyprogesterone as a marker for medical therapy for male infertility: recommendations based on clinical scenarios

Traditional serum hormone testing in the evaluation of male infertility consists of testosterone, follicle-stimulating hormone, luteinizing hormone, and estradiol. Based on these values, medical therapy is often initiated in an attempt to increase intratesticular testosterone levels and, in turn, promote spermatogenesis. While this hormone panel provides serum testosterone levels, it does not evaluate intratesticular testosterone, obviously an important factor that is critical for spermatogenesis. 17-hydroxyprogesterone (17-OHP) is an intermediate in the steroidal pathway of cholesterol to testosterone conversion that has recently demonstrated promise as an accurate serum biomarker for intratesticular testosterone. At present, 17-OHP has not been widely adopted as a clinical tool in the evaluation of male infertility, which likely stems, in part, from a lack of concrete indications for its use. In this review, we present five commonly encountered scenarios of male infertility where the utilization of 17-OHP has aided in the management and provided a more personalized approach to treatment.

Comparative transcriptome analysis identifies crucial candidate genes and pathways in the hypothalamic-pituitary-gonadal axis during external genitalia development of male geese

Background

All birds reproduce via internal fertilization, but only ~3% of male birds possess the external genitalia that allows for intromission. Waterfowl (e.g., duck and goose) are representatives of them, and the external genitalia development of male geese is directly related to mating ability. Notably, some male geese show abnormal external genitalia development during ontogenesis. However, until now little is known about the molecular mechanisms of the external genitalia development in goose. In the present study, comparative transcriptomic analyses were performed on the hypothalamus, pituitary gland, testis, and external genitalia isolated from the 245-day-old male Tianfu meat geese showing normal (NEGG, n = 3) and abnormal (AEGG, n = 3) external genitals in order to provide a better understanding of the mechanisms controlling the development of the external genitalia in aquatic bird species.

Results

There were 107, 284, 2192, and 1005 differentially expressed genes (DEGs) identified in the hypothalamus, pituitary gland, testis and external genitalia between NEGG and AEGG. Functional enrichment analysis indicated that the DEGs identified in the hypothalamus were mainly enriched in the ECM-receptor interaction pathway. The ECM-receptor interaction, focal adhesion, and neuroactive ligand-receptor interaction pathways were significantly enriched by the DEGs in the pituitary gland. In the testis, the DEGs were enriched in the neuroactive ligand-receptor interaction, cell cycle, oocyte meiosis, and purine metabolism. In the external genitalia, the DEGs were enriched in the metabolic, neuroactive ligand-receptor interaction, and WNT signaling pathways. Furthermore, through integrated analysis of protein-protein interaction (PPI) network and co-expression network, fifteen genes involved in the neuroactive ligand-receptor interaction and WNT signaling pathways were identified, including KNG1, LPAR2, LPAR3, NPY, PLCB1, AVPR1B, GHSR, GRM3, HTR5A, FSHB, FSHR, WNT11, WNT5A, WIF1, and WNT7B, which could play crucial roles in the development of goose external genitalia.

Conclusions

This study is the first systematically comparing the hypothalamus, pituitary gland, testis, and external genitalia transcriptomes of male geese exhibiting normal and abnormal external genitals. Both bioinformatic analysis and validation experiments indicated that the neuroactive ligand-receptor interaction pathway could regulate the WNT signaling pathway through PLCB1 to control male goose external genitalia development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08374-2.

The Hippo Pathway Effectors YAP and TAZ Regulate LH Release by Pituitary Gonadotrope Cells in Mice

