Male Reproductive Axis Research Articles

7441 KNDy Neurons and the Control of the Gonadotropic Axis in Midgestation Fetal Sheep

Abstract Disclosure: R. Amodei: None. S.S. Jonker: None. K. Gribbin: None. E. Lazen: None. C.T. Estill: None. C.E. Roselli: None. Recent evidence suggests that the neuropeptide kisspeptin (Kiss) plays a role to activate and regulate the male reproductive axis to secrete LH and testosterone during a time in gestation critical for brain sexual differentiation. KNDy neurons, an acronym for Kiss neurons that co-express neurokinin B (NKB) and dynorphin (Dyn), regulate pulsatile GnRH/LH secretion and are present in the hypothalamic arcuate nucleus of midgestation sheep fetuses. Notably, KNDy neurons are more abundant in female than in male fetuses. We hypothesize that KNDy-GnRH signaling is established during midgestation and that negative feedback mediated through KNDy neurons serves to regulate levels of testosterone needed for brain masculinization. In the current study, we used immunofluorescence histochemistry to assess the effect of testosterone manipulations on the number of arcuate Kiss neurons in male and female fetuses. In addition, we employed unanesthetized cannulated midgestation fetal sheep to test the effects of KNDy peptides on LH secretion and characterize receptor specificity in a real-time physiological context. We found that biweekly administration of testosterone propionate to the dam from Day 30–58 of gestation significantly increased (P < 0.05) plasma testosterone concentrations, which resulted in a significant decrease (P < 0.05) in both mean plasma LH concentrations and the number of arcuate Kiss neurons in female lamb fetuses. Conversely, chemical castration of midgestation male fetuses by treatment with the GnRH antagonist degarelix from day 60 – 90 of gestation resulted in a significant decrease (P < 0.05) in mean plasma LH and testosterone concentrations that was accompanied by a significant increase (P < 0.05) in the number of arcuate Kiss neurons. In unanesthetized fetuses, we found that bolus administration of both KP-10 (Kiss agonist) and senktide (NKB agonist) elicited a robust release of LH within 15 min. Treatment with the NK3 receptor antagonist SB222200 effectively blocked the senktide response, whereas the Kiss1 receptor antagonist P271 appeared to have an effect in males only. Blocking κ-opiate receptor (KOR) with a bolus injection of the KOR antagonist PF4455242 resulted in a significant increase in LH release and enhanced the stimulatory effect of senktide. These results support the hypothesis that KNDy neurons play a regulatory role in GnRH and hence gonadotropin secretion in sheep fetuses and serve as targets for negative feedback in males for maintaining a stable androgen environment crucial for brain masculinization. Supported by NIH Grant OD11047 to CER. Presentation: 6/1/2024

Short term effects of intraarticular triamcinolone acetonide injection on serum testosterone, luteinizing hormone, and follicle stimulating hormone levels in male veterans: A prospective pilot study.

Despite the common practice of intraarticular corticosteroid injections (ICSIs) for peripheral joint disease, little is known about their systemic effects on the hypothalamic-pituitary-gonadal axis. To assess the short-term effects of ICSIs on serum testosterone (T), luteinizing hormone (LH), and follicle stimulating hormone (FSH) levels together with changes in Shoulder Pain and Disability Index (SPADI) scores in a veteran population. Prospective pilot study. Outpatient musculoskeletal clinic. Thirty male veterans, median age 50 (range 30-69) years. Ultrasound-guided glenohumeral joint injection using 3 mL of 1% lidocaine HCl and 1 mL of 40 mg triamcinolone acetonide (Kenalog). Serum T, FSH, and LH levels, Quantitative Androgen Deficiency in the Aging Male (qADAM), and SPADI questionnaires at baseline, 1, and 4 week(s) post procedure. At 1 week post injection, serum T levels decreased by 56.8 ng/dL (95% confidence interval (CI): 91.8, 21.7, p = .002) compared with baseline. Between 1 and 4 weeks post injection, serum T levels increased by 63.9 ng/dL (95% CI: 26.5, 101.2, p = .001), recovering to near baseline levels. SPADI scores were reduced at 1 week (-18.3, 95% CI: -24.4, -12.1, p < .001) and 4 weeks (-14.5, 95% CI -21.1, -7.9, p < .001). A single ICSI can temporarily suppress the male gonadal axis. Future studies are needed to evaluate for long-term effects of multiple injections at a single setting and/or higher corticosteroid doses on male reproductive axis function.

