Stimulated Testosterone Production Research Articles

Effect of Curcuma longa extract on reproduction function in mice and testosterone production in Leydig cells.

Curcuma longa, best known for its culinary application as the main constituent of curry powder, has shown potential impact on the reproductive system. This study aimed to investigate the efficacy of Curcuma longa extract (CLE) on Kidney-Yang deficiency mice induced by hydrocortisone and the possible roles in testosterone secretion in Leydig cells. We evaluated male sexual behaviour, reproductive organ weight, testosterone levels, and histological tissue changes in hydrocortisone-induced mice. CLE effectively reversed hydrocortisone-induced Kidney-Yang deficiency syndrome by improving sexual behaviour, testis and epididymis weight, testosterone levels and reducing pathological damage. Our invitro study further indicated that CLE stimulated testosterone production via upregulating the mRNA and protein expression of steroidogenic enzymes in Leydig cells. It significantly improved H89-inhibited protein expression of StAR and cAMP-response element-binding (CREB), as well as melatonin-suppressed StAR protein expression. The data obtained from this study suggest that CLE could alleviate Kidney-Yang deficiency symptoms and stimulate testosterone production by upregulating the steroidogenic pathway. This research identifies CLE as a potential nutraceutical option for addressing testosterone deficiency diseases.

Perfluorotetradecanoic acid exposure to adult male rats stimulates corticosterone biosynthesis but inhibits aldosterone production.

Perfluorotetradecanoic acid (PFTeDA) is a novel perfluoroalkyl substance that ubiquitously exists in the environment. However, whether PFTeDA affects adrenal cortex function remains unclear. Male Sprague-Dawley rats (age of 60 days) were daily administered with PFTeDA (0, 1, 5, and 10 mg/kg body weight) through gavage for 28 days. PFTeDA did not change body and adrenal gland weights. PFTeDA markedly elevated serum corticosterone level at 10 mg/kg but lowering serum aldosterone level at this dosage without influencing serum adrenocorticotropic hormone level. PFTeDA thickened zona fasciculata without affecting zona glomerulosa. PFTeDA remarkably upregulated the expression of corticosterone biosynthetic genes (Mc2r, Scarb1, Star, Cyp21, Cyp11b1, and Hsd11b1) and their proteins, whereas downregulating aldosterone biosynthetic enzyme Cyp11b2 and its protein, thereby distinctly altering their serum levels. PFTeDA markedly downregulated the expression of antioxidant genes (Sod1 and Sod2) and their proteins at 10 mg/kg. PFTeDA significantly decreased SIRT1/PGC1α and AMPK signaling while stimulating AKT1/mTOR signaling. Corticosterone significantly inhibited testosterone production by adult Leydig cells at >0.1 μM in vitro; however aldosterone significantly stimulated testosterone production at 0.1 nM. In conclusion, exposure to PFTeDA at male rat adulthood causes corticosterone excess and aldosterone deficiency via SIRT1/PGC1α, AMPK, and AKT1/mTOR signals, which in turn additively leads to testosterone deficiency.

