Synthetic Luteinizing Hormone-releasing Hormone Research Articles

Estrogen Receptors Alpha and Beta in POA-AHA Region Regulate Asymmetrically Ovulation.

We examined the role of the estrogen receptors alpha (ERα) and beta (ERβ) in of the preoptic-anterior hypothalamic area (POA-AHA) in the regulation of ovulation in rats. The number of ERα- and ERβ-immunoreactive (-ir) cells was determined at 09:00, 13:00, and 17:00h of each stage of the estrous cycle in intact rats. Additionally, the effects of blocking ERα and ERβ on ovulation rate at 09:00h on diestrus-2 or proestrus day through the microinjection of methyl-piperidino-pyrazole (MPP) or cyclofenil in either side of POA-AHA were evaluated. The number of ERα-ir and ERβ-ir cells in POA-AHA varied in each phase of estrous cycle. Either MPP or cyclofenil in the right side of POA-AHA on diestrus-2day reduced the ovulation rate, while at proestrus day it was decreased in rats treated in either side with MPP, and in those treated with cyclofenil in the left side. MPP or cyclofenil produced a decrease in the surge of luteinizing hormone levels (LH) and an increase in progesterone and follicle stimulating hormone (FSH). Replacement with synthetic luteinizing hormone-releasing hormone in non-ovulating rats treated with MPP or cyclofenil restored ovulation. These results suggest that activation of estrogen receptors on the morning of diestrus-2 and proestrus day asymmetrically regulates ovulation and appropriately regulates the secretion of FSH and progesterone in the morning and afternoon of proestrus day. This ensures that both, the preovulatory secretion of LH and ovulation, occur at the right time.

Strategy to enhance lung cancer treatment by five essential elements: inhalation delivery, nanotechnology, tumor-receptor targeting, chemo- and gene therapy.

Non-Small Cell Lung Carcinoma (NSCLC), is the most common type of lung cancer (more than 80% of all cases). Small molecule Tyrosine Kinase (TK) Inhibitors acting on the Epidermal Growth Factor Receptors (EGFRs) are standard therapies for patients with NSCLC harboring EGFR-TK inhibitor-sensitizing mutations. However, fewer than 10 % of patients with NSCLC benefit from this therapy. Moreover, even the latest generation of EGFR inhibitors can cause severe systemic toxicities and are ineffective in preventing non-canonical EGFR signaling. In order to minimize and even overcome these limitations, we are proposing a novel multi-tier biotechnology treatment approach that includes: (1) suppression of all four types of EGFR-TKs by a pool of small interfering RNAs (siRNAs); (2) induction of cell death by an anticancer drug, (3) enhancing the efficiency of the treatment by the local inhalation delivery of therapeutic agents directly to the lungs (passive targeting), (4) active receptor-mediated targeting of the therapy specifically to cancer cells that in turn should minimize adverse side effects of treatment and (5) increasing the stability, solubility, and cellular penetration of siRNA and drug by using tumor targeted Nanostructured Lipid Carriers (NLC).Methods: NLCs targeted to NSCLC cells by a synthetic Luteinizing Hormone-Releasing Hormone (LHRH) decapeptide was used for the simultaneous delivery of paclitaxel (TAX) and a pool of siRNAs targeted to the four major forms of EGFR-TKs. LHRH-NLC-siRNAs-TAX nanoparticles were synthesized, characterized and tested in vitro using human lung cancer cells with different sensitivities to gefitinib (inhibitor of EGFR) and in vivo on an orthotopic NSCLC mouse model.Results: Proposed nanoparticle-based complex containing an anticancer drug, inhibitors of different types of EGFR-TKs and peptide targeted to the tumor-specific receptors (LHRH-NLC-siRNAs-TAX) demonstrated a favorable organ distribution and superior anticancer effect when compared with treatment by a single drug, inhibitor of one EGFR-TK and non-targeted therapy.Conclusions: The use of a multifunctional NLC-based delivery system substantially enhanced the efficiency of therapy for NSCLC and possibly will limit adverse side effects of the treatments. The results obtained have the potential to significantly impact the field of drug delivery and to improve the efficiency of therapy of lung and other types of cancer.

