Follicle-stimulating Hormone Release Research Articles

GHR106 Monoclonal Antibody is Bioequivalent to GnRH Peptide Analogs

GnRH (gonadotropin releasing hormone) is a decapeptide hormone and was discovered initially to react with GnRH receptor in the anterior pituitary. This hormone serves to stimulate the release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) for the differentiation and maturations of reproductive functions. Due to the relative short half-life of GnRH (in min) in circulations, numerous peptide analogs were made available to increase the half-life of these GnRH analogs to hours. Due to structural modifications, they were classified into either agonists or antagonists, depending on their respective biological actions [1-3].

Reproductive hormonal variations and adenohypophyseal lesions in pre-pubertal buffalo heifers inoculated with Pasteurella multocida type B: 2 and its immunogens

BackgroundHemorrhagic septicemia is a fatal disease of cattle and buffaloes caused by P. multocida. Although the pathogenesis of the bacteria has been well established in literature, there is a paucity of information on the possible role of the bacteria and its immunogens; lipopolysaccharide (LPS) and outer membrane proteins (OMPs) on the reproductive capacity of buffalo heifers.MethodsIn this study, twenty one healthy prepubertal female buffaloes aged 8 months were divided into seven groups of 3 buffaloes each (G1-G7). Group 1 (G1) served as the negative control group and were inoculated orally with 10 mL sterile Phosphate Buffer Saline (PBS), groups 2 (G2) and 3 (G3) were inoculated orally and subcutaneously with 10 mL of 1012 colony forming unit (cfu) of P.multocida type B: 2, while groups 4 (G4) and 5 (G5) received 10 mL of bacterial LPS orally and intravenously, respectively. Lastly, groups 6 (G6) and 7 (G7) were orally and subcutaneously inoculated with 10 mL of bacterial OMPs. Whole blood was collected in EDTA vials at stipulated time points (0, 2, 4, 6, 8, 10, 12, 24, 36, 48, 72, 120, 168, 216, 264, 312, 360, 408, 456 and 504 h), while tissue sections of the pituitary glands were collected and transported to the histopathology laboratory in 10% buffered formalin for processing and Hematoxylin and eosin staining. Plasma levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), progesterone (PG), estradiol (EST) and gonadotrophin releasing hormone (GnRH) were determined.ResultsThe histopathological lesions observed in the pituitary gland included hemorrhage, congestion, inflammatory cell infiltration, hydropic degeneration, necrosis and edema. These changes were higher (p < 0.05) in distribution and severity in G3, G6 and G7. Hormonal concentrations of LH, FSH, PG, EST and GnRH declined in all inoculation groups as time elapsed and were lower (p < 0.05) than that of the control group.ConclusionBased on these findings, P.multocida B: 2 and its immunogens can be said to negatively affect the hypothalamic-pituitary-gonadal axis, resulting in decreased levels of reproductive hormones which may predispose to infertility in buffalo heifers.

New gonadotropin-releasing hormone glycolipids with direct antiproliferative activity and gonadotropin-releasing potency

Gonadotropin-releasing hormone (GnRH) is an endogenous peptide with a short biological half-life. Although GnRH analogs (eg. triptorelin) are developed with enhanced stability compared to the native peptide, they still suffer from poor biological stability and pharmacokinetic properties. Furthermore, they are only effective in the treatment of hormone-dependent reproductive cancers. In this study we applied lipidation and glycosylation along with D-amino acid substitution at position 6 (D-Trp 6 ) to improve the stability, permeability, and consequently the potency of the GnRH peptide and triptorelin. We showed that the conjugation of GnRH with a lipid moiety and carbohydrates made all modified constructs ( 1– 8 ) more stable than the parent peptide against enzymatic degradation (5.5–6.5 times). Two of the lactose-modified glycolipopeptides, 3 and 6 , showed 27 and 16 times higher membrane permeability than the parent GnRH, respectively. All analogs with D-Trp 6 -substitution ( 4–6 ) exerted GnRH receptor-mediated antiproliferative activity in prostate and ovarian GnRH-receptor positive cell lines. They were more potent than triptorelin in the hormone-independent prostate cancer cell line: DU145. Compound 6 (lactose-modified) was the most potent analog for stimulating the release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) gonadotropins from rat pituitary cells in vitro . The same glycolipopeptide exhibited a higher efficacy and duration of action in stimulating the release of LH than triptorelin in a preclinical mouse model. The superior activity of lipid- and carbohydrate-substituted triptorelin analog 6 made it a promising candidate for the development of new GnRH agonists to treat both hormone-dependent and hormone-refractory prostate cancer.