FRI376 Regulation Of Theca Cell Function By Salt-Inducible Kinases

Abstract Disclosure: M. Rodriguez Esquivel: None. E. Hayes: None. O. Lakomy: None. M. Hassan: None. R. Filzen: None. C.O. Stocco: Grant Recipient; Self; NIH R01HD097202. The most common identifiable factors of female infertility are ovulatory disorders. Ovulation is the pinnacle of folliculogenesis, a process that requires an interplay between the oocyte, the granulosa cells, and the theca cells (TCs). TCs are the only source of ovarian androgens. Androgens play vital roles in female fertility acting as substrates for estrogen production in granulosa cells and directly regulating ovarian function via the activation of the androgen receptor. However, abnormally elevated androgen levels reduce fertility in humans and animals, suggesting that a delicate equilibrium exists between the beneficial and harmful effects of androgens in the ovary. Therefore, uncovering novel mechanisms regulating androgen synthesis in TCs is of great significance. The capacity of TCs to synthesize androgens relies on the expression of the rate-limiting enzyme CYP17A1, which converts progestogens into androgens, and its stimulation by the luteinizing hormone (LH). Previously, our group showed that salt-inducible kinases (SIKs) regulate granulosa cell steroidogenesis. Here, we investigated whether SIKs play any role in the regulation of androgen production in TCs. SIK2 and SIK3 were detected by IHC in the TCs of rat ovaries. Western blot confirmed this finding using isolated rat TCs. Next, rat TCs in culture were treated with LH in the presence or absence of HG, a highly specific SIK inhibitor. SIK inhibition enhanced the stimulatory effect of LH on Cyp17a1 mRNA expression. HG alone also increased Cyp17a1 expression to levels higher than those found in the presence of LH. Similarly, HG alone increased testosterone and potentiated LH stimulation of testosterone production. SIK inhibition also enhanced the stimulatory effect of LH on the expression of StAR and Cyp11a1. Concentration-response experiments for the SIK inhibitor in the presence or absence of LH show that SIK inhibition stimulates Cyp17a1 in a concentration-dependent manner from 0.1 to 1 µM. Of note, at 3 µM, HG was less effective in inducing Cyp17a1 than at 1 µM, suggesting that higher concentrations of HG may have alternative unknown effects. Activation of adenyl cyclase with forskolin or emulation of increased intracellular cAMP with dbcAMP stimulated Cyp17a1 an effect that was also enhanced by the inhibition of SIK. Since the main target of cAMP is PKA, we used lentivirus to express constitutively active PKA (caPKA). Overexpression of caPKA was sufficient to stimulate testosterone production, an effect that was significantly augmented by SIK inhibition, suggesting that SIKs regulate factors downstream of PKA. This evidence shows that TCs express SIKs and reveal novel roles for SIKs in the regulation of TC function and androgen production. This information could contribute to uncovering therapeutic targets to treat hyperandrogenic diseases such as PCOS. Presentation: Friday, June 16, 2023

Steroidogenic Effect of Luteinizing Hormone Receptor Agonists and Metformin in Male Rats with Androgenic Deficiency Caused by Diet-Induced Obesity

In obese men, along with metabolic disorders and insulin resistance, testosterone levels are decreased and reproductive system functions are impaired. One of the ways to correct them may be the use of agonists of luteinizing hormone receptor (LHR) and antidiabetic drugs, but the mechanisms of their effect on the hypothalamic-pituitary-gonadal axis have not been studied enough. The aim of the work was to study the effects of long-term MF therapy (5 weeks, 120 mg/kg) and five-day treatment with LHR agonists, such as human chorionic gonadotropin (hCG, 20 IU/rat/day, s.c.) and allosteric agonist TP03 (15 mg/kg/day, i.p.), on the blood testosterone levels and the expression of testicular and pituitary genes in male rats with long-term diet-induced obesity (DIO). TP03 moderately stimulated testosterone production in male rats with DIO without having an inhibitory effect on LHR expression in the testes and only weakly reducing the expression of the LH β-subunit gene in the pituitary gland. After a single administration into DIO-rats, the steroidogenic effect of TP03 was comparable to that in the control group, but after a five-day administration, it was significantly inferior to it. In DIO-rats, the steroidogenic effect of hCG after a single administration was lower than that in the control, but comparable to that after a five-day administration of hCG, and significantly exceeded the corresponding effects of TP03. Unlike TP03, hCG significantly reduced LHR expression in the testes and more pronouncedly inhibited LH expression in the pituitary gland. MF treatment restored the androgenic status without significantly affecting the expression of steroidogenesis genes in the testes. There was no increase in the steroidogenic effects of both LHR agonists in the MF-treated groups. The results obtained indicate the prospects for the use of TP03 and hCG to stimulate testicular steroidogenesis and the effectiveness of MF therapy to normalize testosterone production in DIO, which can be used to correct reproductive disorders in obesity. At the same time, in DIO, the combined use of MF and LHR agonists seems to be inappropriate.

Comprehensive and Quantitative Analysis of the Changes in Proteomic and Phosphoproteomic Profiles during Stimulation and Repression of Steroidogenesis in MA-10 Leydig Cells.