The Hippo transcriptional coactivators YAP and TAZ exert critical roles in morphogenesis, organ size determination and tumorigenesis in many tissues. Although Hippo kinase cascade activity was recently reported in the anterior pituitary gland in mice, the role of the Hippo effectors in regulating gonadotropin production remains unknown. The objective of this study was therefore to characterize the roles of YAP and TAZ in gonadotropin synthesis and secretion. Using a conditional gene targeting approach (cKO), we found that gonadotrope-specific inactivation of Yap and Taz resulted in increased circulating levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in adult male mice, along with increased testosterone levels and testis weight. Female cKO mice had increased circulating LH (but not FSH) levels, which were associated with a hyperfertility phenotype characterized by higher ovulation rates and larger litter sizes. Unexpectedly, the loss of YAP/TAZ did not appear to affect the expression of gonadotropin subunit genes, yet both basal and GnRH-induced LH secretion were increased in cultured pituitary cells from cKO mice. Likewise, pharmacologic inhibition of YAP binding to the TEAD family of transcription factors increased both basal and GnRH-induced LH secretion in LβT2 gonadotrope-like cells in vitro without affecting Lhb expression. Conversely, mRNA levels of ChgA and SgII, which encode key secretory granule cargo proteins, were decreased following pharmacologic inhibition of YAP/TAZ, suggesting a mechanism whereby YAP/TAZ regulate the LH secretion machinery in gonadotrope cells. Together, these findings represent the first evidence that Hippo signaling may play a role in regulating pituitary LH secretion.

Cyp17a2 is involved in testicular development and fertility in male Nile tilapia, Oreochromis niloticus

BACKGROUND

Steroid hormones play an essential role in many reproductive processes of vertebrates. Previous studies revealed that teleost-specific Cyp17a2 (cytochrome P450 family 17 subfamily a 2) might be required for the production of cortisol in the head-kidney and 17α,20β-dihydroxy-4-pregnen-3-one (DHP) in ovary during oocyte maturation. However, the role of Cyp17a2 in male reproduction remains to be largely unknown. The aim of this study was to explore the essentiality of cyp17a2 gene in male steroidogenesis, spermatogenesis, and male fertility.

METHODS

A homozygous mutation line of cyp17a2 gene was constructed in tilapia by CRISPR/Cas9 gene editing technology. The expression level of germ cell and meiosis-related genes and steroidogenic enzymes were detected by qRT-PCR, IHC, and Western blotting. EIA and LC-MS/MS assays were used to measure the steroid production levels. And sperm quality was examined by Sperm Quality Analyzer software.

RESULTS

In this study, cyp17a2 gene mutation resulted in the significant decline of serum DHP and cortisol levels. On the contrary, significant increases in intermediate products of cortisol and DHP were found in cyp17a2-/- male fish. The deficiency of cyp17a2 led to the arrest of meiotic initiation in male fish revealing as the reduction of the expression of germ cell-related genes (vasa, piwil, oct4) and meiosis-related genes (spo11 and sycp3) by 90 dah. Afterwards, spermatogenesis was gradually recovered with the development of testis in cyp17a2-/- males, but it showed a lower sperm motility and reduced fertility compared to cyp17a2+/+ XY fish. Deletion of cyp17a2 led to the abnormal upregulation of steroidogenic enzymes for cortisol production in the head-kidney. Moreover, unaltered serum androgens and estrogens, as well as unchanged related steroidogenic enzymes were found in the testis of cyp17a2-/- male fish.

CONCLUSION

This study proved that, for the fist time, Cyp17a2 is indispensable for cortisol and DHP production, and cyp17a2 deficiency associated curtailed meiotic initiation and subfertility suggesting the essentiality of DHP and cortisol in the male fertility of fish.

Cyp17a1 is Required for Female Sex Determination and Male Fertility by Regulating Sex Steroid Biosynthesis in Fish

In teleost fish, sex steroids are involved in sex determination, sex differentiation, and fertility. Cyp17a1 (Cytochrome P450 family 17 subfamily A member 1) is thought to play essential roles in fish steroidogenesis. Therefore, to further understand its roles in steroidogenesis, sex determination, and fertility in fish, we constructed a cyp17a1 gene mutant in Nile tilapia (Oreochromis niloticus). In XX fish, mutation of the cyp17a1 gene led to a female-to-male sex reversal with a significant decline in 17β-estradiol (E2) and testosterone (T) production, and ectopic expression of male-biased markers (Dmrt1 and Gsdf) in gonads from the critical window of sex determination. Sex reversal was successfully rescued via T or E2 administration, and ovarian characteristics were maintained after termination of E2 supplementation in the absence of endogenous estrogen production in cyp17a1-/- XX fish. Likewise, deficiencies in T and 11-ketotestosterone (11-KT) production in both cyp17a1-/- XX sex-reversed males and cyp17a1-/- XY mutants resulted in meiotic initiation delays, vas deferens obstruction and sterility due to excessive apoptosis and abnormal mitochondrial morphology. However, 11-KT treatment successfully rescued the dysspermia to produce normal sperm in cyp17a1-/- male fish. Significant increases in gonadotropic hormone (gth) and gth receptors in cyp17a1-/- mutants may excessively upregulate steroidogenic gene expression in Leydig cells through a feedback loop. Taken together, our findings demonstrate that Cyp17a1 is indispensable for E2 production, which is fundamental for female sex determination and differentiation in XX tilapia. Additionally, Cyp17a1 is essential for T and 11-KT production, which further promotes spermatogenesis and fertility in XY males.

