Gonadotropin-releasing Hormone Antibodies Research Articles

Active immunization with recombinant GnRH6-CRM197 inhibits reproductive function of male rats

Gonadotropin-releasing hormone (GnRH) vaccines have been successfully used for the inhibition of gonadal development and function, but current GnRH-based vaccines often present variability in the response. Cross-reactive material 197 (CRM197) has been used as carrier molecules to enhance an immune response to associated antigens. So, the synthetic mammalian tandem-repeated GnRH hexamer (GnRH6) gene was integrated into the expression plasmid pET-21a. Recombinant GnRH6-CRM197 protein was subsequently overexpressed in Escherichia coli strain BL21 and purified through Nickel column affinity chromatography and the antigenicity and biological effects of GnRH6-CRM197 were evaluated in rats. Sixteen 4-month-old adult male rats were randomly divided into two groups: the GnRH6-CRM197 group (n = 8) and the control group (n = 8). The GnRH6-CRM197 group rats were subcutaneously immunized with 100 μg of GnRH6-CRM197, administered thrice at 2-week intervals with GnRH6-CRM197.The control group received only a white oil adjuvant. Following the initial immunization, the weights of animals were recorded, and blood samples were collected from the orbital sinus at 4, 4.5, 5, 5.5, 6, 6.5, and 7 months. Serum antibody titers and testosterone concentrations were quantified using ELISA and CLIA, respectively. Additionally, testicular tissues were collected for morphological examination. The results revealed a significant increase in serum GnRH antibody titers (p < 0.05), but a significant decrease in serum testosterone concentrations (p < 0.05), and the weight, length, width, and girth of the testis, and the number of spermatogonia cells, spermatocytes, and sperm cells in the immunized rats. Furthermore, seminiferous tubules revealed significant atrophy and no sperm were observed in the immunized animals. Thus, GnRH6-CRM197 may be an effective antigen and a potential immunocastration vaccine.

Effect of GnRH immunocastration on immune function in male rats.

The present study aimed to reveal the effects of immunocastration on the development of the immune system in rats. Seventy rats were randomly assigned into two groups: Control (n = 35) and immunized (n = 35). Twenty-day-old rats were immunized with gonadotropin-releasing hormone (GnRH) and booster immunization was administered every two weeks (three immunizations in total). From 20-day-old rats, we collected samples every two weeks, including five immunized rats and five control rats (seven collections in total). We collected blood samples, testicles, thymuses, and spleens. The results showed that GnRH immunization increased the GnRH antibody titers and reduced the testosterone concentration (both P < 0.05). Compared with the control group, the number of CD4+CD8- cells, CD4-CD8+ cells, and CD4+CD8+ cells increased (P < 0.05) whereas the number of CD4-CD8- cells and CD4+CD25+ cells reduced in the immunized group (P < 0.05) over time. GnRH immunization also increased the relative weights of thymus and spleen (P < 0.05), serum concentrations of interleukin (IL)-2, IL-4, IL-6, IL-10, IL-17 and Interferon-γ (IFN-γ) over time (P < 0.05), and changed the mRNA levels of IL-2, IL-4, IL-6. IL-10, IL-17, IFN-γ, CD4, D8, CD19 GnRH, and GnRH receptor (GnRH-R) in thymus and spleen. Thus, GnRH immunization enhanced the immune markers in thymus, spleen, and blood immune cytokines in rats.