Leydig cells produce testosterone, a hormone essential for male sex differentiation and spermatogenesis. The pituitary hormone, LH, stimulates testosterone production in Leydig cells by increasing the intracellular cAMP levels, which leads to the activation of various kinases and transcription factors, ultimately stimulating the expression of the genes involved in steroidogenesis. The second messenger, cAMP, is subsequently degraded to AMP, and the increase in the intracellular AMP levels activates AMP-dependent protein kinase (AMPK). Activated AMPK potently represses steroidogenesis. Despite the key roles played by the various stimulatory and inhibitory kinases, the proteins phosphorylated by these kinases during steroidogenesis remain poorly characterized. In the present study, we have used a quantitative LC-MS/MS approach, using total and phosphopeptide-enriched proteins to identify the global changes that occur in the proteome and phosphoproteome of MA-10 Leydig cells during both the stimulatory phase (Fsk/cAMP treatment) and inhibitory phase (AICAR-mediated activation of AMPK) of steroidogenesis. The phosphorylation levels of several proteins, including some never before described in Leydig cells, were significantly altered during the stimulation and inhibition of steroidogenesis. Our data also provide new key insights into the finely tuned and dynamic processes that ensure adequate steroid hormone production.

The aphrodisiac potential of β-cyclodextrin–curcumin via stimulating cAMP-PKA pathway in testicular Leydig cells

The water-soluble β-cyclodextrin–curcumin (CDC) is used in pharmaceutical applications and as a natural food colorant. The previous study revealed that curcumin potentially impacted the reproductive system. The present study investigated the possible roles of the CDC in testosterone secretion in Leydig cells and mice. Primary Leydig cells were treated with the CDC to determine their effect on cell proliferation, testosterone levels, the protein and mRNA expression of the transcription factor, and steroidogenic enzymes. Our data showed that CDC stimulated testosterone production via upregulating transcription factor steroidogenic factor-1 (NR5A1), cAMP-response element-binding protein (CREB), and steroidogenic enzymes steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (CYP11A1), 17-alpha-hydroxylase/17,20-lyase (CYP17A1), 3β-/17β-hydroxysteroid dehydrogenase type 1 (3β/17β-HSD, HSD3b1/HSD17b1). CDC could significantly stimulate H89-suppressed StAR and CREB expression but not reverse melatonin-suppressed StAR expression. We further detected the hormonal activity with transgenic yeast, and CDC showed potential androgenic antagonistic activity. Meanwhile, we investigated its aphrodisiac effect on hydrocortisone-induced mice. Exposure to hydrocortisone decreased the mating ability, reproductive organs, and testosterone level and disrupted testicular histology. However, all of these effects were significantly improved by CDC treatment. In conclusion, these results indicated that mechanisms of CDC in stimulating testosterone production involve upregulating the cAMP-PKA pathway.

Novel Potency Assay for MSC Secretome-Based Treatment of Idiopathic Male Infertility Employed Leydig Cells and Revealed Vascular Endothelial Growth Factor as a Promising Potency Marker.

Idiopathic male infertility is a highly prevalent diagnosis in developed countries with no specific treatment options. Although empirical medical treatment is widely used to restore male fertility, its efficacy remains limited and inconclusively proven. Therefore, the development of novel therapeutic approaches in this field is a high-priority task. Since the failure of testicular microenvironment components might be involved in the pathogenesis of idiopathic male infertility, application of mesenchymal stromal cells (MSCs) as well as the MSC secretome is worth considering. Previously, we showed that the intratesticular injection of MSCs or the MSC secretome led to the recovery of spermatogenesis at least through replenishing the testicular microenvironment and its maintenance by MSC-secreted paracrine factors. However, the clinical use of such products has been limited to single trials to date. This may be due to the lack of relevant potency tests reflecting mechanisms of action of the MSC secretome in male infertility models. Based on the presumptive MSC secretome mode of action on the testicular microenvironment, we suggest a novel approach to test the potential efficacy of the MSC secretome for idiopathic male infertility treatment. It represents a potency assay based on evaluation of testosterone production by isolated Leydig cells. We demonstrated that the MSC secretome stimulated testosterone secretion by Leydig cells in vitro. We then hypothesized that among the major factors of the MSC secretome, vascular endothelial growth factor (VEGF) could be responsible for the observed effects, which we confirmed by the revealed correlation between the extent of stimulated testosterone production and VEGF concentration in the MSC secretome. The pilot results obtained from the doxorubicin-induced male infertility murine model also indicate the important impact of VEGF in the MSC secretome’s regenerative effects. Utilizing VEGF as a surrogate factor, a novel approach to study the potency of MSC secretome-based products for idiopathic male infertility treatment is suggested. Further validation is required for its implementation into the biopharmaceutical manufacturing process.

