Intratesticular Testosterone Concentrations Research Articles

Contraceptive efficacy: Determining the threshold for effective suppression based on sperm concentration, motility, and morphology.

Human spermatogenesis is a complex process that transforms spermatogonial stem cells through mitosis and meiosis to spermatozoa. Testosterone is the key regulator of the terminal stages of meiosis, adherence of spermatids to Sertoli cells, and spermiation. Follicle-stimulating hormone (FSH) may be required for early spermatogenesis and is important for maintaining normal spermatogenesis in men. Hormonal contraception suppresses FSH, luteinizing hormone, and intratesticular testosterone concentration, resulting in marked suppression of sperm output. Clinical trials using testosterone alone or testosterone plus progestin demonstrate that sustained suppression of sperm concentration to ≤1 million/mL is sufficient to prevent pregnancy in the female partner. New agents that target spermatogenesis could use this as a target for contraceptive efficacy while others that block sperm function or transport may require a lower threshold. When sperm concentrations are suppressed to such low levels, measurement of sperm motility and morphology is technically difficult and unnecessary. With current data from fertile and infertile men, it is not possible to establish a lower limit of sperm motility or percent normal morphology that equates to the prevention of conception. New compounds that decrease sperm motility or alter sperm morphology may need to demonstrate a complete absence of sperm motility or altered morphology in all spermatozoa in the ejaculate. Sperm function tests may be useful depending on the mechanism of action of each new compound. Monitoring of sperm surrogate markers to ensure effective contraception relies on laboratories experienced in semen analyses. The development of at-home tests to assess sperm parameters has progressed rapidly. Some tests have been assessed in clinical trials and approved by regulatory agencies for at-home use for fertility assessment. However, caution must be exercised in using these tests as many have not been rigorously validated against semen parameters measured in laboratories by trained technologists using standardized tests defined in the World Health Organization Semen Manual.

Hormonal male contraception.

Male contraception with exogenously administered hormones suppresses both luteinizing hormone and follicle stimulating hormone leading to low intratesticular testosterone concentration. This results in reversible suppression of spermatogenesis and marked decrease in sperm output in the ejaculate and preventing pregnancy in the female partner. Studies of testosterone administered alone or in combination of another gonadotropin suppressive agent such as a progestin or gonadotropin releasing hormone (GnRH) analog showed decisively that the exogenous hormone administrations are effective in suppressing sperm output with few adverse events that are not anticipated. In contraceptive efficacy studies, testosterone alone or combined with a progestin are as effective in preventing pregnancies as female contraceptive methods. Hormone combinations for male contraception are in late-phase clinical trials and hold the promise of being the new, reversible contraception method for men in over half a century. Lessons learned from the male hormonal contraceptive development pave the way for new targeted approached to regulate male fertility.

Intratesticular Testosterone and Its Precursors among Azoospermic Men: A Pilot Study.

The study aimed to comprehensively analyze testosterone and precursor concentrations in the testicular interstitial fluid (TIF) of men with azoospermia, exploring their significance in the testicular microenvironment and their correlation with testicular sperm retrieval outcomes. We analyzed 37 TIF samples, including 5 from men with obstructive azoospermia (OA) and 32 from men with non-obstructive azoospermia (NOA). Liquid chromatography with tandem mass spectrometry quantified testosterone and precursor levels. Comparative assessments of the outcomes of testicular sperm retrieval were performed between the OA and NOA groups as well as among men with NOA. Men with NOA who had not undergone hormone treatment exhibited significantly higher intratesticular concentrations of testosterone (median 1,528.1 vs. 207.5 ng/mL), androstenedione (median 10.6 vs. 1.9 ng/mL), and 17-OH progesterone (median 13.0 vs. 1.8 ng/mL) than men diagnosed with OA. Notably, in the subgroup of patients with NOA subjected to medical treatment, men with successful sperm retrieval had significantly reduced levels of androstenedione (median androstenedione 5.7 vs. 18.5 ng/mL, p=0.004). Upon a more detailed analysis of these men who underwent hormone manipulation treatment, the testosterone/androstenedione ratio (indicative of HSD17B3 enzyme activity) was markedly increased in men with successful sperm retrieval (median: 365.8 vs. 165.0, p=0.008) compared with individuals with NOA who had unsuccessful sperm recovery. Furthermore, within the subset of men with NOA who did not undergo medical treatment before microdissection testicular sperm extraction but achieved successful sperm retrieval, the ratio of 17-OH progesterone/progesterone (indicative of CYP17A1 activity) was substantially higher. The study suggests distinct testosterone biosynthesis pathways in men with compromised spermatogenesis and those with normal spermatogenesis. Among NOA men with successful retrieval after hormone optimization therapy, there was decreased androstenedione and increased HSD17B3 enzyme activity. These findings have diagnostic and therapeutic implications for the future.

