Efficacy and safety of newly developed ganirelix acetate in infertile women for assisted reproductive technology: a prospective, randomised, controlled study.

This study aimed to investigate the efficacy of Ganilever pre-filled syringe (PFS), a newly developed ganirelix acetate, for the inhibition of premature luteinising hormone (LH) surge in in vitro fertilisation (IVF). A prospective randomised controlled study was conducted (NCT03051087). A total of 236 women (Ganilever group: 114, Orgalutran group: 122) were finally analysed. The patients with LH of >10 mIU/mL on the day of human chorionic gonadotropin (hCG) injection were 0 (0.0%) and 3 (2.5%) in the Ganilever and Orgalutran groups, respectively (p= .25). The number of retrieved oocytes from two groups did not show any significant difference (12.0 ± 6.4 vs. 11.8 ± 6.3, p= .73). Furthermore, the two groups did not show significant differences in the number of good-quality oocytes and embryo, and the rate of fertilisation. Similar safety profiles were also observed. In conclusion, Ganilever PFS showed comparable IVF outcomes and safety profile in IVF, as compared to the Orgalutran. Impact StatementWhat is already known on this subject? Premature LH surge during controlled ovarian stimulation results in the induction of luteinisation of the immature follicles. Thus, gonadotrophin-releasing hormone (GnRH) antagonist protocol was suggested as an option for suppression of premature LH surge. Currently, one of GnRH antagonists being widely used is ganirelix acetate (Orgalutran®; Organon, Oss, The Netherlands). Ganilever pre-filled syringe (PFS) is a newly developed GnRH antagonist containing ganirelix acetate as an active ingredient.What do the results of this study add? Our study demonstrated that Ganilever PFS showed comparable IVF outcomes and patient safety profile in infertile women undergoing in IVF-ET, as compared to the Orgalutran.What are the implications of these findings for clinical practice and/or further research? The results of our study will provide another available GnRH antagonist to be used in patients with IVF.

Transient central precocious puberty: a new entity among the spectrum of precocious puberty?

OBJECTIVE: Recently, we observed some cases of Precocious Puberty (PP) with a partial central activation of hypothalamic-pituitary-gonadal (HPG) axis that tended to normalized in 6-12 months. To evaluate the frequency of this form within the spectrum of forms of PP, we retrospectively assessed the clinical, hormonal and ultrasound characteristics of patients attending to our Center for signs of PP, between 2007 and 2017. To hypothesize some causes of this "pubertal poussée" a questionnaire about environmental data was provided to patients. METHODS: 96 girls were recruited for the study and divided into three Groups. Group 1: 56 subjects with Central PP (CPP) requiring treatment with GnRH analogue; Group 2: 22 subjects with transient activation of pubertal axis, that tended to normalize, "Transient CPP"(T-CPP); Group 3: 18 subjects with Isolated Thelarche (IT). RESULTS: Mean age at diagnosis was 6.8 ± 1.0 years in Group 1, 5.9 ± 1.3 years in Group 2 and 5.6 ± 1.5 years in Group 3. A significant increase of diagnosis of T-CPP was observed over the study period. Significantly higher use of some homeopathic medicines and potential exposure to pesticides was reported in Group 2 vs Group 1. CONCLUSIONS: To our knowledge, we first reported a form defined as T-CPP, characterized by partial activation in the HPG axis normalizing over time. An increased use of homeopathic medicines and exposure to environmental pollutants in these patients was evidenced.

GnRH-a-Induced Perimenopausal Rat Modeling and Black Cohosh Preparations' Effect on Rat's Reproductive Endocrine.