THE NOVEL BIOSIMILAR OF FOLLITROPIN ALPHA TO BE MANUFACTURED IN RUSSIA STARTING FROM 2017

Within the framework of the 27th international conference «Reproductive technologies today and tomorrow», the first Russia-made follitropin alfa biosimilar for controlled ovarian stimulation in assisted reproductive technologies (ART) was presented. The follicle-stimulating hormone (FSH) biosimilar has undergone all stages of development in Russia, from the producer cells culture to the release of active FSH. Also the data are presented on a prospective randomized crossover study of phase I confirming the similarity of pharmacokinetics between the biosimilar and the original FSH. Another randomized multicenter phase III clinical study is now under way aiming to demonstrate the clinical equivalence between the biosimilar and the original FSH; preliminary results of this study are presented and discussed. As planned, the recombinant FSH biosimilar will be produced in disposable injectors (pen-injector) that provide easy-to-use handling, convenient dose setting and wide range dosing.

Transdermal testosterone pretreatment in poor responders undergoing ICSI: a randomized clinical trial.

Does pretreatment with transdermal testosterone increase the number of cumulus-oocyte complexes (COCs) retrieved by more than 1.5 in poor responders undergoing intracytoplasmic sperm injection (ICSI), using recombinant follicle stimulating hormone (FSH) and gonadotrophin releasing hormone agonists (GnRHa)? Testosterone pretreatment failed to increase the number of COCs by more than 1.5 as compared with no pretreatment in poor responders undergoing ICSI (difference between medians: 0.0, 95% CI: -1.0 to +1.0). Androgens are thought to play an important role in early follicular development by enhancing ovarian sensitivity to FSH. In a recent meta-analysis, testosterone pretreatment resulted in an increase of 1.5 COCs as compared with no pretreatment. However, this effect was based on the analysis of only two randomized controlled trials (RCTs) including 163 patients. Evidently, there is a need for additional RCTs that will allow firmer conclusions to be drawn. The present RCT was designed to detect a difference of 1.5 COCs (sample size required = 48 patients). From 02/2014 until 04/2015, 50 poor responders fulfilling the Bologna criteria have been randomized (using a randomization list) to either testosterone pretreatment for 21 days ( ITALIC! n = 26) or no pretreatment ( ITALIC! n = 24). All patients underwent a long follicular GnRHa protocol. Recombinant FSH stimulation was started on Day 22 following GnRHa initiation. In the testosterone pretreatment group, a daily dose of 10 mg of testosterone gel was applied transdermally for 21 days starting from GnRHa initiation. Results are expressed as median (interquartile range). No differences in baseline characteristics were observed between the two groups compared. Testosterone levels [median (interquartile range)] were significantly higher in the testosterone pretreatment on the day of initiation of FSH stimulation [114 (99.5) ng/dl versus 20 (20) ng/dl, respectively, ITALIC! P < 0.001]. Duration of FSH stimulation [median (interquartile range)] was similar between the groups compared [12.5 (3.0) days versus 12 (3.0) days, respectively, ITALIC! P = 0.52]. The number of COCs retrieved [median (interquartile range)] was not different between the testosterone pretreatment and the no pretreatment groups [3.5 (4.0) versus 3.0 (3.0), 95% CI for the median: 2.0-5.0 versus 2.7-4.3, respectively; difference between medians: 0.0, 95% CI: +1.0 to -1.0). Similarly no differences were observed regarding fertilization rates [median (interquartile range)] [66.7% (32.5) versus 66.7% (42.9), respectively, ITALIC! P = 0.97] and live birth rates per randomized patient (7.7% versus 8.3%, respectively, rate difference: -0.6%, 95% CI: -19.0 to +16.9). The study was not powered to detect differences less than 1.5 COCs, although it is doubtful whether these differences would be clinically relevant. Moreover, due to sample size restrictions, no conclusions can be drawn regarding the probability of live birth. The results of this randomized clinical trial, suggesting that pretreatment with 10 mg of transdermal testosterone for 21 days does not improve ovarian response by more than 1.5 oocytes, could be used to more accurately consult patients with poor ovarian response. However, an improvement in IVF outcome using a higher dose of testosterone or a longer pretreatment period cannot be excluded. The study was partially funded by a Scholarship from the Academy of Athens. C.A.V. reports personal fees and non-financial support from Merck, Sharp and Dome, personal fees and non-financial support from Merck Serono, personal fees and non-financial support from IPSEN Hellas S.A., outside the submitted work. B.C.T. reports grants from Merck Serono, grants from Merck Sharp & Dohme, personal fees from Merck Serono, personal fees from Merck Sharp & Dohme, personal fees from IBSA & Ferring, outside the submitted work. NCT01961336. 10 October 2013. 02/2014.