Histomorphometric and oxidative evaluation of the offspring's testis from type 2 diabetic female rats treated with metformin and pentoxifylline.

Type 2 diabetes mellitus (T2D) during pregnancy is characterized by high levels of reactive oxygen species and pro-inflammatory factors in the placenta. Once these reactive species reach the foetus, they trigger physiological adaptations that allow the foetus to survive, but programme the organism to develop metabolic disorders in adulthood. The male reproductive system is highly susceptible to foetal programming. This study aimed to investigate the effects of intrauterine exposure to T2D on testicular histomorphometry and redox homeostasis of adult rats and evaluate the effects of maternal treatment with metformin and pentoxifylline. Female rats were induced to T2D, then treated with metformin and pentoxifylline, or co-treated with both drugs. The females were mated, the male offspring were sacrificed on postnatal day 90, and the testicles were collected for analysis. Metformin protected the tubular compartment, with the maintenance of the Sertoli cell population and daily sperm production. Pentoxifylline attenuated the effects of diabetes on Leydig cells, in addition to stimulating testosterone production and lowering lipid peroxidation. Intrauterine exposure to T2D results in important testicular alterations that compromise gonadal function, and the co-treatment with metformin and pentoxifylline may represent a promising therapy that attenuates these effects by combining the positive influences in both the tubular and interstitial compartments of the testicular parenchyma.

The solute carrier family 7 member 11 (SLC7A11) is regulated by LH/androgen and required for cystine/glutathione homeostasis in mouse Sertoli cells

Luteinizing hormone (LH) stimulates testosterone production from Leydig cells. Both LH and testosterone play important roles in spermatogenesis and male fertility. To identify LH - and testosterone - responsive transporter genes that play key roles in spermatogenesis, we performed large-scale gene expression analyses on testes obtained from adult control and Lhb knockout mice. We found a significant reduction in cystine/glutamate transporter encoding Slc7a11 mRNA in testes of Lhb null mice. We observed that Slc7a11/SLC7A11 expression was initiated pre-pubertally and developmentally regulated in mouse testis. Immunolocalization studies confirmed that SLC7A11 was mostly expressed in Sertoli cells in testes of control and germ cell-deficient mice. Western blot analyses indicated that SLC7A11 was significantly reduced in testes of mutant mice lacking either LH or androgen receptor selectively in Sertoli cells. Genetic and pharmacological rescue of Lhb knockout mice restored the testicular expression of Slc7a11 comparable to that observed in controls. Additionally, Slc7a11 mRNA was significantly suppressed upon Sertoli cell/testicular damage induced in mice by cadmium treatment. Knockdown of Slc7a11 in vitro in TM4 Sertoli cells or treatment of mice with sulfasalazine, a SLC7A11 inhibitor caused a significant reduction in intracellular cysteine and glutathione levels but glutamate content remained unchanged as determined by metabolomic analysis. Knockdown of Slc7a11 resulted in compensatory upregulation of other glutamate transporters belonging to the Slc1a family presumably to maintain intracellular glutamate levels. Collectively, our studies identified that SLC7A11 is an LH/testosterone-regulated transporter that is required for cysteine/glutathione but not glutamate homeostasis in mouse Sertoli cells.

Effects of Nerve Growth Factor-β From Bull Seminal Plasma on Steroidogenesis and Angiogenic Markers of the Bovine Pre-ovulatory Follicle Wall Cell Culture.