Effects of prenatal chlorocholine chloride exposure on pubertal development and reproduction of male offspring in rats

Chlorocholine chloride (CCC) promote plant growth as a regulator. Emerging evidence by our group showed that CCC might restrain the puberty onset and impair the reproductive functions in male rats through HPT axis. In this study, we further investigated the effects of prenatal CCC exposure on pubertal development, reproduction of male offspring in rats and explored the underlying mechanisms. The results showed that CCC of 137.5 and 200 mg/kg bw/day delayed the age of preputial separation (PPS), decreased the sperm motility of male offspring. PP1γ2 which is an essential protein in spermatogenesis reduced in 137.5 and 200 mg/kg bw/day groups. Crucial hormones involved in hypothalamic-puititary-testicular (HPT) axis decreased at postnatal day (PND) 30. It was indicated that CCC exposure in pregnancy might disturb the pubertal development, reproductive functions of male offspring through HPT axis and disturb the sperm motility through PP1γ2.

Comprehensive transcriptome analysis of hypothalamus reveals genes associated with disorders of sex development in pigs

XX sex reversal, also called XX disorders of sex development (XX-DSD), is a condition affecting the development of the gonads or genitalia, and is relatively common in pigs. However, its genetic etiology and transcriptional regulation mechanism in the hypothalamic-pituitary-gonadal axis (HPGA) remain mostly unknown. XX-DSD (SRY-negative) pigs and normal sows were selected by external genitalia observation. The hypothalamus, which is the integrated center of the HPGA was sampled for whole-transcriptome RNA-seq. The role of DEmiRNA was validated by its overexpression and knockdown in vitro. A total of 1,258 lncRNAs, 1,086 mRNAs, and 61 microRNAs differentially expressed in XX-DSD pigs compared with normal female pigs. Genes in the hormone biosynthesis and secretion pathway significantly up-regulated, and the up-regulation of GNRH1, KISS1 and AVP may associate with the abnormal secretion of GnRH. We also predicted the lncRNA-miRNA-mRNA co-expression triplets and constructed three competing endogenous RNA (ceRNA) potentially associated with XX-DSD. Functional enrichment studies suggested that TCONS_00340886, TCONS_00000204 and miR-181a related to GnRH secretion. Further, miR-181a inhibitor up-regulated GNRH1, PAK6, and CAMK4 in the GT1-7 cells. Conversely, transfection of miR-181a mimics obtained the opposite trends. The expression levels of FSHR, LHR, ESR1 and ESR2 were significantly higher in XX-DSD gondas than those in normal sows. Taken together, we proposed that the balance of endocrine had broken in XX-DSD pigs. The current study is the first to examine the transcriptomic profile in the hypothalamus of XX-DSD pigs. It provides new insight into coding and non-coding RNAs that may be associated with DSD in pigs.

Pineal gland transcriptomic profiling reveals the differential regulation of lncRNA and mRNA related to prolificacy in STH sheep with two FecB genotypes

BACKGROUND

Long noncoding RNA (lncRNA) has been identified as important regulator in hypothalamic-pituitary-ovarian axis associated with sheep prolificacy. However, little is known of their expression pattern and potential roles in the pineal gland of sheep. Herein, RNA-Seq was used to detect transcriptome expression pattern in pineal gland between follicular phase (FP) and luteal phase (LP) in FecB^BB (MM) and FecB⁺⁺ (ww) STH sheep, respectively, and differentially expressed (DE) lncRNAs and mRNAs associated with reproduction were identified.