Background: Endometriosis (EMS) is an estrogen-dependent disease, which easily recurs after operation. Gonadotropin-releasing hormone agonist (GnRH-a), an estrogen-inhibiting drug, can effectively inhibit the secretion of gonadotropin by pituitary gland, so as to significantly decrease the ovarian hormone level and facilitate the atrophy of ectopic endometrium, playing a positive role in preventing postoperative recurrence. The application of GnRH-a can lead to the secondary low estrogen symptoms, namely the perimenopausal symptoms, and is a main reason for patients to give up further treatment. The add-back therapy based on sex hormones can well address the perimenopausal symptoms, but long-term use of hormones may cause the recurrence of EMS, as well as liver function damage, venous embolism, breast cancer and other risks, which has long been a heated topic in the industry. Therefore, it is necessary to find effective and safe anti-additive drugs soon. Studies at home and abroad show that, as a plant extract, isopropanolic extract of cimicifuga racemosa (ICR) can well relieve the perimenopausal symptoms caused by natural menopause. Some studies have preliminarily confirmed that black cohosh preparations can antagonize perimenopausal symptoms of EMS patients treated with GnRH-a after operation. Objective: To establish a rat model of perimenopausal symptoms induced by GnRH-a injection, for the purposes of laying a foundation for further research and preliminarily exploring the effect of black cohosh preparations on reproductive endocrine of the rat model. Method: The rat model of perimenopausal symptoms was established by GnRH-a injection, and normal saline (NS injection) was used as the control. The rats were randomly divided into four groups according to different modeling methods and drug intervention schemes. GnRH-a injection + normal saline intervention group (GnRH-a + NS), normal saline injection control + normal saline intervention group (NS + NS), GnRH-a injection + estradiol intervention group (GnRH-a + E2), and GnRH-a injection + black cohosh preparations intervention group (GnRH-a + ICR). After modelling was assessed to be successful with the vaginal smear method, the corresponding drugs were given for intervention for 28d. In the process of rat modeling and drug intervention, the skin temperature and anus temperature of the rat tails were measured every other day, the body weights of the rats were measured every other day, and the dosage was adjusted according to the body weight. After the intervention was over, the serum sex hormone level, the uterine weight, the uterine index, and the endometrial histomorphology changes, as well as the ovarian weight, the ovarian index, and the morphological changes of ovarian tissues of each group were measured. Results: (1) The vaginal cell smears of the control group (NS + NS) showed estrous cycle changes, while other model rats had no estrous cycle of vaginal cells. (2) The body weight gains of the GnRH-a + NS, GnRH-a + E2 and GnRH-a + ICR groups were significantly higher than that of the NS + NS control group. The intervention with E2 and ICR could delay the weight gain trend of rats induced by GnRH-A. (3) After GnRH-a injection, the temperature of the tail and anus of rats showed an overall upward trend, and the intervention with E2 and ICR could effectively improve such temperature change. (4) The E2, FSH, and LH levels in the GnRH-a + NS, GnRH-a + E2, and GnRH-a + ICR groups were significantly lower than those in the NS + NS group (P < 0.01). The E2 level was significantly higher and the LH level was significantly lower in the GnRH-a + E2 group than those in the GnRH-a + NS and GnRH-a + ICR groups (P < 0.05). Compared with those of the GnRH-a + NS and GnRH-a + ICR groups, the FSH level of the GnRH-a + E2 group showed a slight downward trend, but the difference was not statistically significant (P > 0.05). There was no significant difference in the levels of sex hormones between the GnRH-a + NS group and GnRH-a + ICR group (P > 0.05). (5) Compared with those of the NS + NS group, the uterine weight and uterine index of the GnRH-a + NS, GnRH-a + E2 and GnRH-a + ICR groups significantly decreased (P < 0.01). In a comparison between the groups, the uterine weight and uterine index in the GnRH-a + NS and GnRH-a + ICR groups were significantly lower than those in the GnRH-a + E2 group (P < 0.01). There was a statistical difference in the uterine weight and uterine index between the GnRH-a + NS group and GnRH-a + ICR group (P > 0.05). (6) Compared with those of the NS + NS group, the ovarian weight and ovarian index of the GnRH-a + NS, GnRH-a + E2 and GnRH-a + ICR groups significantly decreased (P < 0.01). There was no statistical difference in the ovarian weight and ovarian index among the GnRH-a + E2, GnRH-a + NS and GnRH-a + ICR groups (P > 0.05). (7) Compared with those in the NS + NS group, the number of primordial follicles increased significantly, while the number of growing follicles and mature follicles decreased significantly in the GnRH-a + NS, GnRH-a + E2, and GnRH-a + ICR groups (P < 0.01), but there was a statistical difference in the total number of follicles among the four groups (P > 0.05). Conclusions: The GnRH-a injection could achieve the desired effect. The animal model successfully achieved a significant decrease in the E2, FSH, and LH levels in rats, and could cause the rats to have rising body surface temperature similar to hot flashes in the perimenopausal period. The intervention with E2 and ICR could effectively relieve such "perimenopausal symptoms", and ICR had no obvious effect on the serum sex hormone level in rats.