S1002 Association of Irritable Bowel Syndrome and Antibodies Against Endogenous Gonadotropin-releasing Hormone and Its Receptor. a Systematic Review and Meta-analysis

Introduction: Irritable bowel syndrome (IBS) seems to have an unclear pathogenesis in the majority of patients. Antibodies against gonadotropin-releasing hormone (GnRH) have previously been discovered in the blood of these patients on a significant occurrence. This meta- analysis aims to assess if there is a significant association between GnRH antibodies and IBS. Methods: We defined a search strategy and implemented it to the PubMed, Ovid, Scopus and Web of Science databases for English language publications. The data were evaluated for acceptability, and controlled studies, either clinical trials, case control, cross sectional or cohort studies reporting the prevalence of GnRH antibodies in IBS patients were included. RevMan software version 5.4 was used for performing the analysis. Results: The total number of patients in the included studies was 1095 (270 patients in the IBS group, and 825 patients in the control group). By comparing IBS group and control group, we found a statistically significant association between IBS and increased prevalence of GnRH IgM antibodies (RR = 2.29, 95% CI = 1.58 to 3.31, p-value < 0.0001). No heterogeneity was observed among studies (P = 0.20, I2 = 36%). In GnRH receptor IGM antibodies outcome, we found a statistically significant association between IBS and increased prevalence of GnRH IgM antibodies compared with controls (RR = 3.80, 95% CI = 1.72 to 8.38, p-value = 0.0010). No heterogeneity was observed among studies (P = 0.85, I2 = 0%). For GnRH receptor IgM antibodies, the pooled analysis showed a statistically significant association between IBS and increased prevalence of GnRH receptor IgM antibodies compared with controls (RR = 3.80, 95% CI = 1.72 to 8.38, P = 0.0010). No heterogeneity was observed among studies (P = 0.17, I2 = 44%). Conclusion: This current meta-analysis revealed that GnRH IgM Antibodies may have an influence on the development of Irritable bowel syndrome, as Irritable bowel syndrome is related to a higher incidence of IgM antibodies against GnRH and its receptor when compared to healthy persons. More multicenter studies with higher sample sizes are needed to support our findings.

Phage constructs targeting gonadotropin-releasing hormone for fertility control: evaluation in cats.

Phage-gonadotropin-releasing hormone (GnRH) constructs with potential contraceptive properties were generated in our previous study via selection from a phage display library using neutralizing GnRH antibodies as selection targets. In mice, these constructs invoked the production of antibodies against GnRH and suppressed serum testosterone. The goal of this study was to evaluate this vaccine against GnRH for its potential to suppress reproductive characteristics in cats. Sexually mature male cats were injected with a phage-GnRH vaccine using the following treatment groups: (1) single phage-GnRH vaccine with adjuvant; (2) phage-GnRH vaccine without adjuvant and half-dose booster 1 month later; or (3) phage-GnRH vaccine with adjuvant and two half-dose boosters with adjuvant 3 and 6 months later. Anti-GnRH antibodies and serum testosterone, testicular volume and sperm characteristics were evaluated monthly for 7-9 months. All cats developed anti-GnRH antibodies following immunization. Serum antibody titers increased significantly after booster immunizations. In group 3, serum testosterone was suppressed 8 months after primary immunization. Total testicular volume decreased in group 1 by 24-42% and in group 3 by 15-36% at 7 months after immunization, indicating potential gonadal atrophy. Vacuolation of epididymides was observed histologically. Although all cats produced sperm at the conclusion of the study, normal morphology was decreased as much as 38%. Phage alone produced no local or systemic reactions. Immunization of phage with AdjuVac produced unacceptable injection site reactions. Our phage-based vaccine against GnRH demonstrated a potential for fertility impairment in cats. Future research is required to optimize vaccine regimens and identify animal age groups most responsive to the vaccine. If permanent contraception (highly desirable in feral and shelter cats) cannot be achieved, the vaccine has a potential use in zoo animals or pets where multiple administrations are more practical and/or reversible infertility is desirable.

Inactivated Rabies Virus-Vectored Immunocontraceptive Vaccine in a Thermo-Responsive Hydrogel Induces High and Persistent Antibodies against Rabies, but Insufficient Antibodies against Gonadotropin-Releasing Hormone for Contraception.