Nerve growth factor-β (NGF) is critical for ovulation in the mammalian ovary and is luteotrophic when administered systemically to camelids and cattle. This study aimed to assess the direct effects of purified bovine NGF on steroidogenesis and angiogenic markers in the bovine pre-ovulatory follicle. Holstein heifers (n = 2) were synchronized with a standard protocol, and heifers with a preovulatory follicle (≥ 12 mm) had the ovary containing the dominant follicle removed via colpotomy. Pre-ovulatory follicles were dissected into 24 pieces containing theca and granulosa cells that were randomly allocated into culture media supplemented with either purified bovine NGF (100 ng/mL) or untreated (control) for 72 h. The supernatant media was harvested for quantification of progesterone, testosterone, and estradiol concentrations, whereas explants were subjected to mRNA analyses to assess expression of steroidogenic and angiogenic markers. Treatment of follicle wall pieces with NGF upregulated gene expression of steroidogenic enzyme HDS17B (P = 0.04) and increased testosterone production (P < 0.01). However, NGF treatment did not alter production of progesterone (P = 0.81) or estradiol (P = 0.14). Consistently, gene expression of steroidogenic enzymes responsible for producing these hormones (STAR, CYP11A1, HSD3B, CYP17A1, CYP19A1) were unaffected by NGF treatment (P ≥ 0.31). Treatment with NGF downregulated gene expression of the angiogenic enzyme FGF2 (P = 0.02) but did not alter PGES (P = 0.63), VEGFA (P = 0.44), and ESR1 (P = 0.77). Collectively, these results demonstrate that NGF from seminal plasma may interact directly on the theca and granulosa cells of the bovine pre-ovulatory follicle to stimulate testosterone production, which may be secondary to theca cell proliferation. Additionally, decreased FGF2 expression in NGF-treated follicle wall cells suggests hastened onset of follicle wall cellular remodeling that occurs during early luteal development.

Placental Cryoextract Corrects the Level of Thyroid Hormones in Rats

Effectiveness of cryopreserved placental drug ‘Placental cryoextract’ to correct the reproductive system disorders, occurring against the background of low levels of thyroid hormones, was studied in 50 male rats with mercazolyl hypothyroidism. Using standard test systems for animals, the level of total and free forms of thyroid hormones, total testosterone and estradiol was determined. The morphofunctional state of sperm (number, motility, pathological forms) was traditionally assessed. It was shown that the introduction of the biological product (at a dose of 50–150 μl / kg) restored the functional activity of the thyroid gland of animals, and the lowest dose was more effective. Placental cryoextract also had a dose-dependent effect on the reproductive system of animals with hypothyroidism: the most effective dose was 150 μl / kg, which maximally restored the morphofunctional parameters of sperm and stimulated testosterone production as well as normalized the Ts / E2 ratio. Cryopreserved placenta extract can be considered as a potential drug for the correction of hypothyroidism and reproductive disorders of endocrine origin in male rats.

The Effect of Metformin Therapy on Luteinizing Hormone Receptor Agonist-Mediated Stimulation of Testosterone Production and Spermatogenesis in Diabetic Rats

The Effect of Metformin Therapy on Luteinizing Hormone Receptor Agonist-Mediated Stimulation of Testosterone Production and Spermatogenesis in Diabetic Rats

Genetics of hypogonadotropic hypogonadism.

Male congenital hypogonadotropic hypogonadism (CHH) is a heterogenous group of genetic disorders that cause impairment in the production or action of gonadotropin releasing hormone (GnRH). These defects result in dysfunction of the hypothalamic-pituitary-gonadal hormone axis, leading to low testosterone levels and impaired fertility. Genetic testing techniques have expanded our knowledge of the underlying mechanisms contributing to CHH including over 30 genes to date implicated in the development of CHH. In some cases, non-reproductive signs or symptoms can give clues as to the putative genetic etiology, but many cases remain undiagnosed with less than 50% identified with a specific gene defect. This leads to many patients labelled as “idiopathic hypogonadotropic hypogonadism”. Medical and family history as well as physical exam and laboratory features can aid in the identification of hypogonadotropic hypogonadism (HH) that is associated with specific medical syndromes or associated with other pituitary hormonal deficiencies. Genetic testing strategies are moving away from the classic practice of testing for only a few of the most commonly affected genes and instead utilizing next generation sequencing techniques that allow testing of numerous potential gene targets simultaneously. Treatment of CHH is dependent on the individual’s desire to preserve fertility and commonly include human chorionic gonadotropin (hCG) and recombinant follicle stimulating hormone (rFSH) to stimulate testosterone production and spermatogenesis. In situations where fertility is not desired, testosterone replacement therapies are widely offered in order to maintain virilization and sexual function.