Targeted gold nanoparticles enhance sensitization of prostate tumors to megavoltage radiation therapy in vivo

We report potent radiosensitization of prostate cancers in vitro and in vivo using goserelin-conjugated gold nanorods. Progressive receptor-mediated internalization of conjugated nanorods over time increases the radiation interaction cross-section of cells and contributes to the effects observed in vitro. The low concentrations of gold required, the long interval between injection of nanoparticles and radiation, and the use of megavoltage radiation to generate radiosensitization in vivo foretell the possibility of eventual clinical translation of this approach. From the Clinical EditorThe ability of gold nanoparticles (AuNPs) to enhance the effect of physical radiation dose on tumor cells is known. This radiosensitization effect is thought to result from an increased number of photoelectric absorption events and the increased number of electrons present in gold. The authors here sought to further increase the amount and specificity of gold accumulation in prostatic cancer cells by conjugating gold nanorods to goserelin, a synthetic luteinizing hormone releasing hormone (LHRH) analogue that would bind to the LHRH receptor overexpressed in prostate cancers. It was shown that tumour cells were more sensitive to megavoltage radiation therapy. It is hoped that there would be eventual clinical translation of this approach.

Ovulation requires the activation on proestrus of M₁ muscarinic receptors in the left ovary.

We analyzed the effects of chemically blocking type 1 muscarinic receptors (M1R) on either the left or right ovary on ovulation rate, number of ova shed and steroid hormones levels. M1R were unilaterally blocked in ovary with the M1R selective antagonist pirenzepine (PZP). PZP was delivered into the bursa ovarica of the left or right ovary of adult rats at 13:00 h on proestrus day. PZP treatment in the left but not in the right ovary blocked ovulation. PZP did not modify the number of ova shed, nor progesterone or 17β-estradiol serum levels. The surge of luteinizing hormone levels was diminished while that of follicle-stimulating hormone did not change in animals treated with PZP in the left ovary. Interestingly, treatment with either synthetic luteinizing hormone-releasing hormone or human chorionic gonadotropin 1 h after PZP administration in the left ovary restored ovulation in both ovaries. The presence of M1R protein in the theca cells of the ovarian follicles as well as in cells of the corpus luteum was detected on proestrus day. These results suggest that M1R activation in the left ovary is required for pre-ovulatory gonadotropin-releasing hormone (GnRH) secretion and ovulation. Furthermore, these results also suggest that M1R in the left ovary might be regulating ovulation asymmetrically through a stimulatory neural signal relayed to the hypothalamus via the vagus nerve to induce the GnRH secretion which then triggers ovulation.

Triple negative breast cancers express receptors for LHRH and are potential therapeutic targets for cytotoxic LHRH-analogs, AEZS 108 and AEZS 125.

BackgroundTriple negative breast cancer (TNBC) is a distinct subtype of breast cancer burdened with a dismal prognosis due to the lack of effective therapeutic agents. Receptors for LHRH (luteinizing hormone-releasing hormone) can be successfully targeted with AEZS-108 [AN-152], an analog of LHRH conjugated to doxorubicin. Our study evaluates the presence of this target LHRH receptor in human specimens of TNBC and investigates the efficacy and toxicity of AEZS-108 in vivo. We also studied in vitro activity of AEZS-125, a new LHRH analog conjugated with the highly potent natural compound, Disorazol Z.Methods69 human surgical specimens of TNBC were investigated for LHRH-R expression by immunohistochemistry. Expression of LHRH-R in two TNBC cell lines was evaluated by real time RT-PCR. Cytotoxicity of AEZS-125 was evaluated by Cell Titer Blue cytoxicity assay. LHRH- receptor expression was silenced with an siRNA in both cell lines. For the in vivo experiments an athymic nude mice model xenotransplanted with the cell lines, MDA-MB-231 and HCC 1806, was used. The animals were randomised to three groups receiving solvent only (d 1, 7, 14, i.v.) for control, AEZS-108 (d 1, 7, 14, i.v.) or doxorubicin at an equimolar dose (d 1, 7, 14, i.v.).ResultsIn human clinical specimens of TNBC, expression of the LHRH-receptor was present in 49% (n = 69).HCC 1806 and MDA-MB-231 TNBC cells expressed mRNA for the LHRH-receptor. Silencing of the LHRH-receptor significantly decreased the cytotoxic effect of AEZS-108. MDA-MB-231 and HCC 1806 tumors xenografted into nude mice were significantly inhibited by treatment with AEZS-108; doxorubicin at equimolar doses was ineffective.As compared to AEZS 108, the Disorazol Z – LHRH conjugate, AEZS-125, demonstrated an increased cytotoxicity in vitro in HCC 1806 and MDA-MB-231 TNBC; this was diminished by receptor blockade with synthetic LHRH agonist (triptorelin) pretreatment.ConclusionThe current study confirms that LHRH-receptors are expressed by a significant proportion of TNBC and can be successfully used as homing sites for cytotoxic analogs of LHRH, such as AEZS-108 and AEZS-125.