Rabies is preventable through vaccination, but the need to mount annual canine vaccination campaigns presents major challenges in rabies control and prevention. The development of a rabies vaccine that ensures lifelong immunity and animal population management in one dose could be extremely advantageous. A nonsurgical alternative to spay/neuter is a high priority for animal welfare, but irreversible infertility in one dose has not been achieved. Towards this goal, we developed a rabies virus-vectored immunocontraceptive vaccine ERA-2GnRH, which protected against rabies virus challenge and induced >80% infertility in mice after three doses in a live, liquid-vaccine formulation (Wu et al., 2014). To improve safety and use, we formulated an inactivated vaccine in a thermo-responsive chitosan hydrogel for one-dose delivery and studied the immune responses in mice. The hydrogel did not cause any injection site reactions, and the killed ERA-2GnRH vaccine induced high and persistent rabies virus neutralizing antibodies (rVNA) in mice. The rVNA in the hydrogel group reached an average of 327.40 IU/mL, more than 200 times higher than the liquid vaccine alone. The Gonadotropin-releasing hormone (GnRH) antibodies were also present and lasted longer in the hydrogel group, but did not prevent fertility in mice, reflecting a possible threshold level of GnRH antibodies for contraception. In conclusion, the hydrogel facilitated a high and long-lasting immunity, and ERA-2GnRH is a promising dual vaccine candidate. Future studies will focus on rabies protection in target species and improving the anti-GnRH response.

Effects of active immunization with newly modified GnRH peptides on spermatogenesis and production performance of Holstein bulls.

Immunocastration via vaccination against gonadotropin-releasing hormone (GnRH) is an effective alternative to surgical castration in livestock. In this study, male mice were immunized with eight GnRH peptide derivatives. Two, which exhibited highly significant effects in mice, and one which exhibited the least significant effects were selected for active immunization of 13-month-old bulls. The effects of these GnRH vaccines on sexual development and meat quality in bulls were evaluated by examining testis length, serum hormone and GnRH antibody concentrations, observation of sexual behavior and testicular tissue sections, and evaluation of meat quality indexes. The results indicated that anti-GnRH titers increased rapidly (P<0.05) and serum follicle stimulating hormone, luteinizing hormone, and testosterone concentrations decreased sharply after booster immunization (P<0.05), while testis volumes were lower (P<0.01), testicular growth was arrested and spermatogenesis inhibited in group C GnRH-treated versus control bull groups. Meat quality was not significantly different in immunocastrates relative to bulls in the control group. Our collective results provide a scientific basis to further clarify the mechanisms underlying GnRH-mediated regulation of livestock reproduction, and contribute to the development of an efficient, safe, and reversible immune castration vaccine.

Gonadotropin-releasing hormone immunization and castration in male pigs: effects on growth, hormonal levels, antibody titer response, testicular function, back fat, and consumers' sensory perceptions

This study investigated the effects of gonadotropin-releasing hormone (GnRH) vaccine on pig growth, carcass quality, and sensory perceptions of pork meat by Thai consumers. Male crossbred pigs (n = 30) were separated into three groups of 10 pigs each: boars, immunocastrated pigs, and surgically castrated pigs. The immunocastrated group was immunized at 13 and 19 weeks of age with GnRH vaccine (400 μg/dose). All pigs were slaughtered at 24 weeks of age. Blood samples were collected and testes size determined. Testes weight and back fat thickness were recorded at the time of slaughter, and meat samples were collected for sensory assessment by Thai consumers. Testosterone and progesterone concentration levels decreased significantly two weeks after the second dose of GnRH (p < 0.05), and the GnRH antibody titer of the immunocastrated pigs was significantly high two weeks after the second dose of GnRH (p < 0.05). GnRH vaccine significantly reduced the weight and size of testes. Thai consumers reported no significant differences in odor or flavor among meat samples from the three groups. In conclusion, immunocastration improved growth performance, removed the need for castration surgery, and avoided “boar taint” in the meat. It has also no distinct trace of the boar taint same as pork that is currently produced from physically castrated pig which is making it acceptable to consumers.