The physiology of functional hypothalamic amenorrhea associated with energy deficiency in exercising women and in women with anorexia nervosa.

An energy deficiency is the result of inadequate energy intake relative to high energy expenditure. Often observed with the development of an energy deficiency is a high drive for thinness, dietary restraint, and weight and shape concerns in association with eating behaviors. At a basic physiologic level, a chronic energy deficiency promotes compensatory mechanisms to conserve fuel for vital physiologic function. Alterations have been documented in resting energy expenditure (REE) and metabolic hormones. Observed metabolic alterations include nutritionally acquired growth hormone resistance and reduced insulin-like growth factor-1 (IGF-1) concentrations; hypercortisolemia; increased ghrelin, peptide YY, and adiponectin; and decreased leptin, triiodothyronine, and kisspeptin. The cumulative effect of the energetic and metabolic alterations is a suppression of the hypothalamic-pituitary-ovarian axis. Gonadotropin releasing hormone secretion is decreased with consequent suppression of luteinizing hormone and follicle stimulating hormone release. Alterations in hypothalamic-pituitary secretion alters the production of estrogen and progesterone resulting in subclinical or clinical menstrual dysfunction.

Oral Presentation VIII

ABSTRACT BACKGROUND AND AIMS Activin, a member of the transforming growth factor beta protein family, was originally isolated from gonadal fluids and stimulates the release of pituitary follicle-stimulating hormone (FSH). Activin has numerous functions in both normal and neoplastic cells. Although it was suggested that gonadal tissue is the primary site of activin production, several extragonadal sources have subsequently been identified, including human thyrocytes. METHODS In our study, serum levels of activin A were measured by chemiluminescence, and the expression of receptors of activin A in thyroid tissue was detected by immunohistochemistry in female patients with thyroid papillary cancer [stage I (n = 60), stage II (n = 60), stage III (n = 60), stage IV (n = 60)] and in normal controls (n = 60). RESULTS The serum levels of activin A were no significantly different between patients with thyroid papillary cancer and normal controls as well as different stages. But the expressions of receptors of activin A were greater in patients with thyroid papillary cancer than in normal controls. And the positive rates of receptor expression were significantly more in stage III and IV than in stage I and II. CONCLUSION In conclusion, this study demonstrates that serum levels of activin A undergo no significant changes when thyroid papillary cancer occurs. The thyroid gland is not the predominant source of activin A. The expressions of receptors of activin A were significantly greater in patients with thyroid papillary cancer than in normal controls. And the positive rates of receptor expressions were associated with the severity of cancer. Because activin A may exert negative action on thyrocyte proliferation, it is conceivable that the increase in the receptor of activin A in thyroid papillary cancer might represent a counteracting mechanism.