Role of serotonin, estrogen, and TNF-α in the paroxetine-impaired steroidogenesis and testicular macrophages polarization.

Paroxetine, a selective serotonin reuptake inhibitor (SSRI) antidepressant, has caused male sexual dysfunction; however, the paroxetine mechanisms of action in testes are still unclear. Paroxetine serotonergic effects in testes were evaluated, focusing on steroidogenesis and the correlation between macrophages population and possible TNF-α-derived oxidative stress. We also verified whether the changes are reversible following treatment interruption. Adult rats received paroxetine (PG35 and PG65) or tap water (CG) for 35 days. PG65 was maintained without treatment for 30 more days. Intratesticular testosterone (IT), nitrite, and malondialdehyde concentrations were measured. To confirm serotonergic and estrogenic effects, Htr1b and Esr1 expressions were analyzed. The daily sperm production (DSP), frequency of abnormal seminiferous tubules (ST), SC number, ST area, and Leydig cells nuclear area (LCnu) were evaluated. TUNEL+ germ cells, M1 (CD68+ ), and M2 (Perls+ ) macrophages were quantified. 17β-HSD7, CYP19A1, NDRG2, oxytocin, TNF-α, and iNOS were evaluated by immunoreactions. Oxytocin and NDRG2 protein levels as well as Tnfa mRNA expression were also analyzed. The Htr1b downregulation in testes confirmed the paroxetine serotonergic effect. The testicular sections showed abnormal ST frequency, ST atrophy and reduction of DSP, LCnu, SC number and Perls+ macrophages. TUNEL+ germ cells and LC were associated with strong NDRG2 immunoexpression. Paroxetine reduced IT levels and 17β-HSD7 immunoexpression in parallel to increased CYP19A1, oxytocin, TNF-α and iNOS. Esr1 and Tnfa overexpression and increased number of CD68+ macrophages were also observed together with high nitrite and malondialdehyde levels. Most parameters were not recovered in PG65. Paroxetine serotonergic effect impairs LC steroidogenesis, via aromatization, increasing estrogen/testosterone ratio, which in turn upregulate NDRG2, promoting apoptosis, and impairing sperm production. Serotonin-estrogen pathways may be responsible for M2/M1 polarization, Tnfa upregulation, and induction of oxidative stress. The unrecovered testicular changes after treatment discontinuation are due to persistent paroxetine serotonin/estrogen effects.

Apelin receptor antagonist (ML221) treatment has a stimulatory effect on the testicular proliferation, antioxidants system and steroidogenesis in adult mice

