Follicle-stimulating Hormone Production Research Articles

Effects of follicle-stimulating hormone on energy balance and tissue metabolic health after loss of ovarian function.

Loss of ovarian function imparts increased susceptibility to obesity and metabolic disease. These effects are largely attributed to decreased estradiol (E2), but the role of increased follicle-stimulating hormone (FSH) in modulating energy balance has not been fully investigated. Previous work that blocked FSH binding to its receptor in mice suggested this hormone may play a part in modulating body weight and energy expenditure after ovariectomy (OVX). We used an alternate approach to isolate the individual and combined contributions of FSH and E2 in mediating energy imbalance and changes in tissue-level metabolic health. Female Wistar rats were ovariectomized and given the gonadotropin releasing hormone (GnRH) antagonist degarelix to suppress FSH production. E2 and FSH were then added back individually and in combination for a period of 3 wk. Energy balance, body mass composition, and transcriptomic profiles of individual tissues were obtained. In contrast to previous studies, suppression and replacement of FSH in our paradigm had no effect on body weight, body composition, food intake, or energy expenditure. We did, however, observe organ-specific effects of FSH that produced unique transcriptomic signatures of FSH in retroperitoneal white adipose tissue. These included reductions in biological processes related to lipogenesis and carbohydrate transport. In addition, rats administered FSH had reduced liver triglyceride concentration (P < 0.001), which correlated with FSH-induced changes at the transcriptomic level. Although not appearing to modulate energy balance after loss of ovarian function in rats, FSH may still impart tissue-specific effects in the liver and white adipose tissue that might affect the metabolic health of those organs.NEW & NOTEWORTHY We find no effect of follicle-stimulating hormone (FSH) on energy balance using a novel model in which rats are ovariectomized, subjected to gonadotropin-releasing hormone antagonism, and systematically given back FSH by osmotic pump. However, tissue-specific effects of FSH on adipose tissue and liver were observed in this study. These include unique transcriptomic signatures induced by the hormone and a stark reduction in hepatic triglyceride accumulation.

Effect of a Single Injection of GnRH Analog Alone and at the Time of AI on Reproductive Performance of Nili Ravi Buffaloes

Introduction: The gonadotropin-releasing hormone (GnRH) is a decapeptide hormone released from basal neurons of the hypothalamus. It stimulates the production of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the pituitary. The objective of the study was to evaluate the effect of a single injection of gonadotropin-releasing hormone (GnRH) analog at the time of artificial insemination (AI) on buffalo estrus, conception, pregnancy, and calving rate. Materials and methods: The anestrus nulliparous Nili Ravi buffalo heifers (n=80) were divided into 4 groups randomly. Group A (n=20) received only a single injection of GnRH analog at start of the experiment (Day 0), group B (n=20) received a single injection of GnRH analog at Day 0 and prostaglandine (PGF2α) at Day 7, group C (n=20) received progesterone sponge for 7 days, and group D (n=20) received progesterone sponge for 7 days and PGF2α at Day 9. In 2nd study, buffaloes (n=60) expressing first (n=20), second (n=20), and third (n=20) postpartum estrus were enrolled. Moreover, heifers (n=20), expressing estrus first time were also included. Animals (n=10) from each group, received a single injection of GnRH analog at the time of AI were named as treatment group and the control (n=10) did not receive any treatment. Pregnancy tests were performed with the help of ultrasound on days 35 and 65 post-AI. Results: The pregnancy and calving rates were lower in GnRH group compared to other treatments. Similarly, the administration of GnRH analog did not increase pregnancy rates in treatment groups. Conclusion: The single injection of GnRH analog alone at the time of AI did not improve the reproductive performance of buffaloes.

Aquisição da dependência de gonadotrofinas pelos folículos antrais iniciais e os desafios para promover o seu crescimento in vitro