Is methotrexate safe for men with an immune-mediated inflammatory disease and an active desire to become a father? Results of a prospective cohort study (iFAME-MTX)

IntroductionCurrent scientific evidence guiding the decision whether men with an active desire to become a father should be treated with methotrexate (MTX) remains controversial. We aimed to prospectively evaluate the...

Transcriptomic Changes Following Induced De-Masculinisation of Australian Red Claw Crayfish Cherax quadricarinatus.

The Australian red claw crayfish Cherax quadricarinatus, an emerging species within the freshwater aquaculture trade, is not only an ideal species for commercial production due to its high fecundity, fast growth, and physiological robustness but also notoriously invasive. Investigating the reproductive axis of this species has been of great interest to farmers, geneticists, and conservationists alike for many decades; however, aside from the characterisation of the key masculinising insulin-like androgenic gland hormone (IAG) produced by the male-specific androgenic gland (AG), little remains known about this system and the downstream signalling cascade involved. This investigation used RNA interference to silence IAG in adult intersex C. quadricarinatus (Cq-IAG), known to be functionally male but genotypically female, successfully inducing sexual redifferentiation in all individuals. To investigate the downstream effects of Cq-IAG knockdown, a comprehensive transcriptomic library was constructed, comprised of three tissues within the male reproductive axis. Several factors known to be involved in the IAG signal transduction pathway, including a receptor, binding factor, and additional insulin-like peptide, were found to not be differentially expressed in response to Cq-IAG silencing, suggesting that the phenotypic changes observed may have occurred through post-transcriptional modifications. Many downstream factors displayed differential expression on a transcriptomic level, most notably related to stress, cell repair, apoptosis, and cell proliferation. These results suggest that IAG is required for sperm maturation, with necrosis of arrested tissue occurring in its absence. These results and the construction of a transcriptomic library for this species will inform future research involving reproductive pathways as well as biotechnological developments in this commercially and ecologically significant species.

Impulsive time series modeling with application to luteinizing hormone data.

This work considers the estimation of impulsive time series pertaining to biomedical systems and, in particular, to endocrine ones. We assume a signal model in the form of the output of a continuous linear time-invariant system driven by a sequence of instantaneous impulses, which concept is utilized here, in particular, for modeling of the male reproductive hormone axis. An estimation method to identify the impulsive sequence and the continuous system dynamics from sampled measurements of the output is proposed. Hinging on thorough mathematical analysis, the method improves upon a previously developed least-squares algorithm by resolving the trade-off between model fit and input sparsity, thus removing the need for manual tuning of user-defined estimation algorithm parameters. Experiments with synthetic data and Markov chain Monte-Carlo estimation demonstrate the viability of the proposed method, but also indicate that measurement noise renders the estimation problem ill-posed, as multiple estimates along a curve in the parameter space yield similar fits to data. The method is furthermore applied to clinical luteinizing hormone data collected from healthy males and, for comparability, one female, with similar results. Comparison between the estimated and theoretical elimination rates, as well as simulation of the estimated models, demonstrate the efficacy of the method. The sensitivity of the impulse distribution to the estimated elimination rates is investigated on a subject-specific data subset, revealing that the input sequence and elimination rate estimates can be interdependent. The dose-dependent effect of a selective gonadotropin releasing hormone receptor antagonist on the frequency and weights of the estimated impulses is also analyzed; a significant impact of the medication on the impulse weights is confirmed. To demonstrate the feasibility of the estimation approach for other hormones with pulsatile secretion, the modeling of cortisol data sets collected from three female adolescents was performed.

Dietary myricetin assuages atrazine-mediated hypothalamic-pituitary-testicular axis dysfunction in rats.