The expression of apelin and its receptor (APJ) has been shown in the hypothalamus-pituitary-testicular axis. It has also been suggested apelin and APJ are neuropeptide factors. The presence of apelin and APJ in the seminiferous tubules and interstitium might be predicted to act as a local regulator of testicular activity, although the function is not well known in the mice testis. In the present study, we have investigated the effects of APJ, antagonist, ML221 on the gonadotropin levels, testicular steroidogenesis, proliferation, apoptosis and antioxidant system. Our results showed that inhibition of APJ by ML221 increased the sperm concentration, circulating testosterone, FSH, LH levels and intra-testicular testosterone concentration. Furthermore, ML221 treatment stimulates the germ cell proliferation and antioxidant system in the testis. The expression of BCL2, AR was up-regulated whereas, the expression of BAX and active caspase3 was down-regulated after ML221 treatment. Immunohistocehmical analysis of AR also showed increase abundance in the spermatogonia, primary spermatocytes and Leydig cells of 150 μg/kg dose group. These findings suggest that in adult testis, the apelin system might have an inhibitory role in germ cell proliferation and a stimulatory role in apoptosis. It might also be suggested that the apelin system could be involved in the disposal mechanism for damaged germ cells during spermatogenesis via the down-regulation of AR.

The Roles of Luteinizing Hormone, Follicle-Stimulating Hormone and Testosterone in Spermatogenesis and Folliculogenesis Revisited.

Spermatogenesis and folliculogenesis involve cell–cell interactions and gene expression orchestrated by luteinizing hormone (LH) and follicle-stimulating hormone (FSH). FSH regulates the proliferation and maturation of germ cells independently and in combination with LH. In humans, the requirement for high intratesticular testosterone (T) concentration in spermatogenesis remains both a dogma and an enigma, as it greatly exceeds the requirement for androgen receptor (AR) activation. Several data have challenged this dogma. Here we report our findings on a man with mutant LH beta subunit (LHβ) that markedly reduced T production to 1–2% of normal., but despite this minimal LH stimulation, T production by scarce mature Leydig cells was sufficient to initiate and maintain complete spermatogenesis. Also, in the LH receptor (LHR) knockout (LuRKO) mice, low-dose T supplementation was able to maintain spermatogenesis. In addition, in antiandrogen-treated LuRKO mice, devoid of T action, the transgenic expression of a constitutively activating follicle stimulating hormone receptor (FSHR) mutant was able to rescue spermatogenesis and fertility. Based on rodent models, it is believed that gonadotropin-dependent follicular growth begins at the antral stage, but models of FSHR inactivation in women contradict this claim. The complete loss of FSHR function results in the complete early blockage of folliculogenesis at the primary stage, with a high density of follicles of the prepubertal type. These results should prompt the reassessment of the role of gonadotropins in spermatogenesis, folliculogenesis and therapeutic applications in human hypogonadism and infertility.

Atrazine impairs testicular function in BalB/c mice by affecting Leydig cells

Several studies have reported the effects of atrazine on the gonads of many experimental models. However, the short-term effects of in vivo exposure to atrazine on the testes of mice are not well clarified. Here we reported that adult BalB/c mice exposed to atrazine (50 mg kg−1 body weight) by gavage for three consecutive days have reduced numbers of 3β-hydroxysteroid dehydrogenase positive Leydig cells (LCs), associated with increased in situ cell death fluorescence and caspase-3 immuno-expression in the testes. Consequently, immunostaining for cell cycle gene regulators showed increased expressions of p45, accompanied with increased expressions of cyclin D2 and E2. Histological observations of the gonads showed reduced number of germ cells in particular areas, sloughed seminiferous epithelium, presence of giant apoptotic cells close to the seminiferous tubule lumen and in the epididymal lumen along with low numbers of Leydig cells in the testicular interstitial areas. Similarly, LCs isolated from the testes of BalB/c mice that were exposed to atrazine (0.5, 25, 50 mg kg−1 body weight) in the same manner as in the first experiment presented dose-dependent increased caspase-3 activity, decreased cell viability, intratesticular and serum testosterone concentrations and LCs testosterone secretion. In summary, atrazine appears to directly decrease the number of testosterone secreting LCs in mice through apoptosis.