Abstract This review aims to discuss the main factors involved in the development of early antral follicles until gonadotropin dependence. This follicular phase is characterized by intense proliferation of granulosa cells, formation of a fluid-filled cavity, morphological differentiation of cumulus cells, mural granulosa cells and recruitment of theca cells. The interaction between oocyte, granulosa and theca cells is crucial for follicular growth and hormone production. Growth factors produced by the oocyte, such as growth and differentiation factor-9 (GDF-9) and bone morphogenetic protein-15 (BMP-15), regulate granulosa cell proliferation and differentiation and antral cavity development, as well as stimulate the production of follicle-stimulating hormone (FSH) receptors in granulosa cells. In response to FSH, granulosa cells secrete C-type natriuretic peptide (CNP), which acts through its receptor to increase cyclic guanosine monophosphate (cGMP) production and consequently follicular development. Granulosa cells also produce insulin-like growth factor-1 (IGF-1) and increase aromatase enzyme activity, which results in greater sensitivity to gonadotropins and follicular steroidogenesis. The absence of IGF-1 signaling causes cessation of follicular growth at the early antral stage. Many other local factors are involved in the regulation of follicular development. Therefore, this review brings relevant data for a better understanding of the mechanisms involved in the control of early antral follicle growth, emphasizing the role of endocrine and paracrine factors, the oocyte-granulosa cell interaction and the processes of follicular atresia. The challenges for the establishment of efficient culture systems for in vitro growth of early antral follicles are also discussed.

Effects of intracerebroventricular administration of calcitonin gene-related peptide (CGRP) on sex hormones and sperm quality in rats.

Therapeutic strategies with calcitonin gene-related peptide (CGRP) or its receptor have been investigated, but there are few studies regarding the possible harmful effects of CGRP in other body organs. This study aimed to investigate the effect of intracerebroventricular (ICV) injection of CGRP on sex hormones and sperm quality in rats. Twelve male rats were divided into two groups (n=6 per group). The first group (control) rats were injected with 5µl artificial cerebrospinal fluid intra-ICV; the second group rats, 5µl (1.5nmol) CGRP. The levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone were measured. Epididymal sperms were used to determine the sperm parameters. The levels of testosterone, LH and FSH in CGRP group was significantly lower than in artificial cerebrospinal fluid (ACSF) group (P<0.05). The concentration and motility of sperm in CGRP group was significantly lower than in ACSF group (P<0.05). In CGRP group live spermatozoa and intact acrosome significantly reduced compared to the ACSF group (P<0.05). In addition, in CGRP group dead spermatozoa and lose acrosome significantly increased compared to the ACSF group (P<0.05). ICV injection of CGRP may reduce sperm quality, probably through induction of an imbalance in FSH and LH production as well as testosterone.

COMPARATIVE EFFECTS OF FRESH AND FERMENTED FRUIT JUICE OF Morinda citrifolia (RUBIACEAE) ON REPRODUCTIVE PARAMETERS IN ADULT MALE RATS

Fresh and fermented fruit juices of Morinda citrifolia are used in ethnomedicine to improve male fertility. The comparative effects of the fresh and fermented fruit juice of M. citrifolia on semen parameters and hormonal profile in adult male rats were evaluated in this study. Thirty-five matured male rats (185-220 g) were divided into seven groups of five animals each. Group 1 served as the normal control. Groups 2 - 7 were further subdivided into two sub-groups 2-4 and 5-7. Animals in groups 2 - 4 were treated orally with 2.5, 5 and 10 ml/kg of the fresh juice of M. citrifolia respectively while animals in groups 5- 7 received 2.5, 5 and 10 ml/kg of the fermented fruit juice respectively for 60 days. Normal control animals (group 1) received 10 ml/kg of distilled water. Serum samples obtained from animals were used to assess for levels of testosterone, progesterone, luteinizing and follicle-stimulating hormones. Sperm count, morphology and motility were equally analysed. Histological evaluation of the testis was also carried out. The Fresh juice significantly (p&lt;0.05) increased serum levels of testosterone and follicle-stimulating hormone, while the fermented juice produced a significant increase in serum level of testosterone only. The serum levels of luteinizing hormone and progesterone were unaffected by both juices. The sampled juices produced varied effects on other measured parameters. The ability to enhance the production of testosterone and follicle-stimulating hormone production was exhibited by both juices. However, the fresh juice showed a higher possibility of increasing hormone production.

Activating Transcription Factor 3 Stimulates Follicle-Stimulating Hormone-β Expression In Vitro But Is Dispensable for Follicle-Stimulating Hormone Production in Murine Gonadotropes In Vivo.