Discovery and Preclinical Development of Orally Active Small Molecules that Exhibit Highly Selective Follicle Stimulating Hormone Receptor Agonism.

An orally active follicle stimulating hormone receptor allosteric agonist would provide a preferred treatment for over 16 million infertile women of reproductive age in low complexity methods (ovulation induction-intrauterine insemination) or in high complexity methods (controlled ovarian stimulation-in vitro fertilization). We present two oral follicle stimulating hormone receptor allosteric agonist compounds that have the desired pharmacology, drug metabolism, pharmacokinetics, and safety profile for clinical use. These molecules provide a single agent suitable for ovulation induction-intrauterine insemination or controlled ovarian stimulation-in vitro fertilization that is more convenient for patients and achieves similar preclinical efficacy as rec-hFSH. TOP5668, TOP5300 were evaluated in vitro in Chinese hamster ovary cells transfected with individual glycoprotein receptors measuring cAMP (FSHR, LH/CGR, thyroid stimulating hormone receptor). TOP5668 was found to have solely follicle stimulating hormone receptor allosteric agonist activity while TOP5300 was found to have mixed follicle stimulating hormone receptor allosteric agonist and LHR-AA activity. Both compounds stimulated concentration-dependent increases in estradiol production from cultured rat granulosa cells in the presence or absence of low dose rec-hFSH, while only TOP5300 stimulated testosterone production from rat primary Leydig cells. In pooled human granulosa cells obtained from patients undergoing controlled ovarian stimulation-in vitro fertilization, TOP5300 stimulated 7-fold greater maximal estradiol response than rec-hFSH and TOP5668 was 10-fold more potent than TOP5300. Both TOP5300 and TOP5668 stimulated follicular development in immature rat to the same efficacy as recombinant follicle stimulating hormone. In mice treated with TOP5300, in the presence of low dose of follicle stimulating hormone, there were no differences in oocyte number, fertilization rate, and hatched blastocyst rate in mice with TOP5300 and low dose follicle stimulating hormone vs. reference proteins pregnant mare serum gonadotropin or high dose rec-hFSH. ADME/PK and safety profiles were favorable. In addition, there was no appreciable activity on thyroid hormones by TOP5300 in 14-days toxicological study in rat or dog. The selected lead compound, TOP5300 stimulated a more robust increase in estradiol production from granulosa-lutein cells from women with polycystic ovarian syndrome patient compared to rec-hFSH. Conclusions: Two novel oral FSHR allosteric agonist, TOP5668 and TOP5300, were found to mimic the biological activity of rec hFSH in preclinical studies. Both compounds led to folliculogenesis and superovulation in rat and mice. Specifically, TOP5300 led to a similar number of ovulated oocytes that fertilized and developed into hatched blastocysts in mice when compared to rec-hFSH. The safety profile demonstrated lack of toxicity.

A Review of foods and food supplements increasing testosterone levels

Androgens are essential for male physical activity. Age-related androgen deficiency, known as late-onset hypogonadism (LOH), is considered a risk factor for several diseases. There are many men's health supplements on the market. Therefore, the purpose of this review is to summarize the food ingredients that have been suggested in published literature to increase testosterone levels. A review of previously reported animal studies suggested that 5 representative nutritional components, 7 food ingredients, and 25 supplements were associated with testosterone. Some food and supplements influence testosterone levels in various animals by directly increasing testosterone or suppressing the decrease in testosterone production due to testicular toxicity. There are three mechanisms by which foods or supplements increase testosterone production: 1) regulating luteinizing hormone, the hormone that stimulates testosterone production, 2) regulating testosterone synthase in the testis, and 3) regulating testosterone-degrading enzymes. In contrast, suppressing the decrease in testosterone depends on the antioxidant effect of the foods. Although detailed mechanistic studies and clinical trials are required to validate these findings, the use of food to regulate testosterone levels is a promising therapeutic option.