A novel synthetic luteinizing hormone-releasing hormone (LHRH) analogue coupled with modified β-cyclodextrin: Insight into its intramolecular interactions

BackgroundCyclodextrins (CDs) in combination with therapeutic proteins and other bioactive compounds have been proposed as candidates that show enhanced chemical and enzymatic stability, better absorption, slower plasma clearance and improved dose–response curves or immunogenicity. As a result, an important number of therapeutic complexes between cyclodextrins and bioactive compounds capable to control several diseases have been developed. ResultsIn this article, the synthesis and the structural study of a conjugate between a luteinizing hormone-releasing hormone (LHRH) analogue, related to the treatment of hormone dependent cancer and fertility, and modified β-cyclodextrin residue are presented. The results show that both the phenyl group of tyrosine (Tyr) as well as the indole group of tryptophan (Trp) can be encapsulated inside the cyclodextrin cavity. Solution NMR experiments provide evidence that these interactions take place intramolecularly and not intermolecularly. ConclusionsThe study of a LHRH analogue conjugated with modified β-cyclodextrin via high field NMR and MD experiments revealed the existence of intramolecular interactions that could lead to an improved drug delivery. General significanceNMR in combination with MD simulation is of great value for a successful rational design of peptide–cyclodextrin conjugates showing stability against enzymatic proteolysis and a better pharmacological profile.

Hormonal induction of spermiation, courting behavior and spawning in the southern bell frog, Litoria raniformis

We trialled the efficacy of various exogenous hormones to induce spermiation, courtship behavior, and spawning in the "endangered" southern bell frog, Litoria raniformis. Intralymphatic administration of Lucrin(®), a synthetic nonapeptide luteinizing hormone releasing hormone (LHRH), was used successfully to induce courting behaviors and ejaculation of spermatozoa in males. Various hormones, including Lucrin(®), another synthetic LHRH analog ([des-Gly(10), D-Ala(6)]-LHRH), human chorionic gonadotropin, progesterone, and a dopamine receptor antagonist failed to promote oviposition and spawning in females. This and earlier studies indicate that in the efficacy of hormonal induction in amphibians varies between taxa, hormones, and genders. The lack of response in females may limit the use of reproduction technology in the southern bell frog and closely related species of Australian bell frogs.

Introducing Vantas: The First Once-Yearly Luteinising Hormone-Releasing Hormone Agonist