Follicle-stimulating hormone (FSH), a dimeric glycoprotein produced by pituitary gonadotrope cells, regulates spermatogenesis in males and ovarian follicle growth in females. Hypothalamic gonadotropin-releasing hormone (GnRH) stimulates FSHβ subunit gene (Fshb) transcription, though the underlying mechanisms are poorly understood. To address this gap in knowledge, we examined changes in pituitary gene expression in GnRH-deficient mice (hpg) treated with a regimen of exogenous GnRH that increases pituitary Fshb but not luteinizing hormone β (Lhb) messenger RNA levels. Activating transcription factor 3 (Atf3) was among the most upregulated genes. Activating transcription factor 3 (ATF3) can heterodimerize with members of the activator protein 1 family to regulate gene transcription. Co-expression of ATF3 with JunB stimulated murine Fshb, but not Lhb, promoter-reporter activity in homologous LβT2b cells. ATF3 also synergized with a constitutively active activin type I receptor to increase endogenous Fshb expression in these cells. Nevertheless, FSH production was intact in gonadotrope-specific Atf3 knockout [conditional knockout (cKO)] mice. Ovarian follicle development, ovulation, and litter sizes were equivalent between cKOs and controls. Testis weights and sperm counts did not differ between genotypes. Following gonadectomy, increases in LH secretion were enhanced in cKO animals. Though FSH levels did not differ between genotypes, post-gonadectomy increases in pituitary Fshb and gonadotropin α subunit expression were more pronounced in cKO than control mice. These data indicate that ATF3 can selectively stimulate Fshb expression in vitro but is not required for FSH production in vivo.

Maximizing Correction of Infertility with Moderate to Marked Diminished Egg Reserve in Natural Cycles by Up-Regulating Follicle Stimulating Hormone Receptors

Many infertility specialists advise women with diminished oocyte reserve (DOR) that their remaining oocytes probably are of poor quality similar to women of advanced reproductive age. There have been studies, especially employing in vitro fertilization-embryo transfer (IVF-ET), showing very poor live delivered pregnancy rates despite the transfer of morphologically normal embryos in women even with mild DOR. However, other data suggests that the low pregnancy rates are related to the use of high dosages of follicle stimulating hormone (FSH) drugs which down-regulate some key FSH dependent enzymes, cytokines, or proteins required for proper embryo implantation. Some studies have shown that techniques that favor FSH receptor up-regulation, rather than down-regulation, can provide the chance of live delivery 80% as well in women ≤ 35 with DOR, 70% for women 36-39, and 50% for women 40-42. Though some infertility specialists will encourage women whose only infertility issue is DOR, who reject the initial suggestion to consider donor oocytes, to proceed immediately with IVF-ET to maximize success, pregnancies are quite possible with natural conception. Thus, it seems imprudent to make couples undergo the financial burden of IVF-ET in the absence of a significant tubal or male factor problem. Not only have live deliveries occurred in women with DOR, using the principle described to achieve a mature dominant follicle followed by proper luteal phase support, with serum FSH levels over 100 mIU/mL, but also serum Anti-Mullerian Hormone (AMH) levels that were undetectable. This even applies to women in overt menopause where FSH up-regulation was achieved by negative feedback to the pituitary using ethinyl estradiol inhibiting FSH release, or down-regulation of hypothalamic-pituitary stimulation of FSH production by using gonadotropin releasing hormone agonists or antagonists.

Linzagolix: First Approval.

Linzagolix (Yselty®) is an orally administered, selective, non-peptide small molecule gonadotrophin releasing hormone (GnRH) receptor antagonist that is being developed by Kissei Pharmaceutical for the treatment of uterine fibroids and endometriosis in women of reproductive age. Linzagolix binds to and blocks the GnRH receptor in the pituitary gland, modulating the hypothalamic pituitary-gonadal axis and dose-dependently reducing serum luteinising hormone and follicle-stimulating hormone production and serum estradiol levels. In June 2022, linzagolix was approved for the treatment of moderate to severe symptoms of uterine fibroids in adult women of reproductive age in the EU. Linzagolix is under regulatory review the USA for this indication and is in phase 3 clinical development in the treatment of pain associated with endometriosis. This article summarizes the milestones in the development of linzagolix leading to this first approval for the treatment of moderate to severe symptoms of uterine fibroids in adult women of reproductive age.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40265-022-01753-9.

Effects of letrozole cotreatment on endocrinology and follicle development in women undergoing ovarian stimulation in an antagonist protocol.