Humoral immune responses against gonadotropin releasing hormone elicited by immunization with phage-peptide constructs obtained via phage display

Phage display is based on genetic engineering of phage coat proteins resulting in fusion peptides displayed on the surface of phage particles. The technology is widely used for generation of phages with novel characteristics for numerous applications in biomedicine and far beyond. The focus of this study was on development of phage-peptide constructs that stimulate production of antibodies against gonadotropin releasing hormone (GnRH). Phage-peptide constructs that elicit production of neutralizing GnRH antibodies can be used for anti-fertility and anti-cancer applications. Phage-GnRH constructs were generated via selection from a phage display library using several types of GnRH antibodies as selection targets. Such phage constructs were characterized for sequence similarities to GnRH peptide and frequency of their occurrence in the selection rounds. Five of the constructs with suitable characteristics were tested in mice as a single dose 5×1011 virions (vir) vaccine and were found to be able to stimulate production of GnRH-specific antibodies, but not to suppress testosterone (indirect indicator of GnRH antibody neutralizing properties). Next, one of the constructs was tested at a higher dose of 2×1012 vir per mouse in combination with a poly(lactide-co-glycolide) (PLGA)-based adjuvant. This resulted in multifold increase in GnRH antibody production and significant reduction of serum testosterone, indicating that antibodies produced in response to the phage-GnRH immunization possess neutralizing properties. To achieve optimal immune responses for desired applications, phage-GnRH constructs can be modified with respect to flanking sequences of GnRH-like peptides displayed on phage. Anticipated therapeutic effects also might be attained using optimized phage doses, a combination of several constructs in a single treatment, or application of adjuvants and advanced phage delivery systems.

Effects of a commercial canine gonadotropin releasing hormone vaccine on estrus suppression and estrous behavior in mares

We investigated the effect of immunization against gonadotropin releasing hormone (GnRH) using a commercial canine GnRH vaccine on estrus suppression and unwanted estrous behavior in mares. In experiment 1, mares were immunized (n=6) twice with vaccine (5mL) given intramuscularly 4 weeks apart or received a control diluent (n=5). Transrectal ultrasonographic examination of the reproductive tracts was performed three days a week for 40 weeks after initial vaccination. Blood samples were collected weekly for GnRH antibody titer and progesterone concentration determination. In experiment 2, privately-owned mares (n=12) were immunized twice with vaccine (1mL) given intramuscularly 4 weeks apart. Blood samples were collected prior to each vaccination as well as 12 and 20 weeks after initial treatment, and transrectal ultrasonographic examinations of the reproductive tracts were performed 12 weeks after the first vaccination. Vaccinated mares in experiment 1 responded with a GnRH antibody titer, progesterone concentrations significantly lower than controls, and cessation of ovarian activity. Vaccinated mares in experiment 2 also responded with a GnRH antibody titer, progesterone concentrations that remained basal for the duration of the study, and cessation of ovarian activity. Owners of vaccinated mares in experiment 2 reported that the number of unwanted estrous behaviors present before vaccination significantly decreased following vaccination. In conclusion, GnRH immunization using a canine GnRH vaccine is an effective method for suppressing estrus and unwanted estrous behavior.

Antibodies against gonadotropin-releasing hormone (GnRH) in patients with diabetes mellitus is associated with lower body weight and autonomic neuropathy