For more than 30 years, androgen-deprivation therapy (ADT) has been a standard treatment for advanced prostate cancer (PCa). This modality of treatment frequently utilises synthetic luteinising hormone-releasing hormone (LHRH) agonists such as leuprolide, goserelin, triptorelin, and buserelin, which are available as 1-, 2-, 3-, or 6-mo intramuscular or subcutaneous depot injections. A deep subcutaneous LHRH antagonist, degarelix, is also available but only as a 1-mo formulation. Despite their long track record of use, many current depot formulations of LHRH agonists have several disadvantages, including repeated administration, variable depot biodegradability, difficulty in removal, and variable duration of activity. The development and formulation of the most potent synthetic LHRH agonist, histrelin acetate, as a once-yearly subcutaneous implant (Vantas) that can be quickly and simply inserted superficially into the upper arm has provided several advantages over other currently available LHRH agonists. Histrelin acetate has been shown to quickly and effectively suppress serum testosterone levels to well below castrate level within 4 wk of treatment. This reduction in serum testosterone is paralleled with reductions in prostate-specific antigen and luteinising hormone. Importantly, when the histrelin implant is removed and a fresh implant is inserted, the efficacy has been shown to be extended up to 4.5 yr (with multiple reinsertions). In addition, the testosterone “surge” that is associated with the repeat administration of other currently available depot LHRH agonist formulations has been shown to be absent with the histrelin implant. A further benefit of the histrelin implant is the ease of removal and the rapidity with which the hypothalamic–pituitary–testicular axis may potentially normalise. Taken collectively, the properties of the histrelin implant offer potent and consistent suppression of serum testosterone with the benefit of easy and flexible administration.

Temperature and salmonid reproduction: implications for aquaculture

Fish reproduction is likely to be affected by increasing water temperatures arising from climate change. Normal changes in environmental temperature have the capacity to affect endocrine function and either advance or retard gametogenesis and maturation, but above-normal temperatures have deleterious effects on reproductive processes. In Atlantic salmon Salmo salar, exposure to elevated temperature during gametogenesis impairs both gonadal steroid synthesis and hepatic vitellogenin production, alters hepatic oestrogen receptor dynamics and ultimately results in reduced maternal investment and gamete viability. Exposure to high temperature during the maturational phase impairs gonadal steroidogenesis, delaying or inhibiting the preovulatory shift from androgen to maturation-inducing steroid production. There are also deleterious effects on reproductive development of female broodstock of rainbow trout Oncorhynchus mykiss and Arctic charr Salvelinus alpinus when they are exposed to elevated temperature. Less is known about temperature effects on male fishes but inhibition of spermiation has been observed in S. salar and O. mykiss. Among wild stocks, the response to elevated temperature will involve behavioural thermoregulation with consequent change in geographical ranges and the possibility of local extinctions in some regions. For domesticated stocks, containment in the culture environment precludes behavioural thermoregulation and aquaculturists will be required to develop adaptive strategies in order to maintain productivity. The most direct strategy is to manage the thermal environment using one or more of a range of developing aquaculture technologies. Alternatively, there is potential to mitigate the effects of elevated temperature on reproductive processes through endocrine therapies designed to augment or restore natural endocrine function. Studies largely on S. salar have demonstrated the capacity for synthetic luteinizing hormone-releasing hormone to offset the inhibitory effects of elevated temperature on maturational events in both sexes, but the potential for hormone therapy to provide protection during gametogenesis is still largely unexplored.

Evaluation of Effects of Synthetic Luteinizing Hormone-Releasing Hormone (L.H.-R.H.) Loading in Male Sterility