Disrupting the circadian photo-period alters the release of follicle-stimulating hormone, luteinizing hormone, progesterone, and estradiol in maternal and fetal sheep.

Although a large number of studies show that photo-period disruption potentially affects hormone secretion in mammals, information about the effects of circadian photo-period disruption during pregnancy on fetal blood reproductive hormone levels is scarce. This study used ewes and their fetuses to determine the effects of circadian photo-period disruption (deprivation of darkness) on follicle-stimulating hormone, luteinizing hormone, estradiol, and progesterone in maternal and fetal circulation at late gestation. Pregnant ewes (gestational age: 135 ± 3 days) were randomly placed into control and dark deprivation groups. The control (N = 5) and dark deprivation (N = 5) groups were exposed to a fixed 12 h light/12 h dark cycle and a 24 h constant light cycle, respectively, for 2 days. Dark deprivation up-regulated follicle-stimulating hormone and estradiol levels and down-regulated progesterone levels in both maternal and fetal circulation, and up-regulated luteinizing hormone levels in fetal but not maternal circulation. These results provide new information about how circadian photo-period disruption during pregnancy could alter the release of certain reproductive hormones into fetal blood, which may influence the development of fetal organs in utero, as well as long-term health.

Sequence analysis, tissue distribution and molecular physiology of the GnRH preprogonadotrophin in the South American plains vizcacha (Lagostomus maximus)

Gonadotropin-releasing hormone (GnRH) is the regulator of the hypothalamic-hypophyseal-gonadal (HHG) axis. GnRH and GAP (GnRH-associated protein) are both encoded by a single preprohormone. Different variants of GnRH have been described. In most mammals, GnRH is secreted in a pulsatile manner that stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The South-American plains vizcacha, Lagostomus maximus, is a rodent with peculiar reproductive features including natural poly-ovulation up to 800 oocytes per estrous cycle, pre-ovulatory follicle formation throughout pregnancy and an ovulatory process which takes place at mid-gestation and adds a considerable number of secondary corpora lutea. Such features should occur under a special modulation of the HHG axis, guided by GnRH. The aim of this study was to sequence hypothalamic GnRH preprogonadotrophin mRNA in the vizcacha, to compare it with evolutionarily related species and to identify its expression, distribution and pulsatile pattern of secretion. The GnRH1variant was detected and showed the highest homology with that of chinchilla, its closest evolutionarily related species. Two isoforms of transcripts were identified, carrying the same coding sequence, but different 5′ untranslated regions. This suggests a sensitive equilibrium between RNA stability and translational efficiency. A predominant hypothalamic localization and a pulsatile secretion pattern of one pulse of GnRH every hour were found. The lower homology found for GAP, also among evolutionarily related species, depicts a potentially different bioactivity.

Hydrogen-rich saline attenuates chemotherapy-induced ovarian injury via regulation of oxidative stress.