BackgroundEsophageal dysmotility and gastroparesis are common secondary complications in patients with diabetes mellitus. Patients with dysmotility express antibodies against gonadotropin-releasing hormone (GnRH) in serum. The aim of the present study was to scrutinize patients with diabetes mellitus with regard to the presence of GnRH antibodies, and to examine associations between antibodies and clinical findings.ResultsThirty-nine consecutive patients with diabetes mellitus were included in the study after clinical examination and examination by esophageal manometry and gastric emptying scintigraphy. Serum was analyzed for the presence of antibodies against GnRH using an ELISA, and values are expressed as relative units (RU). Two age- and gender-matched healthy subjects per each patient served as controls. The prevalence of IgM GnRH antibodies in patients was 33% compared to 14% in controls (p = 0.027), with a higher antibody titer; 1.2 (0.6-5.0) and 0.2 (0.1-0.3) RU, respectively (p = 0.000). The expression of IgG antibodies was 15% in patients and none in controls (p = 0.000). Lower body mass index was associated with the presence of IgM antibodies (OR = 0.835, 95% CI = 0.699–0.998), and autonomic neuropathy with the presence IgG antibodies (OR = 9.000, 95% CI = 1.327–61.025). Esophageal dysmotility (69%) or gastroparesis (18%) were not associated with the presence of IgM antibodies (OR = 0.589, 95% CI = 0.143–2.424 and OR = 3.407, 95% CI = 0.633–18.350, respectively). Neither was esophageal dysmotility associated with IgG antibodies (OR = 2.500, 95% CI = 0.259–24.096).ConclusionsAntibodies against GnRH are more common in patients with diabetes mellitus compared with healthy controls. IgM antibodies are associated with lower body mass index and IgG antibodies are associated with autonomic neuropathy.

Effects of a Commercial Canine Gonadotropin Releasing Hormone Vaccination on Intact Male Llamas and Alpacas

We have investigated the effect of immunization against gonadotropin releasing hormone (GnRH) using a commercial canine GnRH vaccine on testosterone concentration, testicular volume, testicular histology, and intermale behavior in intact male llamas and alpacas. Llamas (n=28) and alpacas (n=20) were either immunized (received 3 mL of vaccine given intramuscularly) or treated as controls (received 3 mL of sterile diluent given intramuscularly) at 0, 3, and 6 weeks. Blood samples and testicular volume measurements were taken at 0, 3, 6, 9, and 12 weeks. Owner surveys grading behavior at 0 and 12 weeks were received for 14 llamas. Two llamas at each time point undergoing the vaccination procedure were also castrated for testicular histological examination. Vaccinated animals elicited a GnRH antibody titer, and there was a significant decrease in testosterone concentration and testicular volume when compared with control animals. Intermale aggressive behavior was also significantly decreased in the surveyed llamas. However, histological examination revealed no significant changes. GnRH immunization using the canine GnRH vaccine may be an effective method for reducing intermale aggression in llamas and alpacas by decreasing circulating testosterone concentrations but cannot be recommended as an immunosterilant because of its lack of efficacy in interrupting spermatogenesis.

Alarelin active immunization influences expression levels of GnRHR, FSHR and LHR proteins in the ovary and enhances follicular development in ewes

We investigated the effects of gonadotropin releasing hormone (GnRH) agonist on expressions of GnRH receptor (GnRHR), follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) proteins in the ovaries and follicular development in the ewes. Forty-two pre-pubertal ewes were assigned to experimental groups 1 to 5 (EG-I to EG-V) and control group (CG). Ewes in EG-I, EG-II and EG-III were subcutaneously injected with 200, 300 or 400 μg alarelin antigens twice (on days 0 and 14), respectively. Ewes in EG-IV and EG-V were subcutaneously injected with 200 μg and 300 μg alarelin antigen four times (on days 0, 7, 14 and 21). Ewes in CG were subcutaneously injected with a solvent twice (on days 0 and 14). Serum concentrations of GnRH antibody in the EGs increased and were higher than (P<0.05) that of CG from day 14 to day 60. GnRH antibody concentrations in EG-IV and EG-V were higher than that in EG-I, EG-II and EG-III from days 35 to 45. Expressions of GnRHR protein in EG-IV and EG-V were lower than that in CG (P<0. 01). Expressions of FSHR and LHR proteins in EGs increased. Levels of FSHR and LHR proteins in EG-IV and EG-V (P<0.05) were higher than CG. Ovarian weights in EGs increased. Values of follicle vertical diameter, follicle transverse diameter, follicle wall thickness, follicle externatheca thickness and follicle internatheca thickness in EG-III and EG-V were greater than other groups. Primordial follicles and primary follicles developed quickly in alarelin-immunized animals. Secondary follicles and mature follicles became more abundant. Mitochondria, mitochondrial cristaes and cortical granules increased. Serum FSH concentrations of EGs remained higher than that in CG from days 28 to 70 (P<0.05). Alarelin immunization stimulated GnRH antibody production, suppressed expression of GnRHR protein, enhanced expressions of FSHR and LHR proteins in ovaries, promoted FSH secretion and thereby accelerated the development of ovaries and follicles in ewes.