What are the downstream endocrine and paracrine consequences of letrozole (LZ) cotreatment during ovarian stimulation and is follicle growth and recruitment affected? Letrozole cotreatment induces marked changes in both the follicular and luteal phase endocrinology causing potentiation of follicle diameter and an improved corpus luteum function without affecting the secondarily recruited follicle cohort. Letrozole is a third-generation aromatase inhibitor that is well-established as an effective ovulatory agent, while its possible benefits in standard in vitro fertilization protocols are less thoroughly investigated. This study included a double-blinded, placebo-controlled, randomized study with LZ or placebo intervention during ovarian stimulation for IVF treatment, an observational preceding baseline natural cycle and a succeeding follow-up visit. Participants were enrolled between August 2016 and November 2018. Data from the randomized, stimulated cycle were part of a larger RCT, which was previously published. The study was conducted at a public fertility clinic at Herlev Hospital, Denmark, including 31 healthy, normo-responding women eligible for IVF treatment. They underwent a natural baseline cycle and were subsequently randomized to receive either LZ 5 mg (n = 16) or placebo (n = 15) daily during ovarian stimulation from cycle day (CD) 2-3 until induction of ovulation. Throughout both cycles, monitoring was performed every third day with transvaginal ultrasound for assessment of follicle count and diameter, and blood analyses for the determination of twelve endocrine and paracrine parameters. A follow-up assessment was performed at CD2-3 in the succeeding cycle. In the randomized part of the study, we determined differences in blood parameters, follicle recruitment, and follicle diameter. In the observational part of the study, we assessed follicle recruitment in between cycles and its correlation to endocrine parameters. Letrozole cotreatment significantly suppressed oestradiol (E2) concentrations in the follicular phase (area under the curve (AUC) -58% (95% CI [-70%; -43%], P < 0.001)) and luteal phase (AUC -39% [-63%; -1%], P = 0.046). This had a marked effect on the endocrine and paracrine output with increased follicular phase luteinizing hormone (AUC +37% [3%; 82%], P = 0.033), androstenedione (AUC +36% [6%; 74%], P = 0.016), testosterone (AUC +37% [7%; 73%], P = 0.013) and 17-OH-progesterone (AUC +114% [10%; 318%], P = 0.027). Furthermore, follicle-stimulating hormone (FSH) was increased at stimulation day 5 in the LZ group (P < 0.05). In the luteal phase, increased corpus luteum output was reflected by elevated progesterone (AUC +44% [1%; 104%], P = 0.043), inhibin A (AUC +52% [11%; 108%], P = 0.011), androstenedione (AUC +31% [9%; 58%], P = 0.006) and testosterone (AUC +29% [6%; 57%], P = 0.012) in the LZ group. The altered balance between oestrogens and androgens was reflected in a markedly reduced SHBG concentration in the LZ group throughout the luteal phase (AUC -35% [-52%; -11%], P = 0.009). Endocrine and paracrine parameters were similar between groups at the follow-up visit. Letrozole cotreatment significantly increased the mean number of follicles >16 mm at oocyte retrieval (7.2 vs 5.2, difference: 2.0, 95% CI [0.1; 3.8], P = 0.036), while the mean total number of follicles at oocyte retrieval was the same (23.7 vs 23.5, difference: 0.2 [-5.8; 6.1], P = 0.958), and the mean FSH consumption during the stimulated cycle was similar (1500 vs 1520 IU, difference -20 IU [-175; 136], P = 0.794). Between cycles, the mean antral follicle count at CD2-3 was unchanged (natural cycle 19.0, stimulated cycle 20.9, follow-up cycle 19.7, P = 0.692) and there was no effect of LZ cotreatment on the recruitment of the next follicle cohort (test for interaction, P = 0.821). This study included a relatively small, selected group of healthy women with an expected normal ovarian function and reserve, and the effects of LZ may therefore be different in other patient groups. We confirm some previous findings concerning increased follicle growth and increased endogenous FSH and androgen production, which support the rationale for further studies on the use of LZ cotreatment, for example, as a form of endogenous androgen priming sensitizing the follicle to FSH. Letrozole appears to improve the luteal phase with better stimulation of corpus luteum and progesterone secretion. The authors declare no conflicts of interest relating to the present work. NCT02939898.

Resistance training reduced luteinising hormone levels in postmenopausal women in a substudy of a randomised controlled clinical trial: A clue to how resistance training reduced vasomotor symptoms.