ВЛИЯНИЕ НИЗКОМОЛЕКУЛЯРНЫХ АЛЛОСТЕРИЧЕСКИХ АГОНИСТОВ РЕЦЕПТОРА ЛЮТЕИНИЗИРУЮЩЕГО ГОРМОНА НА ЕГО ЭКСПРЕССИЮ В СЕМЕННИКАХ САМЦОВ КРЫС

Human chorionic gonadotropin (hCG) and luteinizing hormone (LH) regulate testicular steroidogenesis by interacting with the orthosteric site located in the extracellular domain of the LH receptor (LHR). The use of hCG and LH in medicine is fraught with side effects caused by hyperactivation of LH-dependent cascades and the development of resistance of target cells to endogenous gonadotropins due to a decrease in the activity and expression of LHR. An alternative to gonadotropins is low-molecular-weight compounds which interact with the LHR transmembrane allosteric site. The aim of this work was to study the relationship between the steroidogenic effects of hCG and thieno[2,3-d]pyrimidine derivatives (TPDs) with an activity of LHR agonists and their ability to influence the expression of the LRH-encoding Lhr gene both in vitro, when acting on the primary culture of rat Leydig cells, and in vivo, when administered to male rats. hCG stimulated testosterone production with a high efficiency at an early stage of its effect on Leydig cells (after 30 min) and upon a single administration to male rats (after 3 h), exceeding TPDs in activity by this parameter. After 1–3 h of acting on Leydig cells and long-term administration to male rats, the steroidogenic effect of hCG decreased and became comparable to that of TPDs. In Leydig cells and rat testes, hCG suppressed Lhr gene expression, which was partially restored in vivo on days 7–10 being accompanied by a slight increase in the steroidogenic effect of hCG, though to a significantly smaller extent than on the first day. The treatment with TP03, which was the most active of the TPDs studied, had a little effect on Lhr gene expression in Leydig cells but significantly increased it in rat testes after long-term administration of the drug. The steroidogenic effect of TP03 positively correlated with Lhr gene expression. When TP03 was applied to aging rats, its steroidogenic effect decreased, most likely, due to the absence of its stimulating effect on LHR expression. Thus, after long-term administration, TPDs exert a moderately expressed, stable over time, stimulating effect on testosterone production but do not decrease LHR expression, which prevents testicular resistance to endogenous gonadotropins under conditions of steroidogenesis stimulation.

Chemerin Impairs In Vitro Testosterone Production, Sperm Motility, and Fertility in Chicken: Possible Involvement of Its Receptor CMKLR1.

The chemokine chemerin is a novel adipokine involved in the regulation of energy metabolism but also female reproductive functions in mammals. Its effects on male fertility are less studied. Here, we investigated the involvement of chemerin in chicken male reproduction. Indeed, the improvement of the sperm of roosters is a challenge for the breeders since the sperm quantity and quality have largely decreased for several years. By using specific chicken antibodies, here we show that chemerin and its main receptor CMKLR1 (chemokine-like receptor 1) are expressed within the chicken testis with the lowest expression in adults as compared to the embryo or postnatal stages. Chemerin and CMKLR1 are present in all testicular cells, including Leydig, Sertoli, and germinal cells. Using in vitro testis explants, we observed that recombinant chicken chemerin through CMKLR1 inhibits hCG (human chorionic gonadotropin) stimulated testosterone production and this was associated to lower 3βHSD (3beta-hydroxysteroid dehydrogenase) and StAR (steroidogenic acute regulatory protein) expression and MAPK ERK2 (Mitogen-Activated Protein Kinase Extracellular signal-regulated kinase 2) phosphorylation. Furthermore, we demonstrate that chemerin in seminal plasma is lower than in blood plasma, but it is negatively correlated with the percentage of motility and the spermatozoa concentration in vivo in roosters. In vitro, we show that recombinant chicken chemerin reduces sperm mass and individual motility in roosters, and this effect is abolished when sperm is pre-incubated with an anti-CMKLR1 antibody. Moreover, we demonstrate that fresh chicken sperm treated with chemerin and used for artificial insemination (AI) in hen presented a lower efficiency in terms of eggs fertility for the four first days after AI. Taken together, seminal chemerin levels are negatively associated with the rooster fertility, and chemerin produced locally by the testis or male tract could negatively affect in vivo sperm quality and testosterone production through CMKLR1.