Antibodies against Gonadotropin-Releasing Hormone in Patients with Posterior Laryngitis

Patients with functional gastrointestinal disorders express antibodies against gonadotropin-releasing hormone (GnRH) in serum. One common cause of posterior laryngitis (PL) is extra-esophageal reflux, but a functional etiology has also been suggested. The aim of this study was to scrutinize patients with PL with regard to the presence of GnRH antibodies and to examine the association between antibodies and symptoms and reflux. Consecutive PL patients were included after examination. Serum was analyzed for the presence of antibodies using an enzyme-linked immunosorbent assay (ELISA) method and expressed as relative units (RU). Two age- and gender-matched healthy subjects per case served as controls. The prevalence of IgM GnRH antibodies in patients was 35% compared with 28% in controls (P = 0.06), with higher levels in patients (0.8 (0.3–2.2) RU) than in controls (0.2 (0.1–0.6) RU) (P = 0.007). The corresponding IgG antibody prevalences were 43% and 4%, respectively (P = 0.001), with no difference in levels (P = 0.70). There was no association between antibodies and clinical findings.

Gonadotropin-releasing hormone analog buserelin causes neuronal loss in rat gastrointestinal tract

Gonadotropin-releasing hormone (GnRH) analogs are given to women undergoing in vitro fertilization. Case reports describing the development of chronic intestinal pseudo-obstruction and auto-antibodies against GnRH after such treatment suggest a strong association between intestinal dysfunction and GnRH analogs. No experimental model for studying such a relationship is currently at hand. Our main goal was to investigate possible enteric neurodegeneration and titers of GnRH antibodies in response to repeated administration of the GnRH analog buserelin in rat. Rats were treated for 1-4 sessions with daily subcutaneous injections of buserelin or saline for 5 days, followed by 3 weeks of recovery. Buserelin treatment caused significant loss of submucous and myenteric neurons in the fundus, ileum, and colon. The loss of enteric neurons can, at least partly, be explained by increased apoptosis. No GnRH- or GnRH-receptor-immunoreactive (IR) enteric neurons but numerous luteinizing hormone (LH)-receptor-IR neurons were detected. After buserelin treatment, the relative number of enteric LH-receptor-IR neurons decreased, whereas that of nitric-oxide-synthase-IR neurons increased. No intestinal inflammation or increased levels of circulating interleukins/cytokines were noted in response to buserelin treatment. Serum GnRH antibody titers were undetectable or extremely low in all rats. Thus, repeated administrations of buserelin induce neurodegeneration in rat gastrointestinal tract, possibly by way of LH-receptor hyperactivation. The present findings suggest that enteric neurodegenerative effects of GnRH analog treatment in man can be mimicked in rat. However, in contrast to man, no production of GnRH auto-antibodies has been noted in rat.

Physiologic Responses Following Gonadotropin‐Releasing Hormone Immunization in Intact Male Dogs

We investigated the use of a commercial gonadotropin-releasing hormone (GnRH) vaccine as a method of temporary and reversible immunocastration in intact male dogs. Four privately owned dogs were vaccinated twice at 4-week intervals. Blood samples were collected at 0, 4, 12 and 20 weeks following the initial vaccination. These samples were analysed for GnRH antibody titres, luteinizing hormone (LH) and testosterone concentrations. Scrotal measurements were made at the time of sample collection, and testicular volume was calculated using the formula of an ellipsoid. As a result of vaccination, dogs displayed an elevated GnRH antibody titre, decreased LH and testosterone concentrations and decreased testicular volume, which reversed by the end of the study period. Therefore, these results suggest that immunizing against GnRH may be a possible choice for temporary and reversible immunocastration.