Atrazine (ATZ) exposure is associated with reproductive dysfunction in both animals and humans. Myricetin, a flavonoid compound, is well documented for its numerous pharmacological activities. However, the impact of myricetin on the atrazine-mediated dysfunctional hypothalamic-pituitary-testicular axis is not known. This study investigated the role of myricetin on the atrazine-induced alterations in the male reproductive axis in rats orally gavaged with ATZ alone (50mg/kg) or co-treated with ATZ + myricetin (MYR) at 5, 10, and 20mg/kg for 30 consecutive days. Myricetin assuaged ATZ-induced reductions in intra-testicular testosterone, serum follicle-stimulating hormone, luteinizing hormone, and testosterone, coupled with decreases in alkaline phosphatase, acid phosphatase, lactate dehydrogenase, and glucose-6-phosphate dehydrogenase activities. Also, MYR treatment improved epididymal sperm count and motility and decreased sperm defects in ATZ-treated rats. Testicular sperm number, daily sperm production, and sperm viability remained unchanged in all treatment groups. Administration of MYR abated ATZ-mediated depletion in antioxidant status, an increase in myeloperoxidase activity, nitric oxide, hydrogen peroxide, malondialdehyde levels, and reactive oxygen and nitrogen species, as well as the histological lesions in the hypothalamus, epididymis, and testes of treated animals. All in all, MYR mitigated atrazine-mediated functional changes in the reproductive axis via anti-inflammatory and antioxidant mechanisms in atrazine-exposed rats. Dietary intake of MYR could be a worthy chemoprotective approach against reproductive dysfunction related to ATZ exposure.

Endocrine disruptors in ancient times and Greek mythology: the spring of Salmacis and the curse of Hermaphroditus.

According to Greek mythology, the spring waters of Salmacis (or Salmakis) feminized the god Hermaphroditus (or Hermaphroditos) and transformed his nature from male to half-male and half-female. The mythical properties of these waters are described in the writings of authors and philosophers of the Hellenistic period. It is evident that the spring of Salmacis and lake actually existed (located in Halicarnassus, today Bodrum, Turkey) and are not the product of poetic imagination. Hence, it could be hypothesized that there were certain natural elements in the waters that had a feminizing effect on the male reproductive axis. We now know, in fact, that naturally occurring environmental agents, also known as endocrine disruptors, can affect the endocrine and reproductive function of both males and females. However, since most endocrine disruptors today are manmade products of the modern industrial lifestyle, the presence and effect of naturally occurring disruptors in times preceding the Industrial Revolution are not widely discussed. It is thus against this background that we seek to formulate a differential diagnosis of male feminization attributable to the effect of natural environmental factors in the form of endocrine disruptors that will have existed in environments round the globe since time immemorial. We conclude that if there had been an accumulation of the mycotoxin zearalenone (ZEA) in the waters of Salmacis, chronic exposure to the lake's water could have resulted in the phenotypic changes described in the Salmacis myth.

The Effects of the New Therapeutic Treatments for Diabetes Mellitus on the Male Reproductive Axis.

One of the complications of chronic hyperglycemia and insulin resistance due to type 2 diabetes mellitus (T2DM) on the hypothalamic-pituitary-gonadal axis in men, is the high prevalence of hypogonadotropic hypogonadism, which has been recently defined as functional hypogonadism, characterized by low testosterone associated with inappropriately normal gonadotropin levels. Although the pathophysiology of this hormonal imbalance may be related to several factors, including glycemic control, concomitant sleep apnea, insulin resistance, the main role is determined by the degree of central or visceral obesity and the consequent inflammatory state. Several drugs have been developed to treat T2DM such as glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase 4 inhibitors, and sodium-glucose co-transporter 2 inhibitors. All appear to be effective in ameliorating blood glucose control, by lowering inflammation and body weight, and most seem to reduce the risk of micro- and macrovascular damage as a consequence of uncontrolled diabetes. A few studies have evaluated the impact of these drugs on gonadal function in T2DM patients with hypogonadism, with promising results. This review summarizes the main current knowledge of the effects of these new antidiabetic drugs on the hypothalamus–pituitary–gonadal axis, showing their potential future application in addition to glucose control in dysmetabolic male patients.

The Impact of Endocrine-Disrupting Chemicals in Male Fertility: Focus on the Action of Obesogens.