Gonadotropin-releasing hormone-independent effects of recombinant vertebrate ancient long opsin in the goldfish Carassius auratus reveal alternative reproduction pathways.

Vertebrate ancient long (VAL)-opsin is a green-sensitive photoreceptor that shows high sequence similarity to vertebrate ancient opsin, which is considered to play a role in sexual maturation via gonadotropin-releasing hormone (GnRH); however, the role of VAL-opsin in vertebrate sexual maturity remains unclear. Therefore, we investigated the possible role of VAL-opsin in reproduction in the goldfish Carassius auratus under a state of GnRH inhibition. Goldfish were injected with recombinant VAL-opsin protein (0.5 µg/g body mass) and/or the GnRH antagonist cetrorelix (0.5 µg/fish), and changes in the mRNA expression levels of genes associated with goldfish reproduction were measured by quantitative polymerase chain reaction, including those involved in the hypothalamus-pituitary-gonad (HPG) axis, VAL-opsin, GnRH, the gonadotropins (GTHs) luteinizing hormone and follicle-stimulating hormone, and estrogen receptor (ER). Moreover, the fish were irradiated with a green light-emitting diode (520 nm) to observe the synergistic effect on the HPG axis with VAL-opsin. Green LED exposure significantly and slightly increased the VAL-opsin and GnRH levels, respectively; however, these effects were blocked in groups injected with cetrorelix at all time points. Cetrorelix significantly decreased the mRNA levels of GTHs and ER, whereas these hormones recovered by co-treatment with VAL-opsin. These results indicate that green LED is an effective light source to promote the expression of sex hormones in fish. Moreover, VAL-opsin not only affects activity of the HPG axis but also appears to act on the pituitary gland directly to stimulate a new sexual maturation pathway that promotes the secretion of GTHs independent of GnRH.

Rationalising drug delivery using nanoparticles: a combined simulation and immunology study of GnRH adsorbed to silica nanoparticles.

Silica nanoparticles (SiNPs) have been shown to have significant potential for drug delivery and as adjuvants for vaccines. We have simulated the adsorption of GnRH-I (gonadotrophin releasing hormone I) and a cysteine-tagged modification (cys-GnRH-I) to model silica surfaces, as well as its conjugation to the widely-used carrier protein bovine serum albumin (BSA). Our subsequent immunological studies revealed no significant antibody production was caused by the peptide-SiNP systems, indicating that the treatment was not effective. However, the testosterone response with the native peptide-SiNPs indicated a drug effect not found with cys-GnRH-I-SiNPs; this behaviour is explained by the specific orientation of the peptides at the silica surface found in the simulations. With the BSA systems, we found significant testosterone reduction, particularly for the BSA-native conjugates, and an antibody response that was notably higher with the SiNPs acting as an adjuvant; this behaviour again correlates well with the epitope presentation predicted by the simulations. The range of immunological and hormone response can therefore be interpreted and understood by the simulation results and the presentation of the peptides to solution, paving the way for the future rational design of drug delivery and vaccine systems guided by biomolecular simulation.

Evaluation of ovarian and metabolic effects of GnRH modulators in two rat models of polycystic ovary syndrome.

Gonadotropin-releasing hormone (GnRH) modulators are widely used in numerous reproductive conditions including infertility. Several clinical studies showed mixed results regarding the efficacy of GnRH modulators in patients with polycystic ovary syndrome (PCOS). Along with this, few preclinical studies focus on the effect of GnRH modulators in PCOS-induced animals. Therefore, the present study was designed to study the effect of leuprolide and cetrorelix on hormonal, metabolic, and menstrual dysfunction PCOS rats. Prepubertal female rats were divided into four groups: Group I received a normal pellet diet and Groups II, III, and IV received 40% high-fat diet for 105 days. Similarly, adult female rats were divided into four groups: Group I received 1% carboxymethylcellulose (CMC) and Groups II, III, and IV received letrozole (1 mg/kg, per oral [p.o.] in 1% CMC) for 21 days. Thereafter, leuprolide (2.5 µg/rat, s.c.) and cetrorelix (10 µg/kg, subcutaneous [s.c.]) treatment were given to Group III and Group IV animals, respectively, for 21 days. Oral glucose tolerance test, lipid profile, fasting glucose, insulin, estrus cycle, hormonal profile, ovary weight, ovarian histopathological changes, and LHR and FSHR expressions were measured. Treatment with leuprolide and cetrorelix did not improve glucose intolerance, insulin level, insulin sensitivity indices, sex hormone levels, lipid profile, and estrus cycle. Only testosterone level, total cholesterol level, and follicular development were improved. Therefore, it was concluded that both leuprolide and cetrorelix showed improvement in follicular development, which could be helpful for improving fertility in PCOS.