Gastrointestinal symptoms and psychological well-being in patients with microscopic colitis

Objective. Microscopic colitis (MC) and irritable bowel syndrome (IBS) are both gastrointestinal disorders with female predominance that affect well-being. Autoantibodies against gonadotropin-releasing hormone (GnRH) have recently been detected in IBS patients. The purpose of this study was to compare gastrointestinal symptoms and well-being in MC female outpatients, with or without coexisting IBS-like symptoms, and to examine the prevalence of GnRH antibodies in these patients. Material and methods. Women with biopsy-verified MC, at any outpatient clinic of the Departments of Gastroenterology, Skåne, between 2002 and 2010 were invited to participate in the study. The questionnaires Gastrointestinal Symptom Rating Scale (GSRS), Psychological General Well-being Index (PGWB), Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS), and Rome III were answered and blood samples collected. Autoantibodies (IgG, IgA, and IgM) against GnRH and GnRH-R (extracellular peptide of receptor) were determined by an enzyme-linked immunosorbent assay. Results. Altogether, 158 (66%) of 240 invited patients with MC were recruited to the study. Of these, 133 (55%) patients also accepted to provide blood samples. Patients with IBS-like symptoms (55%) experienced more symptoms and worse psychological well-being in all dimensions in GSRS and PGWB, and in all symptoms but constipation in VAS-IBS compared to patients without IBS symptoms. Only a minority of patients expressed antibodies against GnRH or GnRH-R, which did not differ between groups. Conclusions. MC patients fulfilling criteria for IBS experience more gastrointestinal symptoms and worse psychological well-being than those who do not. Autoantibodies against GnRH or GnRH-R are not frequently observed in MC patients.

EFFECTS OF A GONADOTROPIN-RELEASING HORMONE VACCINE ON OVARIAN CYCLICITY AND UTERINE MORPHOLOGY OF AN ASIAN ELEPHANT (ELEPHAS MAXIMUS)

This report describes the successful use of a gonadotropin-releasing hormone (GnRH) vaccine to suppress ovarian steroidogenic activity and to treat hemorrhage and anemia associated with reproductive tract pathology in a 59-year-old Asian elephant (Elephas maximus). The Repro-BLOC GnRH vaccine was administered subcutaneously as a series of 4 boosters of increasing dose from 3 to 30 mg of recombinant ovalbumin-GnRH fusion protein given at variable intervals after initial vaccination with 3 mg protein. Efficacy was confirmed over a year after initial vaccination based on complete ovarian cycle suppression determined by serum progestagen analyses. Estrous cycle suppression was associated with a significant increase in GnRH antibody binding and subsequent decrease in serum luteinizing hormone and follicle-stimulating hormone concentrations. Ultrasonographic examinations of the reproductive tract documented a reduction in uterine size and vascularity after immunization. The hematocrit level normalized soon after the initial intrauterine hemorrhage, and no recurrence of anemia has been detected. No substantive adverse effects were associated with GnRH vaccination. The results indicate that GnRH vaccination in elephants shows potential for contraception and management of uterine pathology in older elephants.

Effects of Gonadotropin-Releasing Hormone Immunization on Reproductive Function and Behavior in Captive Female Rocky Mountain Elk (Cervus elaphus nelsoni)1