The current scenario of male infertility is not yet fully elucidated; however, there is increasing evidence that it is associated with the widespread exposure to endocrine-disrupting chemicals (EDCs), and in particular to obesogens. These compounds interfere with hormones involved in the regulation of metabolism and are associated with weight gain, being also able to change the functioning of the male reproductive axis and, consequently, the testicular physiology and metabolism that are pivotal for spermatogenesis. The disruption of these tightly regulated metabolic pathways leads to adverse reproductive outcomes. The permanent exposure to obesogens has raised serious health concerns. Evidence suggests that obesogens are one of the leading causes of the marked decline of male fertility and key players in shaping the future health outcomes not only for those who are directly exposed but also for upcoming generations. In addition to the changes that lead to inefficient functioning of the male gametes, obesogens induce alterations that are “imprinted” on the genes of the male gametes, establishing a link between generations and contributing to the transmission of defects. Unveiling the molecular mechanisms by which obesogens induce toxicity that may end-up in epigenetic modifications is imperative. This review describes and discusses the suggested molecular targets and potential mechanisms for obesogenic–disrupting chemicals and the subsequent effects on male reproductive health.

Factors affecting the production of quality ejaculates from boars

Production of acceptable quality ejaculates in boars is dependent upon the Sertoli cell population established before puberty and how effectively these cells function after sexual maturity. In general, factors affecting Sertoli cell mitosis tend to have a two-fold greater effect on sperm production compared with those affecting spermatogenesis. Birthweight is a reliable indicator of in utero testicular development and prepubertal growth rates are positively correlated with testis size and sperm production after sexual maturity. Colostrum intake and pre-weaning nutrition account for much of the variation associated with quality and quantity of ejaculates and represent opportunities to further enhance lifetime sperm production. Interactions between young boars and humans, shortly after weaning, have important effects on spermatogenesis after sexual maturity and need to be studied further. The seasonal effect on depression in semen quality is the most significant factor affecting production of acceptable quality ejaculates after puberty. Ambient temperatures, greater than those of the thermoneutral zone, have both acute and chronic effects that compromise all aspects of the male reproductive axis. Identification of genes associated with heat-tolerant phenotypes holds promise for addressing this challenge, especially in light of the current trend in global warming. Supplementation of vitamins, minerals and other compounds have positive effects on sperm production during periods in which other stressors, especially heat stress, are present and is an important mitigation strategy. Recent information on housing conditions and boar usage patterns indicate these cause relatively minor changes in sperm production, overall, but for some males can have significant, long-term effects.

Short-term regular moderate exercise improved male hypothalamic-pituitary-gonadal axis function via the reduction of hypothalamic neurokinin B expression in adult rats

Introduction: In the arcuate nucleus, kisspeptin, neurokinin-B and pro-dynorphin (KNDy) neurons control the function of gonadotropin-releasing hormone (GnRH) neurons. Early investigations indicated that exercise with various intensities affects luteinizing hormone (LH) and testosterone (T) in different ways. Meanwhile the molecular mechanisms underlying its function not yet been fully understood. Accordingly, the present study evaluated the role of alterations in the levels of KNDy mRNA upstream of GnRH neurons in conveying the effects of various short-term exercise intensities on the male hypothermic-pituitary-gonadal (HPG) axis. Methods: Twenty-one adult Wistar rats were randomly divided into 3 groups: control, one-month regular moderate exercise (ME) and one-month regular intensive exercise (IE). In ME (22m/min) and IE (35m/min) groups, the rats were treated 5 days a week for 60min each day. Finally, we assessed serum levels of LH and T using the ELIZA technique and KNDy and Gnrh mRNA expression by the real-time PCR method. Results: The results revealed that in ME group the expression of Nkb was reduced and the expression of Gnrh mRNA and the LH and T serum levels were increased. However, intensive exercise did not change the serum levels of LH and T or the relative expression of kiss1, Nkb, Pdyn and Gnrh genes. Conclusion: The results suggested that monthly moderate exercise improved male reproductive axis function, while intensive exercise did not have an adverse effect on the reproductive axis. These various effects on the male HPG axis may be propagated by the change in hypothalamic Nkb gene expression.

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.

Peroxisome proliferator-activated receptor gamma expression along the male genital system and its role in male fertility.