RESULTS

Overall, 135 DE lncRNAs and 1360 DE mRNAs in pineal gland between MM and ww sheep were screened. Wherein, 39 DE lncRNAs and 764 DE mRNAs were identified (FP vs LP) in MM sheep, 96 DE lncRNAs and 596 DE mRNAs were identified (FP vs LP) in ww sheep. Moreover, GO and KEGG enrichment analysis indicated that the targets of DE lncRNAs and DE mRNAs were annotated to multiple biological processes such as phototransduction, circadian rhythm, melanogenesis, GSH metabolism and steroid biosynthesis, which directly or indirectly participate in hormone activities to affect sheep reproductive performance. Additionally, co-expression of lncRNAs-mRNAs and the network construction were performed based on correlation analysis, DE lncRNAs can modulate target genes involved in related pathways to affect sheep fecundity. Specifically, XLOC_466330, XLOC_532771, XLOC_028449 targeting RRM2B and GSTK1, XLOC_391199 targeting STMN1, XLOC_503926 targeting RAG2, XLOC_187711 targeting DLG4 were included.

CONCLUSION

All of these differential lncRNAs and mRNAs expression profiles in pineal gland provide a novel resource for elucidating regulatory mechanism underlying STH sheep prolificacy.

Abatement of the dysfunctional hypothalamic-pituitary-gonadal axis due to ciprofloxacin administration by selenium in male rats

The present study examined the influence of selenium on ciprofloxacin-mediated reproductive dysfunction in rats. The research design consisted of five groups of eight animals each. The rats were administered 135 mg/kg body weight of ciprofloxacin per se or simultaneously with selenium at 0.25 and 0.5 mg/kg for 15 uninterrupted days. Antioxidant and inflammatory indices were assayed using the testes, epididymis, and hypothalamus of the animals after sacrifice. Results revealed that ciprofloxacin treatment per se interfered with the reproductive axis as demonstrated by diminished serum hormonal levels, sperm quality, and enzymatic indices of testicular function, which were, however, abrogated following selenium co-treatment. Besides this, administration of selenium attenuated the depletion of glutathione level, inhibition of catalase, superoxide dismutase, glutathione-S-transferase and glutathione peroxidase activities with a concomitant reduction in reactive oxygen and nitrogen species, and lipid peroxidation in ciprofloxacin-treated in rats. Selenium treatment also mitigated ciprofloxacin-mediated elevation in nitric oxide level and of myeloperoxidase activity as well as histological lesions in the animals. Overall, selenium attenuated impairment in the male reproductive axis due to ciprofloxacin treatment through abatement of inflammation and oxidative stress in rats.

Effects of Haima Duobian Pill in a Rat Model of Kidney Yang Deficiency Syndrome

Objective

Modern research shows that Haima Duobian pill (HDP) can relieve the kidney yang deficiency syndrome (KYDS), but the mechanism is still unclear. The aim of this work was to study the effects of HDP in a rat model of KYDS.

Materials and Methods

The network pharmacology methods were used to predict the therapeutic effects of Haima Duobian pill. Adenine was used to establish the rat model of kidney yang deficiency syndrome. The general physical signs of rats were observed after different doses of Haima Duobian pill (HDP) were given. Serum cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T), estradiol (E2), and gonadotropin-releasing hormone (GnRH) levels were determined using enzyme-linked immunosorbent assay (ELISA) kits. Then, the histopathologic changes and sperm activity were detected.

Results

HDP could improve the general signs of kidney yang deficiency syndrome rats. After the rats were treated with HDP, the expression of cGMP and E2 was significantly inhibited and the expression of cAMP and T was significantly increased. The pathological damage of testis, epididymis, and seminal vesicle was alleviated, and the sperm activity was improved.

Conclusion

For adenine-induced kidney yang deficiency syndrome in rats, HDP had a significant therapeutic effect.