Hydrogen has been reported to exert a therapeutic effect in several diseases due to its antioxidative, anti-inflammatory and anti-apoptotic properties. The aim of the present study was to investigate whether hydrogen-rich saline treatment could attenuate ovarian damage induced by cisplatin. A total of 240 adult, virgin, female Sprague Dawley rats, weighing 180-220 g, were randomly divided into four groups (n=60 per group): Control (Con), control + hydrogen-rich saline (Con + H2), cisplatin-induced ovarian injury (OI) and cisplatin-induced ovarian injury + hydrogen-rich saline (OI + H2). Cisplatin was diluted in saline immediately before use. In the OI and OI + H2 groups, the rats were administered a dose of cisplatin on the 1st and 7th days. The rats in the Con + H2 and OI + H2 groups were intraperitoneally injected with hydrogen-rich saline (10ml/kg body weight) once a day over a 2-week period. On the 14th, 28th and 42nd days (T1, T2 and T3) after the cisplatin injection, femoral vein blood was collected. At the end of the experiment, ovarian homogenates were prepared, and the samples were used for estrogen (E2), follicle-stimulating hormone (FSH), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) examination. In addition, rats (n=10 per group) were sacrificed for bilateral ovary removal; one was fixed in formalin for follicle-counting analysis, while the other was used for nuclear factor erythroid 2-related factor 2 (Nrf2) detection by western blotting. Hydrogen-rich saline attenuated the FSH release, elevated the level of E2, improved the development of follicles, and reduced the damage to the ovarian cortex at T1, T2 and T3 in the OI + H2 rats. Cisplatin induced oxidative stress by increasing the levels of oxidation products and attenuating the activity of antioxidant enzyme, which could be reversed by hydrogen-rich saline treatment. Furthermore, hydrogen-rich saline regulated the Nrf2 protein expression in rats with ovarian damage. In conclusion, hydrogen-rich saline exerts a protective effect against cisplatin-induced ovarian injury by reducing MDA and increasing SOD and CAT activity. Ovarian injury induced by chemotherapy involves the activation of Nrf2.

Kiss2 as a Regulator of Lh and Fsh Secretion via Paracrine/Autocrine Signaling in the Teleost Fish European Sea Bass (Dicentrarchus labrax).

Kisspeptins are key players in the neuroendocrine control of puberty and other reproductive processes in mammals. Several studies have demonstrated that the KISS/GPR54 system is expressed by gonadotrophs, but in vitro studies assessing the direct stimulatory effects of kisspeptin on gonadotropin secretion in the pituitary have provided conflicting results. In this study, we investigated whether kisspeptin directly influences the reproductive function of sea bass pituitary. First, the highly active peptides Kiss1-15 and Kiss2-12 were used to stimulate dispersed sea bass pituitary cells obtained from mature males. Our results show that, first, Kiss2-12 induced luteinizing hormone (Lh) and follicle-stimulating hormone (Fsh) release, whereas Kiss1-15 had no effect on gonadotropin secretion at full spermiation stage. Second, the distribution and nature of Kiss2 and its potential interactions with the gonadotropin-releasing hormone 1 (Gnrh1) system in the pituitary were analyzed using dual fluorescence immunohistochemistry. Kiss2 cells were found in the proximal pars distalis and colocalized with gonadotropin-immunoreactive cells. In summary, our results provide, for the first time in a teleost species, functional and neuroanatomical evidence that Kiss2 may act through different routes to directly modulate the activity of gonadotrophs, either as a hypophysiotropic neuropeptide or as an autocrine/paracrine factor.

The immunoregulatory and fibrotic roles of activin A in allergic asthma.

Activin A, a member of the TGF-β superfamily of cytokines, was originally identified as an inducer of follicle stimulating hormone release, but has since been ascribed roles in normal physiological processes, as an immunoregulatory cytokine and as a driver of fibrosis. In the last 10–15 years, it has also become abundantly clear that activin A plays an important role in the regulation of asthmatic inflammation and airway remodelling. This review provides a brief introduction to the activin A/TGF-β superfamily, focussing on the regulation of receptors and signalling pathways. We examine the contradictory evidence for generalized pro- vs. anti-inflammatory effects of activin A in inflammation, before appraising its role in asthmatic inflammation and airway remodelling specifically by evaluating data from both murine models and clinical studies. We identify key issues to be addressed, paving the way for safe exploitation of modulation of activin A function for treatment of allergic asthma and other inflammatory lung diseases.

Activity of the porcine gonadotropin-releasing hormone receptor gene promoter is partially conferred by a distal gonadotrope specific element (GSE) within an upstream enhancing region, two proximal GSEs and a retinoid X receptor binding site.