Bone health during endocrine therapy for cancer.

Preservation of bone health remains a long-term clinical challenge in patients with breast and prostate cancer. Osteoporosis, defined by a loss of bone mass and microarchitecture, often results in fragility fractures that are typically associated with a high socioeconomic burden. Endocrine therapy, a mainstay treatment in the management of patients with hormone-sensitive breast and prostate cancer in the adjuvant setting, commonly exerts adverse effects on the musculoskeletal system and is associated with an increased risk of osteoporosis and fractures. Adjuvant use of gonadotropin-releasing hormone analogues, which can also be used in metastatic disease, in combination with tamoxifen in premenopausal women, and aromatase inhibitors in postmenopausal women with hormone-sensitive breast cancer, causes rapid bone loss and fragility fractures. By contrast, selective oestrogen receptor modulators, such as tamoxifen, have bone-protective effects in postmenopausal women. In men with castration-sensitive prostate cancer, androgen deprivation is achieved with drugs that lower gonadotropin levels, and these drugs can be combined with androgen receptor antagonists. These therapies induce a high bone turnover with rapid bone loss that is reminiscent of the changes occurring in early menopause and result in an increased risk of fracture. In this Review, we describe how adjuvant endocrine therapies of breast and prostate cancer impair bone health and outline evidence from randomised controlled trials of strategies to reduce risk of fracture.

Bu-shen-zhu-yun decoction promotes synthesis and secretion of FSHß and LHß in anterior pituitary cells in vitro.

Luteal phase defects (LPD) are an important etiology of infertility which has increased in recent years. Studies have shown that bu-shen-zhu-yun decoction (BSZY-D) can lower the expression of estrogen receptor and progesterone receptor, in rats endometrium of embryonic implantation period, which upregulated by mifepristone, and improve uterine receptivity. The aim of present study was to determine the effect of BSZY-D on the synthesis and secretion of gonadotropic hormones in the anterior pituitary cells of rats. Rats were treated with saline (control) or BSZY-D two times/day for three estrous cycles by gavage. The cerebrospinal fluid (CSF) were collected for further cell treatment. The components in BSZY-D, serum and CSF were analysed by High Performance Liquid Chromatography (HPLC). Cells were either pretreated with normal CSF or BSZY-D/CSF before being stimulated with or without cetrorelix. The mRNA and proteins levels of receptors, hormones, and transcription factors were detected by RT-PCR, western blot analysis and immunostaining. We show that non-toxic concentrations of cetrorelix, a GnRH antagonist, can reduce the mRNA and protein levels of GnRHR, LH, and FSH. This effect could be reversed by the addition of BSZY-D/CSF. We also show decreased mRNA and protein expression of transcription factors, such as CREB, and Egr-1 and secretory vescicles, including SNAP-25 and Munc-18 upon treatment with cetrorelix could be reversed post co-treatment with BSZY-D/CSF. These results indicate that BSZY-D/CSF treatment led to increased levels of GnRHR, transcription factors, and secretory vesicles leading to increased secretion of FSH and LH. Thus, BSZY-D presents a promising candidate to treat luteal phase defects and infertility.

Melatonin inhibits hypothalamic gonadotropin-releasing hormone release and reduces biliary hyperplasia and fibrosis in cholestatic rats.