Slit/Robo signaling regulates Leydig cell steroidogenesis

BackgroundFirst identified as a regulator of neuronal axon guidance, Slit/Robo signaling has since been implicated in additional physiologic and pathologic processes, such as angiogenesis, organogenesis and cancer progression. However, its roles in the regulation of testis function have been little explored.MethodsImmunohistochemistry and RT-qPCR analyses were performed to detect the expression of Slit/Robo signaling effectors in the adult mouse testis. To identify the roles and mechanisms of Slit/Robo signaling in the regulation of steroidogenesis, RT-qPCR, immunoblotting and hormone measurements were carried out using Leydig cells (primary cultures and the MA10 cell line) treated with exogenous SLIT ligands, and testes from Robo1-null mice.ResultsSlit1, -2 and -3 and Robo1 and -2 expression was detected in the adult mouse testis, particularly in Leydig cells. In vitro treatment of Leydig cells with exogenous SLIT ligands led to a decrease in the expression of the steroidogenic genes Star, Cyp11a1, and Cyp17a1. SLIT2 treatment decreased the phosphorylation of the key steroidogenic gene regulator CREB, possibly in part by suppressing AKT activity. Furthermore, SLIT2 treatment reduced the responsiveness of MA10 cells to luteinizing hormone by decreasing the expression of Lhcgr. Consistent with these in vitro results, an increase in testicular Star mRNA levels and intra-testicular testosterone concentrations were found in Robo1-null mice. Finally, we showed that the expression of the Slit and Robo genes in Leydig cells is enhanced by testosterone treatment in vitro, by an AR-independent mechanism.ConclusionTaken together, these results suggest that Slit/Robo signaling represents a novel mechanism that regulates Leydig cell steroidogenesis. It may act in an autocrine/paracrine manner to mediate negative feedback by testosterone on its own synthesis.4VdBjKyUK_zz54UEEeomAMVideo

Di-n-butyl phthalate diminishes testicular steroidogenesis by blocking the hypothalamic-pituitary-testicular axis: relationship with germ cell apoptosis in Japanese quail.

Although di-n-butyl phthalate (DBP) induces germ cell apoptosis, the underlying mechanism is not yet clear in quail. In this study, prepubertal quails were given a single dose of 500mg kg-1 DBP by gavage and were then killed 3, 6 and 24h after treatment. There was a significant reduction in intratesticular testosterone (ITT) concentrations and testicular steroidogenic enzyme mRNA expression and a significant increase in germ cell apoptosis in DBP-treated compared with control quails at all time points. Maximum apoptosis was detected 6h after treatment and the maximum reduction in testosterone concentrations was at 3h. To investigate whether DBP suppressed testicular steroidogenesis by affecting the hypothalamic-pituitary-testicular axis, we analysed pituitary LH subunit β (Lhb) mRNA expression and serum LH concentrations. At all time points, pituitary Lhb expression and serum LH concentrations were significantly decreased following DBP treatment. The present observations suggest the possibility that DBP blocked LH secretion from the hypothalamus and/or pituitary, thereby decreasing LH stimulation of Leydig cells and reducing ITT concentrations. DBP-induced decreases in ITT concentrations may cause changes to the physical structure of Sertoli cells, which, in turn, may induce germ cell apoptosis.

Oxidative Stress Disrupted Prepubertal Rat Testicular Development after Xenotransplantation.

In the past two decades, testicular tissue grafting and xenografting have been well established, with the production of fertilization-competent sperm in some studies. However, few studies have been carried out to observe the development of grafted prepubertal testicular tissue of rats and compare the biological differences between in situ testis and grafted testis. In this study, we established the prepubertal testicular tissue xenografting model using a 22-day-old rat and evaluated certain parameters, including testicular histology, testosterone production, and ultrastructure of the grafted testes. We also assessed gene expression of cell proliferation markers, testicular cell markers, and antioxidative defense system. Our results showed that 47 days after transplantation, intratesticular testosterone concentration was not significantly altered; however, cell proliferation, spermatogenesis, and Sertoli cell markers in the transplanted testes were significantly disrupted compared with the control group, accompanied by aggravated apoptosis and oxidative damage. Moreover, the transplanted testes showed smaller tubular diameter and disrupted spermatogenic epithelium with apparent vacuoles, distorted and degenerated germ cells with obscure nuclear margin, and no spermatids in the center of the tubules. Although testis xenografting has been extensively tested and attained great achievement in other species, the prepubertal rat testicular tissue xenografting to immunodeficient mice exhibited obvious spermatogenesis arrest and oxidative damage. The protocol still needs further optimization, and there are still some unknown factors in prepubertal rat testes transplantation.