BackgroundVasomotor symptoms (VMS) are common around menopause. Menopausal hormone therapy is the most effective treatment for VMS. Physical exercise has been proposed as an alternative treatment since physically active women have previously been found to experience fewer VMS than inactive women. In our randomised controlled trial on resistance training to treat VMS, sympoms were reduced by 50% in the intervention group compared with the control group.ObjectivesTo propose a mechanism to explain how resistance training reduced VMS and to assess if luteinizing hormone (LH) and follicle stimulating hormone (FSH) were affected in accordance with the proposed mechanism.Trial design and methodsA substudy of a randomized controlled trial on 65 postmenopausal women with VMS and low physical activity who were randomised to 15 weeks of resistance training three times per week (n = 33) or to a control group (n = 32). To be regarded compliant to the intervention we predecided a mean of two training sessions per week. The daily number of VMS were registered before and during the 15 weeks. Blood samples were drawn for analysis of LH and FSH at baseline and after 15 weeks.ResultsLH decreased significantly in the compliant intervention group compared with the control group (-4.0±10.6 versus 2.9±9.0, p = 0.028 with Mann-Whitney U test). FSH also decreased in the compliant intervention group compared with the control group, however not enough to reach statistical significance (-3.5±16.3 versus 3.2±18.2, p = 0.063 with Mann-Whitney U test). As previously published the number of hot flushes decreased significantly more in the intervention group than in the control group but there was no association between change in LH or FSH and in number of VMS.ConclusionsWe propose that endogenous opiods such as β-endorphin or dynorphin produced during resistance training decreased VMS by stimulating KNDγ-neurons to release neurokinin B to the hypothalamic thermoregulatory centre. Through effects on KNDγ-neurons, β-endorphin could also inhibit GnRH and thereby decrease the production of LH and FSH. The significanty decreased LH in the compliant intervention group compared with the control group was in accordance with the proposed mechanism.

Transcription factor GATA2 may potentiate follicle-stimulating hormone production in mice via induction of the BMP antagonist gremlin in gonadotrope cells

Mammalian reproduction depends on the gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone, which are secreted by pituitary gonadotrope cells. The zinc-finger transcription factor GATA2 was previously implicated in FSH production in male mice; however, its mechanisms of action and role in females were not determined. To directly address GATA2 function in gonadotropes, we generated and analyzed gonadotrope-specific Gata2 KO mice using the Cre-lox system. We found that while conditional KO (cKO) males exhibited ∼50% reductions in serum FSH levels and pituitary FSHβ subunit (Fshb) expression relative to controls, FSH production was apparently normal in cKO females. In addition, RNA-seq analysis of purified gonadotropes from control and cKO males revealed a profound decrease in expression of gremlin (Grem1), a bone morphogenetic protein (BMP) antagonist. We show Grem1 was expressed in gonadotropes, but not other cell lineages, in the adult male mouse pituitary. Furthermore, Gata2, Grem1, and Fshb mRNA levels were significantly higher in the pituitaries of WT males relative to females but decreased in males treated with estradiol and increased following ovariectomy in control but not cKO females. Finally, we found that recombinant gremlin stimulated Fshb expression in pituitary cultures from WT mice. Collectively, the data suggest that GATA2 promotes Grem1 expression in gonadotropes and that the gremlin protein potentiates FSH production. The mechanisms of gremlin action have not yet been established but may involve attenuation of BMP binding to activin type II receptors in gonadotropes, facilitating induction of Fshb transcription by activins or related ligands.

An extremely rare case of pituitary functioning gonadotroph microadenoma accompanied by ovarian hyperstimulation syndrome in a woman of reproductive age