Molecular mechanism of reproductive toxicity induced by beta-cypermethrin in zebrafish

Beta-cypermethrin, a type II synthetic pyrethroid insecticide, is widely used in pest control. Several studies have demonstrated that beta-cypermethrin can affect the reproductive system of mammals. However, there is still a scarcity of information about the reproductive toxicity to fish induced by beta-cypermethrin and its molecular mechanism. Therefore, this study was conducted to address this scientific question, in which the adult zebrafish were exposed to 0 (blank control), 0 (acetone solvent control), 0.1, 0.5, and 2.5 μg/L of beta-cypermethrin for 21 days. A decrease in cumulative egg production of zebrafish was observed, indicating that beta-cypermethrin had a negative impact on reproductive capacity of zebrafish. Regarding the histomorphological analysis of gonads, the delay of gonadal development was observed after exposure for 21 days. In addition, significant changes in plasma 17β-estradiol (E2) and testosterone (T) were found in zebrafish. Further exploration showed that the transcription levels of hypothalamic-pituitary-gonadal (HPG) axis-related genes were remarkably changed, which corresponded well with the alterations of hormone levels. These results demonstrated that beta-cypermethrin might have an adverse effect on the reproduction system of zebrafish through delaying gonadal development, disturbing sex hormone secretion, and affecting HPG axis gene expression. This study suggests that beta-cypermethrin poses a potential threat to the reproduction of fish populations, and the toxicity assessment of beta-cypermethrin plays a vital role in the environmental risk assessment of pesticides.

A Testis-Specific Long Noncoding RNA, Start, Is a Regulator of Steroidogenesis in Mouse Leydig Cells

The testis expresses many long noncoding RNAs (lncRNAs), but their functions and overview of lncRNA variety are not well understood. The mouse Prss/Tessp locus contains six serine protease genes and two lncRNAs that have been suggested to play important roles in spermatogenesis. Here, we found a novel testis-specific lncRNA, Start (Steroidogenesis activating lncRNA in testis), in this locus. Start is 1822 nucleotides in length and was found to be localized mostly in the cytosol of germ cells and Leydig cells, although nuclear localization was also observed. Start-knockout (KO) mice generated by the CRISPR/Cas9 system were fertile and showed no morphological abnormality in adults. However, in adult Start-KO testes, RNA-seq and qRT-PCR analyses revealed an increase in the expression of steroidogenic genes such as Star and Hsd3b1, while ELISA analysis revealed that the testosterone levels in serum and testis were significantly low. Interestingly, at 8 days postpartum, both steroidogenic gene expression and testosterone level were decreased in Start-KO mice. Since overexpression of Start in two Leydig-derived cell lines resulted in elevation of the expression of steroidogenic genes including Star and Hsd3b1, Start is likely to be involved in their upregulation. The increase in expression of steroidogenic genes in adult Start-KO testes might be caused by a secondary effect via the androgen receptor autocrine pathway or the hypothalamus-pituitary-gonadal axis. Additionally, we observed a reduced number of Leydig cells at 8 days postpartum. Collectively, our results strongly suggest that Start is a regulator of steroidogenesis in Leydig cells. The current study provides an insight into the overall picture of the function of testis lncRNAs.

FXRα modulates leydig cell endocrine function in mouse

The hypothalamic-pituitary axis exert a major control over endocrine and exocrine testicular functions. The hypothalamic-pituitary axis corresponds to a cascade with the Gonadotropin Releasing Hormone secreted by the hypothalamus, which stimulates the synthesis and the release of Luteinizing Hormone (LH) and Follicle Stimulating Hormone by the gonadotropic cells of the anterior pituitary. The LH signaling pathway controls the steroidogenic activity of the Leydig cells via the activation of the luteinizing hormone/choriogonadotropin receptor. In order to avoid a runaway system, sex steroids exert a negative feedback within hypothalamus and pituitary. Testicular steroidogenesis is locally controlled within Leydig cells. The present work reviews some local regulations of steroidogenesis within the Leydig cells focusing mainly on the roles of the Farnesoid-X-Receptor-alpha and its interactions with several orphan members of the nuclear receptor superfamily. Further studies are required to reinforce our knowledge of the regulation of testicular endocrine function, which is necessary to ensure a better understanding of fertility disorders and then proposed an adequate treatment of the diseases.