Melatonin is a hormone produced by the pineal gland with increased circulating levels shown to inhibit biliary hyperplasia and fibrosis during cholestatic liver injury. Melatonin also has the capability to suppress the release of hypothalamic gonadotropin-releasing hormone (GnRH), a hormone that promotes cholangiocyte proliferation when serum levels are elevated. However, the interplay and contribution of neural melatonin and GnRH to cholangiocyte proliferation and fibrosis in bile duct-ligated (BDL) rats have not been investigated. To test this, cranial levels of melatonin were increased by implanting osmotic minipumps that performed an intracerebroventricular (ICV) infusion of melatonin or saline for 7 days starting at the time of BDL. Hypothalamic GnRH mRNA and cholangiocyte secretion of GnRH and melatonin were assessed. Cholangiocyte proliferation and fibrosis were measured. Primary human hepatic stellate cells (HSCs) were treated with cholangiocyte supernatants, GnRH, or the GnRH receptor antagonist cetrorelix acetate, and cell proliferation and fibrosis gene expression were assessed. Melatonin infusion reduced hypothalamic GnRH mRNA expression and led to decreased GnRH and increased melatonin secretion from cholangiocytes. Infusion of melatonin was found to reduce hepatic injury, cholangiocyte proliferation, and fibrosis during BDL-induced liver injury. HSCs supplemented with BDL cholangiocyte supernatant had increased proliferation, and this increase was reversed when HSCs were supplemented with supernatants from melatonin-infused rats. GnRH stimulated fibrosis gene expression in HSCs, and this was reversed by cetrorelix acetate cotreatment. Increasing bioavailability of melatonin in the brain may improve outcomes during cholestatic liver disease.NEW & NOTEWORTHY We have previously demonstrated that GnRH is expressed in cholangiocytes and promotes their proliferation during cholestasis. In addition, dark therapy, which increases melatonin, reduced cholangiocyte proliferation and fibrosis during cholestasis. This study expands these findings by investigating neural GnRH regulation by melatonin during BDL-induced cholestasis by infusing melatonin into the brain. Melatonin infusion reduced cholangiocyte proliferation and fibrosis, and these effects are due to GNRH receptor 1-dependent paracrine signaling between cholangiocytes and hepatic stellate cells.

18F-FDG PET/CT in the Staging and Management of Breast Cancer: Value in Disease Outcome and Planning Therapy.

In hormone receptor-positive locally advanced breast cancer, endocrine therapy becomes an integral part of the therapeutic strategy. There are now significant numbers of available hormonal directed compounds, including selective aromatase and mTOR inhibitors, which allow an important therapeutic advance in these patients. Sequential F-FDG PET/CT studies provided essential information regarding response to different treatments, including targeted therapies, and adverse therapeutic effects that helped to better define the right moment to implement each therapeutic approach.

Effects of pomegranate extract in supplementing gonadotropin-releasing hormone therapy on idiopathic central precocious puberty in Chinese girls: a randomized, placebo-controlled, double-blind clinical trial.

Central precocious puberty (CPP) without organic abnormality is called idiopathic CPP (ICPP). The objective of this trial was to evaluate the effects of pomegranate extract in supplementing gonadotropin-releasing hormone (GnRH) analog therapy on ICPP-affected girls in the Chinese population. 286 girls, diagnosed with ICPP were initially enrolled into this trial, and among them 225 eligible patients were randomized to receive a combinational GnRH analog treatment supplemented with either a placebo or pomegranate extract on a daily basis for a period of 3 months. Their demographics, secondary sexual characteristics and hormone profiles were analyzed at baseline and end of trial. After 3 months of treatment, demographic profiles including bone age, growth velocity and height standard deviation score for bone age, and secondary sexual characteristics including uterus and ovary volume, as well as serum hormone profiles including estradiol, peak luteinizing hormone and insulin-like growth factor 1 were all significantly improved in girls receiving a combinational treatment of both GnRH analog and pomegranate extract. Daily consumption of pomegranate extract was able to supplement and improve the treatment outcomes of the GnRH analog therapy for ICPP in Chinese girls.

Changes in brain peptides associated with reproduction and energy homeostasis in photosensitive and photorefractory migratory redheaded buntings.

Present study examined the expression of brain peptides associated with the reproduction and energy homeostasis (GnRH/GnIH, NPY/VIP), and assessed their possible functional association in the photosensitive (non-breeding, pre-breeding), photostimulated (breeding) and photorefractory (post-breeding) migratory redheaded buntings (Emberiza bruniceps), using double-labeled immunohistochemistry. Particularly, we measured immunoreactive (-ir) cell numbers, per cent cell area and cell optical density (OD) in the preoptic area (GnRH-I), midbrain (GnRH-II), paraventricular nucleus (GnIH), dorsomedial hypothalamus, DMH and infundibular complex, INc (NPY and VIP), and lateral septal organ (VIP) of buntings kept under natural photoperiods at the wintering latitude (26°55'N). There was a significant seasonal difference in GnRH-I, not GnRH-II, with reduced -ir cells in the photosensitive and photorefractory buntings, and notably with increased cell OD between the refractory and non-breeding states with no increase in testis size. Also, increased cell OD of GnIH neurons in non-breeding state indicated its role in the maintenance of small testes during the post-refractory period. Overall, seasonal changes in GnRH-I and GnIH were found consistent with their suggested roles in reproductive regulation of absolute photorefractory birds. Further, there was a significant seasonal change in cell OD of NPY neurons in DMH, not the INc. In contrast, VIP immunoreactivity was seasonally altered, with a significantly higher VIP-ir cells in breeding than the pre-breeding state. Finally, close proximity between perikarya with fibres suggested functional interactions between the GnRH and GnIH, and NPY and VIP. Thus, seasonal plasticity of brain peptides is perhaps the part of neural regulation of seasonal reproduction and associated energy homeostasis in migratory songbirds.