ObjectiveTo report a case of pituitary functioning gonadotroph microadenoma accompanied by ovarian hyperstimulation syndrome (OHSS) in a woman of reproductive age.DesignA case report.SettingTertiary care unit of a university hospital.PatientsA 42-year-old parous woman with bilateral ovarian enlargement presumed to be secondary to a functioning gonadotroph pituitary microadenoma.InterventionsOral contraceptives and endoscopic transsphenoidal surgery for adenoma that initially could not be visualized on a magnetic resonance imaging (MRI) scan.Main Outcome MeasuresMedical and radiographic assessment of endogenously induced OHSS and its resolution after treatment.ResultsThe patient was diagnosed with OHSS secondary to elevations in endogenous levels of follicle-stimulating hormone (FSH). The cranial contrast-enhanced MRI scan did not show any apparent tumor in the pituitary gland. She was, therefore, treated with oral contraceptives, which resulted in a modest resolution of ovarian enlargement; however, this treatment became ineffective 3 years later. A small pituitary adenoma (maximum diameter of 8 mm) was suspected on repeated MRI (2 years after the first MRI). Selective adenomectomy was performed, which resulted in normalization of the ovarian size and resumption of regular menstrual cycles.ConclusionsWe report a case of a functional pituitary microadenoma secreting FSH in quantities significant enough to result in OHSS. The excessive FSH production was resistant to medical therapy; however, surgical treatment was ultimately successful.

Human INHBB Gene Variant (c.1079T&amp;gt;C:p.Met360Thr) Alters Testis Germ Cell Content, but Does Not Impact Fertility in Mice

Testicular-derived inhibin B (α/β B dimers) acts in an endocrine manner to suppress pituitary production of follicle-stimulating hormone (FSH), by blocking the actions of activins (β A/B/β A/B dimers). Previously, we identified a homozygous genetic variant (c.1079T>C:p.Met360Thr) arising from uniparental disomy of chromosome 2 in the INHBB gene (β B-subunit of inhibin B and activin B) in a man suffering from infertility (azoospermia). In this study, we aimed to test the causality of the p.Met360Thr variant in INHBB and testis function. Here, we used CRISPR/Cas9 technology to generate InhbbM364T/M364T mice, where mouse INHBB p.Met364 corresponds with human p.Met360. Surprisingly, we found that the testes of male InhbbM364T/M364T mutant mice were significantly larger compared with those of aged-matched wildtype littermates at 12 and 24 weeks of age. This was attributed to a significant increase in Sertoli cell and round spermatid number and, consequently, seminiferous tubule area in InhbbM364T/M364T males compared to wildtype males. Despite this testis phenotype, male InhbbM364T/M364T mutant mice retained normal fertility. Serum hormone analyses, however, indicated that the InhbbM364T variant resulted in reduced circulating levels of activin B but did not affect FSH production. We also examined the effect of this p.Met360Thr and an additional INHBB variant (c.314C>T: p.Thr105Met) found in another infertile man on inhibin B and activin B in vitro biosynthesis. We found that both INHBB variants resulted in a significant disruption to activin B in vitro biosynthesis. Together, this analysis supports that INHBB variants that limit activin B production have consequences for testis composition in males.

Effects of transforming growth factor β1 on steroidogenesis of feline granulosa cells cultured

Little is known about the hormonal regulation of feline ovarian granulosa cell proliferation and steroidogenesis. To determine if transforming growth factor β1 (TGFB1), activin, epidermal growth factor (EGF), follicle stimulating hormone (FSH), luteinizing hormone (LH), melatonin, and insulin-like growth factor 1 (IGF1) regulate granulosa cell steroidogenesis and proliferation in cats, three experiments were conducted in winter season. Granulosa cells were isolated and treated in vitro with various hormones in serum-free medium for 48h after an initial 48h plating in 10% fetal calf serum. Treatment with IGF1 and FSH increased (P <0.05) estradiol production by 2.3- and 1.33-fold, respectively. In contrast, TGFB1 blocked (P <0.05) IGF1-induced estradiol production and inhibited FSH-induced estradiol production by 60%. Combined with FSH or FSH plus IGF1, TGFB1 inhibited (P <0.05) cell proliferation, whereas TGFB1 increased progesterone production by 2.8-fold in the presence of FSH plus IGF1. EGF decreased (P <0.05) FSH plus IGF1-induced estradiol production by 89% but did not affect progesterone production or cell numbers. Activin did not affect (P >0.10) cell numbers or steroidogenesis in the presence of FSH plus IGF1. Melatonin and LH decreased (P <0.05) estradiol production 53% and 59%, respectively, without affecting progesterone production or cell proliferation. The present study has identified TGFB1 as a major regulator of feline ovarian function, in addition to EGF, IGF1, melatonin, LH and FSH. These studies will provide useful information for future development of fertility control in feline species.

Melatonin Protects the Histologic Structure of the Uterus in Conditions of Zearalenone Intake.