BackgroundRegulation of gonadotropin-releasing hormone (GnRH) receptor (GnRHR) numbers on gonadotropes within the anterior pituitary gland represents a critical point for control of reproductive function. Binding of GnRH to its receptor regulates follicle stimulating hormone (FSH) and luteinizing hormone (LH) release and levels of this G-protein coupled receptor on the surface of gonadotropes determines their sensitivity to GnRH pulses. While transcriptional regulation of this gene has been studied in mice, rats, humans and sheep, little is known about its regulation in the pig, an important agricultural species and human research model.MethodsWe isolated 5118 bp of 5′ flanking sequence for the porcine GnRHR gene and generated luciferase reporter vectors. Deletion and mutation constructs were evaluated in gonadotrope-derived alphaT3-1 cells to determine regions important for gene transcription. Additionally, electrophoretic mobility shift assays (EMSAs) were performed to identify transcription factors binding to the GnRHR promoter.ResultsTransient transfections revealed that the GnRHR promoter was functional in alphaT3-1 cells but not in cells of non-gonadotrope origin. Mutation of the highly conserved gonadotrope specific element (GSE) located at -179/-171 of proximal promoter completely ablated luciferase activity, whereas mutation of another GSE at -315/-310 reduced activity by 34%. Consistent with this, EMSAs using alphaT3-1 nuclear extracts and a steroidogenic factor (SF)1 antibody confirmed SF1 binding to both GSEs. EMSAs also demonstrated that a retinoid X receptor (RXR) binding site at -279/-274 binds RXRalpha and RXRbeta and mutation of this site eliminated promoter activity. Transient transfection of alphaT3-1 cells with reporter vectors containing selective removal of 5′ flanking region for the porcine GnRHR gene indicated that the -1915/-1431 segment was important for promoter activity. Definition of this region via transfection assays and EMSAs revealed an upstream enhancing region located at -1779/-1667 that increases porcine GnRHR gene expression in alphaT3-1 cells and includes a SF1 binding site at -1760/-1753.ConclusionsPorcine GnRHR promoter activity in alphaT3-1 cells is partially conferred by a distal GSE, two proximal GSEs and a RXR binding site. Basal gonadotrope expression of the porcine GnRHR gene uniquely involves three GSEs and RXR is newly identified as a regulator of GnRHR promoter activity.

Growth hormone, luteinizing hormone, and follicle-stimulating hormone regulation by neuropeptide Y in both sexes of the cichlid fish, Cichlasoma dimerus.

Neuropeptide Y (NPY) is considered the most potent orexigenic peptide, increasing before meal time and during fasting. In teleost, most studies on NPY action upon growth hormone (GH) and luteinizing hormone (LH) were conducted in females or group of animals without sex discrimination. The aim of this study was to evaluate whether NPY modulates the expression and release of GH and gonadotropins in both sexes of Cichlasoma dimerus. By double-label immunofluorescence, we first determined the association between NPY fibers and pituitary cells. In addition, we performed in vitro studies to evaluate the effect of NPY on GH and gonadotropins expression by real-time PCR, and release by Western blot, in males and females separately. Contacts between NPY fibers and GH and follicle-stimulating hormone (FSH)-producing cells were detected, indicating possible functional relationships. We observed an increase in GH release in the culture medium at 2 nM for males (p = 0.043) and 20 nM for females (p = 0.028). Pituitary FSH release was stimulated at 20 nM (p = 0.026) and 200 nM (p = 0.033) for males and females, respectively. Finally, NPY only increased β-LH mRNA expression at 20 nM in females (p = 0.028) and its release at 2 nM (p = 0.049) and 200 nM for males (p = 0.005) and 200 nM for females (p = 0.018). In conclusion, NPY acts as a GH-, LH- and FSH-releasing factor, in a dose- and sex-dependent way.

Adiponectin expression in the porcine pituitary during the estrous cycle and its effect on LH and FSH secretion.