Summary The effects of L.H.-R.H. loading (0.1 mg, intramusculary) on plasma levels of F.S.H., L.H., and testosterone were evaluated by applying radioimmunoassay on 15 male sterility patients and 5 normal males. The results showed that the response of testosterone to L.H.-R.H. loading was insignificant compared to the generally sharp response of both F.S.H. and L.H., implying that in all likelihood problems in the testicles rather than the pituitary are responsible for male sterility. The data presented in this report emphasize that in endocrinological examinations, use of the L.H.-R.H. test is evidently more helpful than relying on the conventional H.C.G. test, or the recently popularized rapid H.C.G. test, particularly in view of its availability for simultaneous and efficient evaluation of both pituitary and gonadal functions. Zusammenfassung Bei 5 gesunden Mannern und 15 andrologischen Patienten (Oligozoo- und Azoosper-mie) wurden die Plasmawerte fur FSH, LH und Testosteron mittels Radioimmunassay nach Belastung mit LH-RH (0,1 mg i.m.) untersucht. In den Ergebnissen kann gezeigt werden, das die Antwort von Testosteron auf die LH-RH-Belastung zu keinen signifi-kanten Resultaten fuhrt verglichen mit der allgemein schnellen Reaktion bei FSH und LH, wobei in die Uberlegungen einbezogen wird, das Probleme an den Hod en aller Wahrscheinlichkeit nach sehr viel eher als solche im Bereich der Hypophyse fur die Sterilitat des Mannes verantwortlich sind. Die vorgelegten Ergebnisse zeigen, das bei endokrinologischen Untersuchungen der LH-RH-Test evident nutzlicher ist als der konventionelle HCG-Test oder der kurzlich popular gewordene schnelle HCG-Test; das gilt vor allem im Hinblick auf seine Anwend-barkeit fur simultane und wirksame Auswertung der hypophysaren und gonadalen Funktionen. Fur LH und FSH ergibt sich 20 Min. nach Gabe von 0,1 mg LH-RH das Maximum fur Normalpersonen und Oligozoospermiepatienten, wahrend Azoospermiepatienten das FSH-Maximum erst nach 60 Min. aufweisen. Die Testosteronplasmawerte verhalten sich demgegenuber uneinheitlich. Resumen En un intento de arrojar alguna luz sobre las causas de esterilidad masculina, los autores efectuaron tests de sobrecarga de LH-RH en 15 varones esteriles y 5 normales, evaluando los cambios en los niveles plasmaticos de gonadotrofinas y testosterona. Diez de los pacientes esteriles presentaban oligoastenozoospermia severa (menos de 12 millones). Cuatro azoospermia y uno astenozoospermia. Se determino por RIA los niveles basales y a los 10, 20, 30, 60 y 90 minutos de la administration intramuscular de 0,1 mg de LH-RH sintetica. En los varones normales se objetivo a los 60 minutos un pico de FSH (2'4 veces mas alto que el valor basal). El pico de LH aparecio a los 30 minutos con un incremento de 5'8 veces sobre el nivel basal. El pico de testosterona (1'7 veces mas alto que el nivel normal) se alcanzo a los 60 minutos. En todos los pacientes esteriles aumento la FSH y LH y testosterona con la administracion de LH-RH, si bien los aumentos fueron para la FSH y para la LH y testosterona mayores que en los normales. El test de LH-RH tiene dos ventajas sobre el test de HCG: requiere horas y no dias como este ultimo y se puede estudiar simultaneamente la funcion secretora adenohipo-fisaria y de las celulas de Leydig. En este trabajo se muestra que los cambios en los niveles de FSH, LH y testosterona, como respuesta a la administracion, fueron marcadamente diferentes en los pacientes oligozoospermicos y en los azoospermicos. Asimismo, en los varones normales, la testosterona aumento menos y mas tarde que la LH, pero en los pacientes esteriles no se observo relacion especifica entre los niveles de las dos hormonas, LH y testosterona.

Cryopreservation of Sperm from Endangered Pallid Sturgeon

AbstractWe sought to develop sperm cryopreservation methods for the pallid sturgeon Scaphirhynchus albus, a federally listed endangered species. Males were injected with synthetic luteinizing hormone releasing hormone at 50 μg/kg of body weight. After 24 h, sperm were collected, diluted at a ratio of 1:4 (sperm : extender) with Hanks' balanced salt solution (HBSS; diluted to 100 milliosmoles/kg), and kept refrigerated until use. Methanol was used as a cryoprotectant at concentrations of 5, 10, and 15% (volume per volume) and was mixed 1:1 with HBSS before the experiment to reduce effects of initial mixing. Sperm were mixed with the cryoprotectant, loaded into 0.5‐mL straws, packed into goblets (5 straws/goblet), and placed in the lower position on aluminum canes. Motility was estimated before freezing to determine the effects of cryoprotectant toxicity; there was no significant difference in motility at the concentrations tested (P = 0.4828). After a 2‐min equilibration period, the canes were lowered into a nitrogen vapor shipping dewar. The cooling rate of −22°C/min was recorded by thermocouples inserted into 0.5‐mL straws filled with extender and cryoprotectant. After 1 year of storage in liquid nitrogen, straws were thawed in a 40°C water bath for 9 s and motility was estimated. Postthaw motility did not differ among the cryoprotectants tested (P = 0.4880). Each sample was used to fertilize approximately 150 eggs, which were incubated at 21°C. Sperm that was cryopreserved with 5% or 10% methanol produced eggs with significantly higher hatch rates did sperm cryopreserved with 15% methanol (P < 0.0001). The development of techniques for cryopreserved sperm of pallid sturgeon allows for the creation of germplasm repositories that will aid in the recovery of this endangered species.