Background:Zearalenone is a widely spread mycotoxin, contaminant of most cereal grains. It has uterotropic, estrogenic and anabolic activity in farm animals. The results are hormonal disbalances as hyperestrogenism, Zearalenone inhibits follicle-stimulating hormone production, thus supressing ovarian follicle development and ovulation. Also, it induces oxidative stress. Melatonin acts as a potent natural antioxidant and regulates the reproductive function by modification of steroidogenesis.Objective:The present study was conducted to provide detailed qualitative histological analysis of uterus of female rats treated with zearalenone and melatonin and contribute to better understanding of the topic.Methods:Forty adult, female Wistar rats were equally divided into five groups: Z group – zearalenone, 0,3 mg/kg, i.g.; M group – melatonin, 10 mg/kg, i.p.; ZM group –concomitant application of zearalenone and melatonin in the same dosing regimen, VZ group–zearalenone vehiculum/sunflower oil, i.g. and MZ group–melatonin vehiculum/5% ethanol in Ringer, i.p. Animals were treated daily for 28 consecutive days. After that period, all animals were sacrificed to obtain samples for qualitative histological analysis using the light microscope.Results:Zearalenone led to the alterations of the uterine structures, predominantly in the endometrium that were characterized by metaplasia and hypertrophy of the epithelial cells and hypercellularity of the stroma. In the myometrium, zearalenone induced hypertrophy and hyperplasia of the myocytes.Conclusion:Melatonin, when applied together with zearalenone, blocked the adverse effects of the zearalenone.

Addition of a carboxy-terminal tail to the normally tailless gonadotropin-releasing hormone receptor impairs fertility in female mice.

Gonadotropin-releasing hormone (GnRH) is the primary neuropeptide controlling reproduction in vertebrates. GnRH stimulates follicle-stimulating hormone (FSH) and luteinizing hormone (LH) synthesis via a G-protein-coupled receptor, GnRHR, in the pituitary gland. In mammals, GnRHR lacks a C-terminal cytosolic tail (Ctail) and does not exhibit homologous desensitization. This might be an evolutionary adaptation that enables LH surge generation and ovulation. To test this idea, we fused the chicken GnRHR Ctail to the endogenous murine GnRHR in a transgenic model. The LH surge was blunted, but not blocked in these mice. In contrast, they showed reductions in FSH production, ovarian follicle development, and fertility. Addition of the Ctail altered the nature of agonist-induced calcium signaling required for normal FSH production. The loss of the GnRHR Ctail during mammalian evolution is unlikely to have conferred a selective advantage by enabling the LH surge. The adaptive significance of this specialization remains to be determined.

The native form of follicle-stimulating hormone is essential for the growth of mouse preantral follicles in vitro

To assess whether the follicle-stimulating hormone (FSH) subunits observed in patients with gonadotroph adenomas (GA) can cause infertility, the effects of subunits and heterodimeric FSH on the in vitro follicle development were evaluated in mice. The partial forms of FSH in follicle culture did not induce development into pseudoantral follicles, whereas follicles cultured with native FSH developed into pseudoantral follicles and produced mature metaphase II oocyte. Therefore, intact FSH is needed for folliculogenesis, implying that production of FSH with a partial structure in GA may result in infertility.

Follicle-Stimulating Hormone Does Not Impact RANKL-Induced Osteoclastogenesis

Postmenopausal osteoporosis has been attributed to decreased estradiol levels. In the hypothalamic-pituitary-gonadal axis, estradiol synthesis is stimulated by follicle-stimulating hormone (FSH). FSH is secreted from the anterior pituitary gland and estradiol feeds back to the hypothalamus and pituitary to suppress FSH production. In postmenopausal women, the loss of estradiol (and inhibin) negative feedback leads to elevated serum FSH levels. It was recently proposed that this increase in FSH also contributes to postmenopausal osteoporosis by stimulating differentiation and activation of bone-resorbing osteoclast cells. Our objectives were to determine whether FSH has direct actions on osteoclast differentiation in vitro and, if so, its mechanism(s) of action. First, a murine leukemic monocyte/macrophage cell line, RAW264.7, was differentiated into osteoclasts by treatment with receptor activator of nuclear factor kappa-B ligand (RANKL, 50 ng/mL) for seven days. As expected, we observed the appearance of osteoclasts, characterized as tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. RANKL also induced expression of established osteoclast differentiation markers, including Trap, cathepsin K (Ctsk), and matrix metalloproteinase-9 (Mmp9). The mRNA expression of FSH receptor (Fshr), however, was low to undetectable both before and after osteoclast differentiation. Co-treatment of RAW264.7 cells with FSH (35, 70 and 140 IU/L) and RANKL did not further impact the expression of Rank, Trap, Ctsk, Mmp-9, or Fshr. Second, primary murine monocytes were differentiated into osteoclasts by treatment with RANKL (50 ng/mL) and macrophage colony-stimulating factor (M-CSF, 25 ng/mL) for five days. FSH co-treatment (70 and 140 IU/L) had no impact on the expression of osteoclast markers, and Fshr expression was low to undetectable both before and after osteoclast differentiation, consistent with the results from RAW264.7 cells. In conclusion, in our hands, FSH does not impact RANKL-induced osteoclast differentiation in immortalized or primary murine monocytes.