The Role of Androgen Signaling in Male Sexual Development at Puberty.

Puberty is characterized by major changes in the anatomy and function of reproductive organs. Androgen activity is low before puberty, but during pubertal development, the testes resume the production of androgens. Major physiological changes occur in the testicular cell compartments in response to the increase in intratesticular testosterone concentrations and androgen receptor expression. Androgen activity also impacts on the internal and external genitalia. In target cells, androgens signal through a classical and a nonclassical pathway. This review addresses the most recent advances in the knowledge of the role of androgen signaling in postnatal male sexual development, with a special emphasis on human puberty.

Serum 17-Hydroxyprogesterone is a Potential Biomarker for Evaluating Intratesticular Testosterone.

Intratesticular testosterone is essential for spermatogenesis and can only be reliably measured with invasive testicular sampling. Previous studies have demonstrated good correlation between intratesticular testosterone and serum 17-hydroxyprogesterone (17-OHP) in men treated with human chorionic gonadotropin. Based on this observation we hypothesized that we can use serum 17-OHP as a serum biomarker for evaluating intratesticular testosterone in men receiving medications that alter serum testosterone. Initially, we conducted a cross-sectional analysis of men with a single serum 17-OHP evaluation from July 2018 to March 2019. We followed this with a prospective analysis from July 2018 to October 2019 with evaluation of 140 men including fertile controls, and those receiving treatments that alter serum testosterone at baseline and after 3 months of therapy. According to the data distribution, we reported the median and interquartile ranges, and used the Mann Whitney U or Wilcoxon tests. In the initial cross-sectional analysis of 93 men, a total of 30 men received treatments that increase or maintain intratesticular testosterone concentrations, such as clomiphene citrate and/or human chorionic gonadotropin; 21 men received treatments that suppress intratesticular testosterone concentrations (various exogenous testosterone replacement therapy formulations) and 42 fertile men with normal serum testosterone (greater than 300 ng/dl) were used as control. We demonstrated that serum testosterone levels were within normal range among men receiving the various therapies. In contrast, we found that serum 17-OHP was undetectable in men who received exogenous testosterone replacement therapy, as opposed to men receiving human chorionic gonadotropin and/or clomiphene citrate or fertile controls (p <0.05). In the prospective evaluation that ensued, 17-OHP values decreased in the 21 men who received testosterone replacement therapy (47.5 [21-70] to 13.5 [10-23] ng/dl, p <0.05). Conversely, 17-OHP increased in the 55 men who received human chorionic gonadotropin and/or clomiphene citrate when compared to their baseline levels (42 [24-72] to 88 [61-135] ng/dl, p <0.05). Serum 17-OHP appears to be a reliable serum marker for intratesticular testosterone levels and could potentially be used to titrate or change medications that alter intratesticular testosterone.

Continuing the search for a hormonal male contraceptive.

This chapter discusses the mechanisms of action of hormonal male contraception, which suppresses the hypothalamic-pituitary-testis axis. When the intratesticular concentration of testosterone is subsequently suppressed to adequately low concentrations, spermatogenesis is arrested. Androgens are a necessary hormonal male contraceptive component because they not only suppress the hypothalamic-pituitary-testis axis, but also provide the male hormone necessary to maintain peripheral androgen functions. Past studies using testosterone alone and testosterone combined with progestins demonstrated contraceptive efficacy in the female partner at rates similar to combined hormonal female methods. Newer hormonal male contraceptive formulations and the alternative routes of administration are discussed, along with potential barriers, challenges, and opportunities for hormonal male contraceptive development. Novel methods that are safe, effective, reversible, user-friendly, and coitus-independent are intrinsic to equitably meet the various needs and limitations of an increasingly diverse population.