Female reproductive success is closely associated with nutritional status and energy balance. In this context, adiponectin appears to be a key hormone connecting reproductive system function and metabolism regulation. It is hypothesized that adiponectin expression in the pituitary depends on the phase of the estrous cycle. The effect of adiponectin on luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion is also postulated. Changes in the adiponectin gene and protein expression in the porcine anterior (AP) and posterior (NP) pituitaries as well as the effect of in vitro administration of adiponectin on basal and gonadotropin-releasing hormone (GnRH)- and/or insulin-stimulated LH and FSH secretion were investigated on days 2-3, 10-12, 14-16, and 17-19 of the estrous cycle. Adiponectin gene was more pronounced on days 2-3 in AP but on days 10-12 in NP. Protein concentration in AP was the highest on days 10-12 and in NP on days 10-12 and 17-19 of the cycle. In vitro, adiponectin did not affect basal LH secretion but increased FSH release by AP cells. Adiponectin administration affected GnRH- and/or insulin-induced LH and FSH output in a manner dependent on the phase of the estrous cycle. In this study we indicated for the first time adiponectin expression in the porcine AP and NP that was dependent on the phase of the estrous cycle. In vitro studies indicated that adiponectin may affect gonadotropin secretion. The above suggests that the studied adipokine may influence female reproductive functions via its effect on LH and FSH secretion by gonadotrophs, but the cellular mechanism of its action remains unknown.

Characterization of tilapia (Oreochromis niloticus) gonadotropins by modeling and immunoneutralization

In fish, both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) play important roles in reproduction. Here we explored the structure and differential specificity of tilapia (t) gonadotropins (GTHs) to delineate their physiological relevance and the nature of their regulation. We generated structural models of tGTHs and GTH receptors (R) that enabled us to better understand the hormone–receptor interacting region. In tilapia, FSH release is under the control of the hypothalamic decapeptide GnRH, an effect that was abolished by specific bioneutralizing antisera [anti-recombinant (r) tFSHβ]. These antisera also reduced the basal secretion and delayed GnRH-stimulated production of 11-ketotestosterone (11KT), and dramatically reduced LH levels. Immunoneutralization of tLH using anti-rtLHβ significantly reduced its GnRH-stimulated levels. Basal 11KT and FSH levels were also reduced. Taken together, these results suggest a feedback mechanism between FSH and LH release in tilapia.

Suppression of fertility in adult cats.

Cats are animals with highly efficient reproduction, clearly pointing to a need for suppression of fertility. Although surgical contraception is highly effective, it is not always the method of choice. This is predominantly because it is cost-intensive, time-consuming and irreversible, with the latter being of major importance for cat breeders. This article reviews the use of progestins, scleroting agents, immunocontraception, melatonin, GnRH antagonists and finally, GnRH agonists, in adult male and female cats in detail, according to the present state of the art. By now, various scientific and clinical options are available for the suppression of fertility in adult cats and the decision as to which should be chosen - independent of the legal registration of any state - depends on different facts: (i) feral or privately owned animal? (ii) temporary or permanent suppression of fertility wanted/needed? (iii) sex of the animal? New effective and available methods for hormonal contraception include melatonin implants for short-term post ponement of oestrus in adult queens and slow-release GnRH-agonist implants containing deslorelin (Suprelorin(®) ) for short- and long-term contraception in male and female companion and breeding cats.