Reduced FSH and LH action: implications for medically assisted reproduction.

ABSTRACTLuteinizing hormone (LH) and follicle-stimulating hormone (FSH) play complementary roles in follicle development and ovulation via a complex interaction in the hypothalamus, anterior pituitary gland, reproductive organs, and oocytes. Impairment of the production or action of gonadotropins causes relative or absolute LH and FSH deficiency that compromises gametogenesis and gonadal steroid production, thereby reducing fertility. In women, LH and FSH deficiency is a spectrum of conditions with different functional or organic causes that are characterized by low or normal gonadotropin levels and low oestradiol levels. While the causes and effects of reduced LH and FSH production are very well known, the notion of reduced action has received less attention by researchers. Recent evidence shows that molecular characteristics, signalling as well as ageing, and some polymorphisms negatively affect gonadotropin action. These findings have important clinical implications, in particular for medically assisted reproduction in which diminished action determined by the afore-mentioned factors, combined with reduced endogenous gonadotropin production caused by GnRH analogue protocols, may lead to resistance to gonadotropins and, thus, to an unexpected hypo-response to ovarian stimulation. Indeed, the importance of LH and FSH action has been highlighted by the International Committee for Monitoring Assisted Reproduction Technologies (ICMART) in their definition of hypogonadotropic hypogonadism as gonadal failure associated with reduced gametogenesis and gonadal steroid production due to reduced gonadotropin production or action. The aim of this review is to provide an overview of determinants of reduced FSH and LH action that are associated with a reduced response to ovarian stimulation.

Population PK-PD-PD Modeling of Recombinant Follicle Stimulating Hormone in In Vitro Fertilization/Intracytoplasmic Sperm Injection: Implications on Dosing and Timing of Gonadotrophin Therapy.

This study aimed to characterize an interactive and clinically applicable population pharmacokinetic-pharmacodynamic-pharmacodynamic (PK-PD-PD) model describing follicle-stimulating hormone (FSH)-inhibin B-oocyte relationship in women undergoing assisted reproduction with in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). The study was a prospective analysis of 25 healthy women undergoing IVF/ICSI using gonadotropin-releasing hormone (GnRH) antagonist protocol. The developed model used the FSH PK profiles to predict both inhibin B (first PD end point) and oocyte retrieval (second PD end point). The modeling framework involved 2 stages. First, the FSH-inhibin B model was developed by the simultaneous approach and applied to estimate the individual area under the inhibin B-time curve (AUCInhb ) at the end of stimulation cycles that varied in length in each woman. In the second stage, the estimated AUCInhb was introduced as a link covariate to predict oocyte retrieval and response category. The population FSH-inhibin B model was described as 3 submodels; PK (exogenous), endogenous, and inhibin B PD models. Weight was the main determinant of both endogenous and exogenous FSH exposures. GnRH antagonist therapy was a significant time-varying covariate when tested against the endogenous FSH production rate (P < .001). AUCInhb could be predicted with women's age and weight. Log-transformed AUCInhb was a significant covariate when tested against oocyte retrieval (P < .001). Simulations concluded a target AUCInhb of 144-303 ng·h/mL for optimal ovarian response. The GnRH antagonist was better started on day 7 of the cycle. Covariate-based dosing suggests lower recombinant follicle-stimulating hormone requirements in a thin and/or young population. An interactive web application "GonadGuide" was developed to facilitate the application in clinical practice.