Premenstrual syndrome: A mini review.

Premenstrual syndrome (PMS) is characterized by recurrent, moderate-to-severe affective, physical, and behavioral symptoms that develop during the luteal menstrual cycle and disappear within a few days of menstruation. Premenstrual dysphoric disorder (PMDD) is a severe and disabling condition that can affect personal relationships and occupational activities. PMS occurs in 30-40% of reproductive-age females; PMDD affects 3-8% of this population. Although the etiology of PMS is unclear, several theories suggest increased sensitivity to normal hormonal changes and neurotransmitter abnormalities. The diagnostic method of PMS is the Daily Record of Severity of Problems, which women with PMS can use to self-report several symptoms and their severity. Although combined oral contraceptives and serotonergic antidepressants are effective drugs, each is a different option for treating PMS/PMDD. Serotonergic antidepressants are the drugs of choice for improving both physical and mood symptoms. Combined oral contraceptives appear to primarily improve physical symptoms. Clinicians should consider each patient's situation individually. Other treatment options include lifestyle modification, cognitive behavioral therapy, and herbal medicine (e.g., chasteberry).

Comparison of the effects of Origanum vulgare with LHRH-A2 and 17ß-estradiol on the ultrastructure of gonadotroph cells and ovarian oogenesis in immature Trichogaster trichopterus.

Origanum vulgare is a plant of the mint family that contains phytoestrogens. This study compared the effects of O. vulgare, LHRH-A2, and 17ß-estradiol on the ultrastructure of gonadotroph cells and ovarian oogenesis in immature Trichogaster trichopterus. Fish (5.1±0.032cm and 2.1±0.043g, n=150) were randomly divided into four treatment groups (three hormonal treatments and control) and treated intramuscularly at four levels with 17ß-estradiol or O. vulgare at 10, 20, 30 and 50mg/kg body weight and with LHRH-A2 at 0.001, 0.002, 0.003, and 0.005mg/kg body weight. There were three control treatments: saline, ethanol and placebo. Fish were kept in 15 tanks, with 10 fish per tank, injected a total of seven doses over 13 days. Gonadosomatic index (GSI) and oocyte diameter were lower (P≤0.05) in the control than in the three hormonal treatments. The highest GSI and oocyte diameter responses were observed in fish treated with 17ß-estradiol (2.76±0.23%, 149.8±15.43mm) followed by O. vulgare (1.86±0.18%, 104.3±11.5mm) and LHRH-A2 (1.52±0.12%, 91.75±9.02mm) (P≤0.05). Moreover, there was a significant effect of dose level within all the hormonal treatments (P≤0.05). The effect of treatment on the length and weight was likely GSI. Ovarian tissue results showed faster oogenesis of oocytes in fish treated with O. vulgare, after 17ß-estradiol. Ultrastructure of gonadotroph cells demonstrated less stimulation by O. vulgare than by 17ß-estradiol and LHRH-A2. This study suggests that compared with the two hormonal treatments, O. vulgare dose-dependently affects ovarian oogenesis and gonadotroph cells.

LH-Independent Testosterone Secretion Is Mediated by the Interaction Between GNRH2 and Its Receptor Within Porcine Testes.