Glyphosate-based herbicide exposure during pregnancy and lactation malprograms the male reproductive morphofunction in F1 offspring.

One of the most consumed pesticides in the world is glyphosate, the active ingredient in the herbicide ROUNDUP®. Studies demonstrate that glyphosate can act as an endocrine disruptor and that exposure to this substance at critical periods in the developmental period may program the fetus to induce reproductive damage in adulthood. Our hypothesis is that maternal exposure to glyphosate during pregnancy and lactation in mice will affect the development of male reproductive organs, impairing male fertility during adult life. Female mice consumed 0.5% glyphosate-ROUNDUP® in their drinking water [glyphosate-based herbicide (GBH) group] or filtered water [control (CTRL) group] from the fourth day of pregnancy until the end of the lactation period. Male F1 offspring were designated, according to their mother's treatment, as CTRL-F1 and GBH-F1. Female mice that drank glyphosate displayed reduced body weight (BW) gain during gestation, but no alterations in litter size. Although GBH male F1 offspring did not exhibit modifications in BW, they demonstrated delayed testicular descent. Furthermore, at PND150, GBH-F1 mice presented a lower number of spermatozoa in the cauda epididymis and reduced epithelial height of the seminiferous epithelium. Notably, intratesticular testosterone concentrations were enhanced in GBH-F1 mice; we show that it is an effect associated with increased plasma and pituitary concentrations of luteinizing hormone. Therefore, data indicate that maternal exposure to glyphosate-ROUNDUP® during pregnancy and lactation may lead to decreased spermatogenesis and disruptions in hypothalamus-pituitary-testicular axis regulation in F1 offspring.

Toxicological effects of furan on the reproductive system of male rats: An “in vitro” and “in vivo"-based endocrinological and spermatogonial study

Furan is a colorless toxic chemical produced in various food items during heat processing and in chemical industries. Both in vitro and in vivo studies have reported that it induces oxidative stress and endocrine disruption; however, limited data are available regarding the effects of furan on the reproduction of mammals. In the present study, an in vitro experiment was designed to investigate the direct effects of furan exposure on oxidative stress and testosterone concentration in rat testicular tissue. Furan not only generated high oxidative stress but also decreased antioxidant enzyme activity in the testicular tissue. On the basis of in vitro study results, an in vivo sub-chronic exposure study was performed. Male rats were orally exposed to different concentrations of furan (0, 5, 10, 20, and 40 mg kg−1). An increase (P < 0.05) of reactive oxygen species (ROS) and of the lipid profile (cholesterol, triglycerides, and LDL) in higher dose treatment groups of furan was observed, while total protein content and antioxidant enzyme activity were considerably decreased after furan exposure. Also, plasma and intratesticular testosterone concentrations were reduced in high-dose treatment groups. Sperm parameters such as sperm viability, sperm count, and sperm motility showed a decrease (P < 0.05) in a dose-dependent manner. Histopathological findings revealed significant alterations in testis and epididymis tissues. These results confirm that furan can induce toxic effects on the reproductive system of male rats.

Dietary fluted pumpkin seeds induce reversible oligospermia and androgen insufficiency in adult rats