Peroxisome proliferator-activated receptor gamma (PPARγ) acts as a ligand activated transcription factor and regulates processes, such as energy homeostasis, cell proliferation and differentiation. PPARγ binds to DNA as a heterodimer with retinoid X receptor and it is activated by polyunsaturated fatty acids and fatty acid derivatives, such as prostaglandins. In addition, the insulin-sensitizing thiazolidinediones, such as rosiglitazone, are potent and specific activators of PPARγ. PPARγ is present along the hypothalamic-pituitary-testis axis and in the testis, where low levels in Leydig cells and higher levels in Sertoli cells as well as in germ cells have been found. High amounts of PPARγ were reported in the normal epididymis and in the prostate, but the receptor was almost undetectable in the seminal vesicles. Interestingly, in the human and in pig, PPARγ protein is highly expressed in ejaculated spermatozoa, suggesting a possible role of PPARγ signaling in the regulation of sperm biology. This implies that both natural and synthetic PPARγ ligands may act directly on sperm improving its performance. Given the close link between energy balance and reproduction, activation of PPARγ may have promising metabolic implications in male reproductive functions. In this review, we first describe PPARγ expression in different compartments of the male reproductive axis. Subsequently, we discuss the role of PPARγ in both physiological and several pathological conditions related to the male fertility.

Effects of leptin on HPG axis and reproductive function in male rat in simulated altitude of 5500 m hypoxia environment

High altitude hypobaric hypoxia environment impairs male’s reproductive function. Leptin is an adipose tissue-derived hormone which regulates body weight homeostasis. Its receptor (LepR) has been found in all levels of male reproductive axis, indicating that it can affect male reproductive system in a direct or (and) indirect way. However, the role of leptin signaling in hypobaric hypoxia induced male reproductive dysfunction remains to be elucidated. In this study, we investigated the changes of leptin levels in male SD rats in stimulated altitude of 5500 m hypobaric hypoxia environment and their effects on the hypothalamus-pituitary-gonad axis (HPG axis). A hypoxia animal model was established using a hypobaric hypoxia chamber. Rats were divided randomly into 1, 7, 14, 28-day hypoxia group, recovery group (14 days hypoxia+14 days normoxia) and their control groups. Hypoxia groups displayed obvious changes of testicular and epididymis index compared to control groups. The total number of sperm and sperm motility rate decreased dramatically, while sperm deformity rate increased in hypoxia groups. The flow cytometry analysis showed that the percentage of haploid in 1-day, 7-day and 28-day hypoxia groups increased while the proportion of diploid decreased in 14-day and 28-day hypoxia group. TUNEL staining showed that the testis cells apoptosis index (AI) of hypoxia groups increased significantly, and the apoptosis of cells mainly focus on spermatogonia and spermatocytes. The expression of GnRH in hypothalamus decreased dramatically under hypoxia condition, accompanied with the reduction of serum testosterone (T) level in 1-day and 28-day hypoxia groups and free-testosterone level (FT) in 1-day and 14-day hypoxia groups. Importantly, ELISA analysis showed that serum leptin level decreased in 7-day hypoxia groups and acylated-ghrelin, gastrin also changed, accompanying with reduction of LepR in hypothalamus in hypoxia groups. Immunohistochemical staining exhibited increased leptin and LepR in testis under hypobaric hypoxia conditions. Our results suggested that simulated high altitude hypobaric hypoxia environment decreased male reproductive function, depressed HPG axis activity and altered the serum concentration of hormones related to food intake in adult male rats. Additionally, hypobaric hypoxia induced the leptin-LepR expression in adult male rats’ testis, suggesting leptin-LepR signaling may mediate hypoxia-induced impairment in male rats’ reproductive system.