Sexual Functions, Sexual Organs and Sex Hormone Level in Chronic Alcohol Intake

A general knowledge among youths is that alcohol enhances sexual desire and sexual performance. In contrast to this, studies have reported various adverse effects of alcohol on reproductive and sexual functions in both male and female. Male alcoholics frequently suffer from erectile dysfunction, intermittent delay in or absence of orgasm, and premature or delayed ejaculation. Alcohol is a toxin that can damage sperm-producing cells in the testicles, decrease testicular size, increase number of abnormally-shaped sperm and lower sperm count. Studies found that heavy alcohol consumption results in reduced testosterone and elevated estrogen levels in the blood and it can decrease the production, release and/or activity of luteinizing hormone and follicle-stimulating hormone. Female alcoholics have problems in producing enough natural lubrication for pain-free sex. Alcohol has a disruptive effect on menstrual cycle which can result in amenorrhea and anovulation. It affects estrogen and progesterone levels and also leads to hyperprolactinemia. It has been observed that when a man stops drinking alcohol, the Review Article British Journal of Medicine & Medical Research, 4(6):1279-1292, 2014 1280 negative effects on fertility and sexual abilities reverse quickly. Long term excessive intake of alcohol can lead to damage to the central nervous system and the peripheral nervous system resulting in loss of sexual desire and infertility in men and women.

Functional analysis of kisspeptin peptides in adult immature chub mackerel (Scomber japonicus) using an intracerebroventricular administration method

In vertebrates (including teleosts), the pivotal hierarchical factor in the control of gonadotropin secretion is the hypothalamic gonadotropin-releasing hormone (GnRH) decapeptide, which regulates the release of pituitary follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Recently, kisspeptins encoded by the Kiss1 gene have been shown to act as upstream endogenous regulators of GnRH neurons in mammals. The chub mackerel (Scomber japonicus) brain expresses two kiss genes (kiss1 and kiss2) that show sexually dimorphic expression profiles during the seasonal gonadal cycle. In the present study, we evaluated the biological potency of kisspeptin peptides to induce transcriptional changes in gnrh1 (hypophysiotropic GnRH form in this species), fshβ and lhβ during the immature stage of adult chub mackerel (2+ years old). Synthetic Kiss1 pentadecapeptide (Kiss1-15) or Kiss2 dodecapeptide (Kiss2-12) at a dose of 100ng were administered into the intracerebroventricular (ICV) region, and brains were sampled at 6 and 12h post-injection. In female fish, gnrh1 levels decreased in the presence of both kisspeptin peptides at 12h post-injection. No significant variation was observed in male fish. In contrast, ICV administration of Kiss2-12 (but not Kiss1-15) significantly increased fshβ and lhβ mRNAs at 12h post-injection compared to a saline injected control in both sexes. These results suggested that synthetic Kiss2-12 could induce transcriptional changes in gnrh1 and gths.

Assessment of protective and anti-oxidant properties of Tribulus terrestris fruits against testicular toxicity in rats.

Aims:This study was carried out to assess the protective and anti-oxidant activities of the methanolic extract of Tribulus terrestris fruits (METT) against sodium valproate (SVP)-induced testicular toxicity in rats.Materials and Methods:Fifty mature male rats were randomly divided into five equal groups (n = 10). Group 1 was used normal (negative) control, and the other four groups were intoxicated with SVP (500 mg/kg–1, orally) during the last week of the experiment. Group 2 was kept intoxicated (positive) control, and Groups 3, 4 and 5 were orally pre-treated with METT in daily doses 2.5, 5.0, and 10.0 mg/kg–1 for 60 days, respectively. Weights of sexual organs, serum testosterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels, semen picture, testicular anti-oxidant capacity and histopathology of testes were the parameters used in this study.Results:Oral pre-treatment with METT significantly increased weights of testes and seminal vesicles; serum testosterone, FSH and LH levels and sperm motility, count and viability in SVP-intoxicated rats. METT enhanced the activity of testicular anti-oxidant enzymes and partially alleviated degenerative changes induced by SVP in testes.Conclusion:The pre-treatment with METT has protective and anti-oxidant effects in SVP-intoxicated rats. Mechanisms of this protective effect against testicular toxicity may be due to the increased release of testosterone, FSH and LH and the enhanced tissue anti-oxidant capacity. These results affirm the traditional use of T. terrestris fruits as an aphrodisiac for treating male sexual impotency and erectile dysfunction in patients. The study recommends that T. terrestris fruits may be beneficial for male patients suffering from infertility.