Fertility control is a potential method for managing overabundant wildlife populations; however, current technology is limited by duration of treatment efficacy and unacceptable side effects. The objective of this study was to determine the efficacy of a single immunization with gonadotropin-releasing hormone (GnRH) vaccine to suppress reproductive function in pregnant female elk and to evaluate potential behavioral and pathological side effects of treatment. Eighteen captive adult female elk were randomly allocated to one of two experimental groups. Ten females were administered a conjugated and adjuvanted GnRH vaccine intramuscularly, and eight elk received an adjuvant sham vaccine without conjugated GnRH. We compared success of existing pregnancy, neonatal survival, subsequent fertility, reproductive behavior rates, and side effects of treatment between January 2006 and January 2010. The GnRH vaccination did not affect existing pregnancy or calf survival during the year that it was applied; however, it reduced the proportion of pregnant females for 3 yr. Male precopulatory behavior rates exhibited toward GnRH-vaccinated females tended to be greater than those directed at sham-vaccinated females during the second half of the breeding season, when GnRH vaccinates continued to be proceptive. Strong immune and inflammatory responses, including robust GnRH antibody concentrations in GnRH vaccinates, and sterile pyogranulomatous injection site abscesses in both groups, were consistent with vaccination. In conclusion, this GnRH vaccine resulted in prolonged, albeit reversible, impairment of fertility, and is associated with extended reproductive behaviors and partial suppression of hypothalamic-pituitary-gonadal axis function in captive female elk.

Patients with irritable bowel syndrome and dysmotility express antibodies against gonadotropin-releasing hormone in serum

The etiology of irritable bowel syndrome (IBS) and dysmotility is in most cases unknown. Organic, pathognomonic changes have not been described. We have previously demonstrated sporadic expressions of antibodies against gonadotropin-releasing hormone (GnRH) in serum from these patients. The aim of this study was to screen for the presence of GnRH antibodies in healthy subjects and patients with gastrointestinal (GI) diseases. Consecutive patients suffering from either IBS, idiopathic dysmotility, GI complaints secondary to diabetes mellitus, celiac disease or inflammatory bowel disease (IBD) were included. Healthy blood donors served as controls. Blood samples were taken for analyzing IgM and IgG antibodies against GnRH using an ELISA method. Medical records were scrutinized with respect to duration of symptoms, co-existing diseases, drug treatments, hereditary factors, and laboratory analyses. Healthy controls expressed low levels of GnRH IgM antibodies in a prevalence of 23%. The prevalence of GnRH IgM antibodies in IBS and dysmotility patients was 42% (P = 0.008), and the levels were higher (P = 0.000). Patients with diabetes mellitus expressed GnRH IgM antibodies in the same prevalence as controls (25%), but in higher levels (P = 0.02). Patients with celiac disease or IBD had the same or lower levels of antibodies. There were no associations between antibodies, other co-existing diseases or laboratory analyses. Higher levels of GnRH IgM antibodies were detected in patients with IBS and dysmotility, but not organic GI diseases, compared with healthy controls. These findings suggest that IBS and dysmotility to some extent may be of an autoimmune origin.

Oxytocin/vasopressin and gonadotropin‐releasing hormone from cephalopods to vertebrates

Recent advances in peptide search methods have revealed two peptide systems that have been conserved through metazoan evolution. Members of the oxytocin/vasopressin-superfamily have been identified from protostomian and deuterostomian animals, indicating that the oxytocin/vasopressin hormonal system represents one of the most ancient systems. In most protostomian animals, a single member of the superfamily shares oxytocin-like and vasopressin-like actions. Co-occurrence of two members has been discovered in modern cephalopods, octopus, and cuttlefish. We propose that cephalopods have developed two peptides in the molluscan evolutionary lineage like vertebrates have established two lineages in the oxytocin/vasopressin superfamily. The existence of gonadotropin-releasing hormone (GnRH) in protostomian animals was initially suggested by immunohistochemical analysis using chordate GnRH antibodies. A peptide with structural features similar to those of chordate GnRHs was originally isolated from octopus, and an identical peptide has been characterized from squid and cuttlefish. Novel forms of GnRH-like molecules from other molluscs, an annelid, arthropods, and nematodes demonstrate somewhat conserved structures at the N-terminal regions; but structures of the C-terminal regions critical to gonadotropin-releasing activity are diverse. These findings may be important for the study of the molecular evolution of GnRH in protostomian animals.