The influence of maternal androgen excess on the male reproductive axis

Prenatal androgen excess is suspected to contribute to the development of polycystic ovary syndrome (PCOS) in women. Evidence from preclinical female animal models links maternal androgen excess with the development of PCOS-like features and associated alterations in the neuronal network regulating the reproductive axis. There is some evidence suggesting that maternal androgen excess leads to similar reproductive axis disruptions in men, despite the critical role that androgens play in normal sexual differentiation. Here, the specific impact of maternal androgen excess on the male hypothalamic-pituitary-gonadal axis was investigated using a prenatal androgenization protocol in mice shown to model PCOS-like features in females. Reproductive phenotyping of prenatally androgenised male (PNAM) mice revealed no discernible impact of maternal androgen excess at any level of the reproductive axis. Luteinising hormone pulse characteristics, daily sperm production, plasma testosterone and anti-Müllerian hormone levels were not different in the male offspring of dams administered dihydrotestosterone (DHT) during late gestation compared to controls. Androgen receptor expression was quantified through the hypothalamus and identified as unchanged. Confocal imaging of gonadotropin-releasing hormone (GnRH) neurons revealed that in contrast with prenatally androgenised female mice, PNAM mice exhibited no differences in the density of putative GABAergic innervation compared to controls. These data indicate that a maternal androgen environment capable of inducing reproductive dysfunction in female offspring has no evident impact on the reproductive axis of male littermates in adulthood.

Potential inhibitory effect of swimming exercise on the Kisspeptin–GnRH signaling pathway in male rats

Aerobic exercises are considered as an effective method of improving several undesirable health outcomes; however, their implications in the male reproductive axis have remained controversial. The present study evaluated the impact of physical exercise on the male reproductive system in rats and investigated the potential central and peripheral mechanisms involved in it. Twenty male Sprague–Dawley rats were randomly divided into control and exercise groups, with 10 rats per group. The rats were subjected to a swimming exercise for 60 min/day for five days a week and the protocol was followed for six constitutive weeks. We found that the swimming exercise significantly decreased the testicular weight and the testicular somatic index. Furthermore, there was a marked reduction in several sperm characteristics, including sperm count, motility, morphology, and viability in the exercised rats. The serum levels of reproductive hormones, i.e., testosterone (T), luteinizing hormone (LH), and follicle stimulating hormone (FSH) were significantly decreased. A histological examination of testes and epididymis revealed defective spermatogenesis. Molecular analysis revealed the downregulation of the expression of mRNAs of the hypothalamic kisspeptin (Kiss1), Kiss1 receptor (Kiss1r), gonadotropin-releasing hormone (GnRH1), GnRH1 receptor (GnRHr), and testicular Kiss1r along with an upregulation in the gene expression of GnRHr in the pituitary. We also observed a significant reduction in the activity and the expression of mRNAs of testicular superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) and a marked elevation in the levelsof malondialdehyde (MDA). These findings implied that chronic swimming exercise suppressed the Kisspeptin–GnRH signaling pathway, consequently reducing the production of male reproductive hormones. A simultaneous increase in the oxidative stress could contribute to exercise-induced inhibition of male reproductive functions. To conclude, an appropriate training program is important to maximize the benefits and minimize the side effects of physical exercises on the male reproductive system.

The Kiss2/GPR54 system stimulates the reproductive axis in male black porgy, Acanthopagrus schlegelii

Although it is well established that the Kiss1/GPR54 system stimulates the reproductive axis in mammals, its functional roles, especially in male reproduction of non-mammalian species, is less clear. In this study, we have isolated the full-length kiss2 and gpr54 cDNAs from black porgy (Acanthopagrus schlegelii). The Kiss2 precursor expressed from kiss2 comprises 124 amino acids and contains a highly conserved 10-amino acid sequence, Kiss2-10 (FNFNPFGLRF). GPR54 comprises 375 amino acid residues and contains distinct characteristics of G protein-coupled receptors. Real-time PCR analysis indicated that kiss2 and gpr54 were expressed highly in the brain regions. Moreover, intraperitoneal injection of porgy Kiss2-10 could stimulate genes expression of the gpr54, gnrh1, gnrh3, fshβ, lhβ, p450c17, star, and ar, and the serum testerone level in male black porgy. Our findings demonstrate that the Kisspeptin stimulates the male reproductive axis in black porgy.

Association of circulatory Kisspeptin levels and hormonal interplay with male infertility: A cross-sectional study in Karachi, Pakistan.