Pretreatment of Rats with an Allosteric Luteinizing Hormone Receptor Agonist Enhances Chorionic Gonadotropin-Induced Stimulation of Testosterone Production

Pretreatment of Rats with an Allosteric Luteinizing Hormone Receptor Agonist Enhances Chorionic Gonadotropin-Induced Stimulation of Testosterone Production

Divergent Roles of CYP26B1 and Endogenous Retinoic Acid in Mouse Fetal Gonads.

In female mammals, germ cells enter meiosis in the fetal ovaries, while in males, meiosis is prevented until postnatal development. Retinoic acid (RA) is considered the main inducer of meiotic entry, as it stimulates Stra8 which is required for the mitotic/meiotic switch. In fetal testes, the RA-degrading enzyme CYP26B1 prevents meiosis initiation. However, the role of endogenous RA in female meiosis entry has never been demonstrated in vivo. In this study, we demonstrate that some effects of RA in mouse fetal gonads are not recapitulated by the invalidation or up-regulation of CYP26B1. In organ culture of fetal testes, RA stimulates testosterone production and inhibits Sertoli cell proliferation. In the ovaries, short-term inhibition of RA-signaling does not decrease Stra8 expression. We develop a gain-of-function model to express CYP26A1 or CYP26B1. Only CYP26B1 fully prevents STRA8 induction in female germ cells, confirming its role as part of the meiotic prevention machinery. CYP26A1, a very potent RA degrading enzyme, does not impair the formation of STRA8-positive cells, but decreases Stra8 transcription. Collectively, our data reveal that CYP26B1 has other activities apart from metabolizing RA in fetal gonads and suggest a role of endogenous RA in amplifying Stra8, rather than being the initial inducer of Stra8. These findings should reactivate the quest to identify meiotic preventing or inducing substances.

Chronic intermittent hypoxia stimulates testosterone production in rat Leydig cells

AimsThe hypoxia-stimulated response of the endocrine system depends on the kind and duration of hypoxia. Hypoxia has been reported to stimulate testosterone (T) production in rats, but the mechanisms remain to be investigated. Materials and methodsMale rats were divided into two groups. The rats exposed to chronic intermittent hypoxia (CIH) at 8 h/day were housed in a hypoxic chamber (12% O2) for 14 days. Normoxic rats were used as control animals. T was measured after challenging the rat Leydig cells (LCs) with different stimulators, including hCG (0.01 IU/ml), forskolin (10−5 M), 8-bromo-cAMP (10−4 M), A23187 (10−5 M), cyclopiazonic acid (10−4 M), and androstenedione (10−8 M). Meanwhile, the LCs were incubated with trilostane (10−5 M) and/or 25-OH-hydroxycholesterol (10−5 M); thereafter the media were collected for pregnenolone assay. Key findingsIn the CIH group, plasma T levels were increased, but the serum luteinizing hormone (LH) was decreased. Furthermore, at several time intervals after hCG injection, plasma T levels were higher in the CIH group. The evoked-release of T and pregnenolone were significantly increased in the CIH group. Compared with the normoxic group, the CIH group had higher mRNA and protein expression levels of the LH receptor and CYP11A1 but not StAR. The plasma and testicular microvasculature VEGF levels were increased in the CIH group. The testicular vessel distribution was more obvious in CIH rats. SignificanceCIH-induced T secretion might be partially mediated by mechanisms involving the induction of LH receptor expression, testicular angiogenesis, CYP11A1 activity, 17β-HSD activity, and calcium-related pathway.