The impact of endocrine-disrupting chemical exposure in the mammalian hypothalamic-pituitary axis

The hypothalamic-pituitary axis (HP axis) plays a critical and integrative role in the endocrine system control to maintain homeostasis. The HP axis is responsible for the hormonal events necessary to regulate the thyroid, adrenal glands, gonads, somatic growth, among other functions. Endocrine-disrupting chemicals (EDCs) are a worldwide public health concern. There is growing evidence that exposure to EDCs such as bisphenol A (BPA), some phthalates, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and biphenyls (PBBs), dichlorodiphenyltrichloroethane (DDT), tributyltin (TBT), and atrazine (ATR), is associated with HP axis abnormalities. EDCs act on hormone receptors and their downstream signaling pathways and can interfere with hormone synthesis, metabolism, and actions. Because the HP axis function is particularly sensitive to endogenous hormonal changes, disruptions by EDCs can alter HP axis proper function, leading to important endocrine irregularities. Here, we review the evidence that EDCs could directly affect the mammalian HP axis function.

Emerging roles of APLN and APELA in the physiology and pathology of the female reproductive system

APLN, APELA and their common receptor APLNR (composing the apelinergic axis) have been described in various species with extensive body distribution and multiple physiological functions. Recent studies have witnessed emerging intracellular cascades triggered by APLN and APELA which play crucial roles in female reproductive organs, including hypothalamus-pituitary-gonadal axis, ovary, oviduct, uterus and placenta. However, a comprehensive summary of APLN and APELA roles in physiology and pathology of female reproductive system has not been reported to date. In this review, we aim to concentrate on the general characteristics of APLN and APELA, as well as their specific physiological roles in female reproductive system. Meanwhile, the pathological contexts of apelinergic axis dysregulation in the obstetrics and gynecology are also summarized here, suggesting its potential prospect as a diagnostic biomarker and/or therapeutic intervention in the polycystic ovary syndrome, ovarian cancer, preeclampsia and gestational diabetes mellitus.

Potential GnRH and steroidogenesis pathways in the scallop Patinopecten yessoensis

Gonadotropin-releasing hormone (GnRH) controls synthesis of sex steroid hormones through hypothalamic-pituitary-gonadal (HPG) axis in vertebrates. But in mollusks, research on GnRH and steroidogenesis pathways is still limited. In this study, we first identified two gonadotropin receptor like genes (LGR and LGR5L) and four steroidogenesis-related genes (CYP17A, HSD17B12, HSD3B1 and HSD3B2) in the scallop Patinopecten yessoensis. By examining the expression of 11 genes in the ganglia and/or gonad as well as the concentration of progesterone, testosterone and estradiol in the gonad, we postulate that a potential GnRH signaling pathway (GnRH-GnRHR-GPB5-LGR/LGR5L) in the cerebral and pedal ganglia (CPG) and steroidogenesis pathway (CYP17A, HSD17B12 and HSD3B1) in the gonad are involved in regulating sex steroid hormones. E₂/T index that indicates aromatase activity is higher in the ovary than testis and is positively correlated with the expression of FOXL2 in the gonad, implying the presence of aromatase in the scallop. In addition, we confirmed that expression of most of the downstream genes in the two pathways was significantly elevated after injection of mature py-GnRH peptide. This study would contribute to a new understanding of the molecular basis underlying reproduction regulation by GnRH in mollusks.

Selective effects of protein 4.1N deficiency on neuroendocrine and reproductive systems

Protein 4.1N, a member of the protein 4.1 family, is highly expressed in the brain. But its function remains to be fully defined. Using 4.1N^−/− mice, we explored the function of 4.1N in vivo. We show that 4.1N^−/− mice were born at a significantly reduced Mendelian ratio and exhibited high mortality between 3 to 5 weeks of age. Live 4.1N^−/− mice were smaller than 4.1N^+/+ mice. Notably, while there were no significant differences in organ/body weight ratio for most of the organs, the testis/body and ovary/body ratio were dramatically decreased in 4.1N^−/− mice, demonstrating selective effects of 4.1N deficiency on the development of the reproductive systems. Histopathology of the reproductive organs showed atrophy of both testis and ovary. Specifically, in the testis there is a lack of spermatogenesis, lack of leydig cells and lack of mature sperm. Similarly, in the ovary there is a lack of follicular development and lack of corpora lutea formation, as well as lack of secretory changes in the endometrium. Examination of pituitary glands revealed that the secretory granules were significantly decreased in pituitary glands of 4.1N^−/− compared to 4.1N^+/+. Moreover, while GnRH was expressed in both neuronal cell body and axons in the hypothalamus of 4.1N^+/+ mice, it was only expressed in the cell body but not the axons of 4.1N^-/- mice. Our findings uncover a novel role for 4.1N in the axis of hypothalamus-pituitary gland-reproductive system.