ABSTRACTSome components of the human diets are believed to be promising male contraceptive agents. The present study examined the antispermatogenic efficacy, reversibility and toxicity of fluted pumpkin seed-supplemented diet (DFPS) in adult male Wistar rats. Adult rats were given DFPS at 2.5, 5 and 10% for 60 days followed by 60 days post-treatment period. The control animals received normal standard rat diet not supplemented with fluted pumpkin seeds. The sperm quality variables, testosterone and follicle-stimulating hormone (FSH), oxidative status of the testis, steroidogenic enzymes and gamma-glutamyl transferase (γ-GT) activities and the histology of the testis were determined to evaluate the anti-fertility activity of fluted pumpkin seeds. Treatment of animals with DFPS at 5% and 10% resulted in decreased serum and intra-testicular testosterone and FSH concentrations. This effect was associated with decreased activity of 17β-hydroxysteroid dehydrogenase (17β-HSD), increased testicular oxidative stress and poor sperm quality in the 10% diet group. After 60 days DFPS post-treatment, intra-testicular 17β-HSD and γ-GT activities, FSH and testosterone levels recovered to control values. Furthermore, poor sperm motility, count, morphology and viability as well as severe loss of spermatogonia and other matured epithelial germ cells and Sertoli cells observed especially in the 10% DFPS-treated animals reverted to nearly control values 60 days after withdrawal of treatment. Dietary fluted pumpkin seeds may selectively act on the epithelial germ cells, possibly mediated via Sertoli cells, leading to oligospermia, oxidative damage and androgen insufficiency. The reversibility of these effects to near normal levels after withdrawal of treatment justifies further consideration of DFPS as it may be an effective and readily reversible agent that meets the required criteria of a male contraceptive agent.Abbreviations: GC-MS: gas-chromatography mass spectrophotometry; MPO: myeloperoxidase; NO: nitric oxide; DFPS: dietary fluted pumpkin seeds; DFPS (REV): DFPS post-treatment; MDA: malondialdehyde; SOD: superoxide dismutase; CAT: catalase; GSH: glutathione; 3β-HSD: 3β-hydroxysteroid dehydrogenase; 17β-HSD: 17β-hydroxysteroid dehydrogenase; NAD: nicotinamide adenine dinucleotide (oxidized); NADH: nicotinamide adenine dinucleotide (reduced); ITT: intra-testicular testosterone; FSH: follicle-stimulating hormone; FPS: fluted pumpkin seeds; NIST: National Institute Standard and Technology; Av: absolute volume; Ac: cross-sectional area; ST: seminiferous tubules; γ-GT: gamma glutamyl transferase.

Role of Follicle-Stimulating Hormone in Spermatogenesis.

Spermatogenesis is a concerted sequence of events during maturation of spermatogonia into spermatozoa. The process involves differential gene-expression and cell-cell interplay regulated by the key endocrine stimuli, i.e., follicle-stimulating hormone (FSH) and luteinizing hormone (LH)-stimulated testosterone. FSH affects independently and in concert with testosterone, the proliferation, maturation and function of the supporting Sertoli cells that produce regulatory signals and nutrients for the maintenance of developing germ cells. Rodents are able to complete spermatogenesis without FSH stimulus, but its deficiency significantly decreases sperm quantity. Men carrying loss-of-function mutation in the gene encoding the ligand (FSHB) or its receptor (FSHR) present, respectively, with azoospermia or suppressed spermatogenesis. Recently, the importance of high intratesticular testosterone concentration for spermatogenesis has been questioned. It was established that it can be completed at minimal intratesticular concentration of the hormone. Furthermore, we recently demonstrated that very robust constitutive FSHR action can rescue spermatogenesis and fertility of mice even when the testosterone stimulus is completely blocked. The clinical relevance of these findings concerns a new strategy of high-dose FSH in treatment of spermatogenic failure.

Ameliorative effects of rutin against cisplatin-induced reproductive toxicity in male rats

BackgroundCisplatin (CP) or cis-diammine dichloroplatinum (II) is a platinum based standard antineoplastic drug which is used against variety of solid tumors and neoplasms. The present study aimed to evaluate the shielding effects of rutin against CP induced testicular toxicity in rats.Methods28 male rats were divided into four groups. First group was given saline orally while second group received intra-peritoneal (i.p) injection of cisplatin (7 mg/kg) on day first and received saline for next 13 days. Third group received i.p injection of cisplatin at day one and treated with rutin (75 mg/kg) orally for next 13 days. Fourth group was treated with rutin orally for 13 days. Animals were sacrificed on 14th day and reproductive organs were analyzed for various parameters.ResultsCisplatin treatment resulted in a significant decrease in daily sperm production, decrease in head length and % DNA in head, reduction of epithelial cell height, tubular diameter, reduction of the number of spermatogonia, spermatocytes and spermatids, increase in the thiobarbituric acid reactive substances (TBARS) and oxidative stress in testicular tissues, and change of the intra-testicular testosterone concentrations. Rutin co-treatment resulted in reversing cisplatin effect on DNA damage, sperm count, histological and biochemical parameters.ConclusionThese results indicated that rutin co-treatment could ameliorate cisplatin-induced reproductive toxicity in male rats.