Unlike classic gonadotropin-releasing hormone 1 (GNRH1), the second mammalian isoform (GNRH2) is an ineffective stimulant of gonadotropin release. Species that produce GNRH2 may not maintain a functional GNRH2 receptor (GNRHR2) due to coding errors. A full-length GNRHR2 gene has been identified in swine, but its role in reproduction requires further elucidation. Our objective was to examine the role of GNRH2 and GNRHR2 in testicular function of boars. We discovered that GNRH2 levels were higher in the testis than in the anterior pituitary gland or hypothalamus, corresponding to greater GNRHR2 abundance in the testis versus the anterior pituitary gland. Moreover, GNRH2 immunostaining was most prevalent within seminiferous tubules, whereas GNRHR2 was detected in high abundance on Leydig cells. GNRH2 pretreatment of testis explant cultures elicited testosterone secretion similar to that of human chorionic gonadotropin stimulation. Treatment of mature boars with GNRH2 elevated testosterone levels similar to those of GNRH1-treated males, despite minimal GNRH2-induced release of luteinizing hormone (LH). When pretreated with a GNRHR1 antagonist (SB-75), subsequent GNRH2 treatment stimulated low levels of testosterone secretion despite a pattern of LH release similar to that in the previous trial, suggesting that SB-75 inhibited testicular GNRHR2s. Given that pigs lack testicular GNRHR1, these data may indicate that GNRH2 and its receptor are involved in autocrine or paracrine regulation of testosterone secretion. Notably, our data are the first to suggest a biological function of a novel GNRH2-GNRHR2 system in the testes of swine.

Hypothalamic gonadotropin-releasing hormone (GnRH) receptor neurons fire in synchrony with the female reproductive cycle.

Gonadotropin-releasing hormone (GnRH) controls mammalian reproduction via the hypothalamic-pituitary-gonadal (hpg) axis, acting on gonadotrope cells in the pituitary gland that express the GnRH receptor (GnRHR). Cells expressing the GnRHR have also been identified in the brain. However, the mechanism by which GnRH acts on these potential target cells remains poorly understood due to the difficulty of visualizing and identifying living GnRHR neurons in the central nervous system. We have developed a mouse strain in which GnRHR neurons express a fluorescent marker, enabling the reliable identification of these cells independent of the hormonal status of the animal. In this study, we analyze the GnRHR neurons of the periventricular hypothalamic nucleus in acute brain slices prepared from adult female mice. Strikingly, we find that the action potential firing pattern of these neurons alternates in synchrony with the estrous cycle, with pronounced burst firing during the preovulatory period. We demonstrate that GnRH stimulation is sufficient to trigger the conversion from tonic to burst firing in GnRHR neurons. Furthermore, we show that this switch in the firing pattern is reversed by a potent GnRHR antagonist. These data suggest that endogenous GnRH acts on GnRHR neurons and triggers burst firing in these cells during late proestrus and estrus. Our data have important clinical implications in that they indicate a novel mode of action for GnRHR agonists and antagonists in neurons of the central nervous system that are not part of the classical hpg axis.

Effect of azaline B on follicular development and functions in the hamster.

The usefulness of azaline B, a GnRH antagonist, in suppressing gonadotropin secretion in the golden hamster was examined by examining follicular development, steroidogenesis and expression of steroidogenic enzymes. Serum levels of P and E declined significantly, while FSH or LH was undetectable in azaline B-treated hamsters. FSH significantly increased serum E levels, whereas LH upregulated serum P levels. The formation of antral follicles ceased in azaline-treated hamsters, but was reversed by FSH with or without LH supplement. FSH also activated the primordial follicle pool resulting in increased formation of primary and preantral follicles. Further, an increasing trend in the formation of preantral follicles in response to E or E + P, and the formation of antral follicles in response to E + P treatment was evident. The level of Cyp11a1 mRNA increased markedly in LH- or LH + FSH-treated hamsters, whereas FSH with or without LH upregulated Cyp17a1, Cyp19a1 and Fshr mRNA expression. E without or with P also upregulated ovarian Cyp19a1 mRNA expression. The expression of enzyme protein corroborated the mRNA data. In summary, azaline B is an efficient GnRH antagonist in the hamster, and will be useful in studying the selective effect of gonadotropins on ovarian functions without disrupting the physiological functions of other hormones in ovarian cells.

Protection of ovarian function during chemotherapy for ovarian cancer.

The protection of ovarian function during chemotherapy is an urgent issue to be resolved after the fertility preserving surgery on patients with ovarian cancer. The paper summarizes and analyzes the research progress on the protective measures in the aspects of gonadotropin releasing hormone analogue (GnRHa), cell protecting agents, and traditional Chinese medical science and drugs.