To determine the impact of Kisspeptin on male reproductive axis in a selected urban population. The cross-sectional study was conducted at the Sindh Institute of Reproductive Medicine in collaboration with Aga Khan University, Karachi, from July, 2017, to February, 2018, and comprised infertile males with abnormal sperm parameters who were placed in Group A and fertile males with normal sperm parameters placed in Group B. Serum samples were estimated for Kisspeptin, follicle stimulating hormone, luteinizing hormone, testosterone and sex hormone-binding globulin using enzyme-linked immunosorbent assay. Data was analysed using SPSS 22. Of the 313 male subjects, 178(57%) were in Group A and 135(43%) in Group B. Median Kisspeptin levels were higher among fertile males compared to infertile males (p<0.001). Mean follicle stimulating hormone, luteinizing hormone and testosterone values were higher among the fertile males (p<0.001). There was significant interaction between follicle stimulating hormone and testosterone (p<0.1). Fertility in males depended on optimal secretion of Kisspeptin which exert edits effect on hypothalamic pituitary gonadal axis to increase male reproductive hormone production.

Stress rapidly suppresses in vivo LH pulses and increases activation of RFRP-3 neurons in male mice

Restraint stress is a psychosocial stressor that suppresses reproductive status, including LH pulsatile secretion, but the neuroendocrine mechanisms underlying this inhibition remains unclear. Reproductive neural populations upstream of gonadotropin-releasing hormone (GnRH) neurons, such as kisspeptin, neurokinin B and RFRP-3 (GnIH) neurons, are possible targets for psychosocial stress to inhibit LH pulses, but this has not been well examined, especially in mice in which prior technical limitations prevented assessment of in vivo LH pulse secretion dynamics. Here, we examined whether one-time acute restraint stress alters in vivo LH pulsatility and reproductive neural populations in male mice, and what the time-course is for such alterations. We found that endogenous LH pulses in castrated male mice are robustly and rapidly suppressed by one-time, acute restraint stress, with suppression observed as quickly as 12–18 min. This rapid LH suppression parallels with increased in vivo corticosterone levels within 15 min of restraint stress. Although Kiss1, Tac2 and Rfrp gene expression in the hypothalamus did not significantly change after 90 or 180 min restraint stress, arcuate Kiss1 neural activation was significantly decreased after 180 min. Interestingly, hypothalamic Rfrp neuronal activation was strongly increased at early times after restraint stress initiation, but was attenuated to levels lower than controls by 180 min of restraint stress. Thus, the male neuroendocrine reproductive axis is quite sensitive to short-term stress exposure, with significantly decreased pulsatile LH secretion and increased hypothalamic Rfrp neuronal activation occurring rapidly, within minutes, and decreased Kiss1 neuronal activation also occurring after longer stress durations.

Various responses of male pituitary–gonadal axis to different intensities of long-term exercise: Role of expression of KNDY-related genes

The essential role of regular physical activity has been emphasized for maintaining a healthy life. However, unfortunately, during the last few decades, the lifestyle of people has led to a decrease in physical activity. Research studies have shown that exercise of different intensities is applied on reproductive performance indices, luteinizing hormone (LH) and testosterone (T), with different effects. Nevertheless, the molecular and cellular mechanisms underlying its function are not completely understood. Therefore, this study aimed to evaluate the role of kisspeptin, neurokinin-B and pro-dynorphin (KNDY) gene-expression changes located in the upstream of GnRH neurons in transferring the effects of different long-term exercise intensities on male reproductive axis. Twenty-one adult Wistar rats were randomly divided into control, 6-month regular moderate exercise (RME-6) and 6-month regular intensive exercise (RIE-6). In moderate and intensive exercise groups, rats were treated 5 days a week for 60 min, at 22 and 35 m/min, respectively. Finally, the hypothalamic arcuate nucleus was isolated and the relative gene expression of kisspeptin (Kiss1), neurokinin-B (Nkb), pro-dynorphin (Pdyn) and gonadotropin-releasing hormone (Gnrh) genes were measured by realtime polymerase chain reaction method. The results showed that RIE-6 treatment decreased Gnrh and increased Pdyn mRNA levels in the arcuate nucleus. Furthermore, although RME-6 treatment decreased Nkb and increased Pdyn mRNA levels, the Gnrh mRNAwas not affected. Regarding the Gnrh mRNA levels and serum concentrations of reproductive indices (LH and T), moderate exercise did not impose harmful effects on the hypothalamic-pituitary-gonadal axis than intensive exercise. The different impacts of diverse long-term exercise intensities on the male pituitary-gonadal axis maybe relay by the various changes in hypothalamic Nkb and Pdyn gene expressions.