Correlation between Serum Testosterone Circadian and Intra-Testicular Testosterone Rhythm in a Rat Model

It is well known that in most of the mammals, serum testosterone (T) level has a circadian rhythm. There are few studies discussed whether intra-testicular Testosterone (IT-T) levels have circadian variation. We aimed to compare the serum luteinizing hormone (LH), T and IT-T levels in rats for a 24-h period to examine if IT-T levels have circadian rhythm in Sprague-Dawley rats. Totally 48 male Sprague-Dawley rats were randomly divided into 12 groups, and 4 rats were assigned to each time point from 8 AM to 6 AM in the next morning. After decapitation, the plasma was collected immediately and bilateral testes were retrieved thereafter for further processing for IT-T. We found that serum LH, serum T and IT-T all expressed circadian variations. The serum T and IT-T rhythms were comparable with the highest T level at 2 AM and the lowest level at 2 PM. These two rhythms matched compatibly in every time point. LH rhythm was slightly different from both T and IT-T rhythm with the highest level at 0 AM and the lowest level at 2 PM. Serum T and IT-T concentrations showed a positive correlation, while serum LH has no significant correlation with T or IT-T. We also noticed that in the awaken phase (from 8 PM to 6 AM), the serum T/IT-T ratio remains relatively constant (0.44 ± 0.21 ~ 0.26 ± 0.12%). On the contrary, the serum T/IT-T ratio fluctuated significantly (0.28 ± 0.09 ~ 1.15 ± 0.87%) in the sleeping phase (6 AM to 8 PM). The correlation at awaken phase is much stronger than that at sleeping phase. In summary, we found that IT-T has the same circadian variation with serum T which controlled by the hypothalamic -pituitary-testicular system. IT-T concentration is highly correlated with serum T.

Molecular hydrogen may enhance the production of testosterone hormone in male infertility through hormone signal modulation and redox balance

Since the discovery of molecular hydrogen (H2) as a selective scavenger of free radicals like reactive oxygen species (ROS) and reactive nitrogen species (RNS), numerous studies have proved the potential application of H2 in therapeutic and preventative medicine. Moreover, H2 can regulate the intracellular signal as a signal modulator. However, it is still unclear in cell signaling involved in testosterone hormone production.Male fertility depends on the intra-testicular testosterone concentration, which is produced by the Leydig cell in the seminiferous tubules in testes. Although moderate amounts of ROS are needed for normal sperm function, the higher amounts might decrease testosterone production. High ROS decreases testosterone hormone production by dysregulation of hormonal signal from the hypothalamus to the Leydig cell as a result of redox imbalance. Lower level of testosterone fails to support the Leydig cell for the progression of spermatogenesis. Superoxide anion (O2−), hydroxyl radical (OH) and peroxynitrite (ONOO−) could also attack the DNA, lipid and protein, disrupting sperm structure and function and aggravating the milieu of male fertility and spermatogenesis. H2 regulates intracellular MAPK downstream cAMP signal and Ca2+ signal as a signal modulator to antagonize ROS signaling. Thus H2 can play a role in modulating signals involved in testosterone hormone production to improve male fertility caused by redox imbalance. We therefore hypothesize that molecular hydrogen may enhance testosterone production via cellular redox balance. By this hypothesis, we anticipate that molecular hydrogen may be an effective remedy in male infertility.