Manganese exposure caused reproductive toxicity of male mice involving activation of GnRH secretion in the hypothalamus by prostaglandin E2 receptors EP1 and EP2

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

Restorative functions of Autologous Stem Leydig Cell transplantation in a Testosterone-deficient non-human primate model

Rationale: Stem Leydig cells (SLCs) transplantation can restore testosterone production in rodent models and is thus a potential solution for treating testosterone deficiency (TD). However, it remains unknown whether these favorable effects will be reproduced in more clinically relevant large-animal models. Therefore, we assessed the feasibility, safety and efficacy of autologous SLCs transplantation in a testosterone-deficient non-human primate (NHP) model.

Methods: Cynomolgus monkey SLCs (CM-SLCs) were isolated from testis biopsies of elderly (> 19 years) cynomolgus monkeys by flow cytometry. Autologous CM-SLCs were injected into the testicular interstitium of 7 monkeys. Another 4 monkeys were injected the same way with cynomolgus monkey dermal fibroblasts (CM-DFs) as controls. The animals were then examined for sex hormones, semen, body composition, grip strength, and exercise activity.

Results: We first isolated CD271⁺ CM-SLCs which were confirmed to expand continuously and show potential to differentiate into testosterone-producing Leydig cells (LCs) in vitro. Compared with CM-DFs transplantation, engraftment of autologous CM-SLCs into elderly monkeys could significantly increase the serum testosterone level in a physiological pattern for 8 weeks, without any need for immunosuppression. Importantly, CM-SLCs transplantation recovered spermatogenesis and ameliorated TD-related symptoms, such as those related to body fat mass, lean mass, bone mineral density, strength and exercise capacity.

Conclusion: For the first time, our short-term observations demonstrated that autologous SLCs can increase testosterone levels and ameliorate relevant TD symptoms in primate models. A larger cohort with long-term follow-up will be required to assess the translational potential of autologous SLCs for TD therapy.

The effect of underweight on female and male reproduction

Chronic energy deficiency can impair the hypothalamic-pituitary-gonadal (HPG) axis and lead to hypothalamic anovulation in underweight women. This review presents the syndromes related to underweight status that are associated with infertility, summarizes the underlying mechanisms, and reviews the available treatment options. Eating disorders, such as anorexia nervosa (AN), constitute the most common cause of infertility in underweight women, who, in addition, experience miscarriages, and sexual dysfunction. The relative energy deficiency in sports (RED-S; former terminology: athlete's triad) involves menstrual dysfunction due to low energy availability, which results in anovulation. Moreover, lipodystrophies, malnutrition, starvation, systematic illnesses (malignancies, endocrinopathies, infectious diseases, advanced chronic diseases, neurologic illnesses), and the utilization of drugs can cause excessive weight loss. They may result in fertility problems due to the loss of adipose tissue and the subsequent hormonal disturbances. Each of these conditions requires multidisciplinary management. Nutritional counseling should target the restoration of energy balance by increasing intake and reducing output. Medical treatment, recommended only for patients who did not respond to standard treatment, may include antipsychotics, antidepressants, or leptin administration. Finally, psychiatric treatment is considered an integral part of the standard treatment.

Effects and mechanisms of pyrethroids on male reproductive system

Synthetic pyrethroids are used as insecticides in agriculture and a variety of household applications worldwide. Pyrethroids are widely distributed in all environmental compartments and the general populations are exposed to pyrethroids through various routes. Pyrethroids have been identified as endocrine-disrupting chemicals (EDCs) which are responsible for the male reproductive impairments. The data confirm pyrethroids cause male reproductive damages. The insecticides exert the toxic effects on male reproductive system through various complex mechanisms including antagonizing androgen receptor (AR), inhibiting steroid synthesis, affecting the hypothalamic-pituitary-gonadal (HPG) axis, acting as estrogen receptor (ER) modulators and inducing oxidative stress. The mechanisms of male reproductive toxicity of pyrethroids involve multiple targets and pathways. The review will provide further insight into pyrethroid-induced male reproductive toxicity and mechanisms, which is crucial to preserve male reproductive health.