Leuprorelin depot injection: patient considerations in the management of prostatic cancer.

Hormone therapy is well established for treating patients with prostate cancer and remains the mainstay of the treatment of metastatic and locally advanced disease, this article reviews the rationale for its use, its different forms, and complications and controversies still surrounding some of its modalities. Availability of long-acting synthetic luteinizing hormone-releasing hormone (LHRH) agonists revolutionized the hormonal treatment of prostate cancer, and helped to avoid the emotional and psychological effects related to surgical castration. The depot formula has gained wide acceptance from both patients and physicians. This review emphasizes the newer, long-acting formula, leuprorelin (leuprolide acetate), especially the 6-month formula, its advantage over over shorter-acting depot products, and its potential to become a standard of care for patients eligible for androgen deprivation therapy.

Novel Polymeric Prodrug with Multivalent Components for Cancer Therapy

We designed, synthesized, and evaluated in vitro and in vivo a novel targeted anticancer polymeric prodrug containing multiple copies of tumor targeting moiety [synthetic luteinizing hormone-releasing hormone (LHRH) peptide, analog of LHRH] and anticancer drug (camptothecin). One, two, or three molecules of the targeting peptide and anticancer drug were covalently conjugated with bis(2-carboxyethyl) polyethylene glycol polymer using citric acid as a multivalent spacer. We showed that LHRH peptide was bound to extracellular receptors and localized in plasma membrane of cancer cells. The designed tumor-targeted prodrug increased the solubility of anticancer drug and offered cytoplasmic and/or nuclear delivery of drug to cancer cells expressing LHRH receptors. The multicomponent prodrug containing three copies of the targeting peptide and drug was almost 100 times more cytotoxic and substantially had enhanced antitumor activity compared with the analogous nontargeted prodrug and prodrugs containing one or two copies of active components.

Granulomas induced by subcutaneous injection of leuprorelin acetate

Leuprorelin acetate, a chemotherapeutic agent used to treat prostate cancer, is a synthetic luteinizing hormone-releasing hormone (LHRH) agonist. We report a 75-year-old man who presented with several large subcutaneous nodules at the site of leuprorelin acetate injections for his prostatic cancer. A biopsy of the nodules disclosed epithelioid granulomatous inflammation and resulted in a diagnosis of drug-induced granulomatous reaction to leuprorelin acetate.

Eligard ®: Pharmacokinetics, Effect on Testosterone and PSA Levels and Tolerability

Luteinising hormone releasing hormone (LHRH) agonists (e.g. leuprolide) have been the mainstay of advanced and metastatic prostate cancer treatment. LHRH agonist treatment has also become part of the treatment of early prostate cancer as neoadjuvant and adjuvant treatment to radical therapy. Early therapies consisted of daily injections of synthetic LHRH analogues (e.g. leuprolide, goserelin), but recent years have seen the development of depot formulations with 1, 3 or 4-monthly injections. These depot formulations have contributed considerably to the current widespread use of LHRH agonists, and have improved the patients’ adherence to treatment. Unfortunately, with these formulations the achievement of optimal control of testosterone defined as appropriate castration levels and low levels of breakthroughs, as well as acute-on-chronic responses, is currently overestimated. In order to achieve the optimal control of testosterone, a new depot formulation of leuprolide, Eligard ®, has been developed, which contains a novel delivery system (Atrigel ®) with potential advantages over the older systems. Eligard ® allows for a favourable pharmacokinetic profile, delivering a twofold higher quantity of LHRH agonist than seen with other available depot preparations in the European Union (EU), in a consistent and stable manner. As a result, testosterone levels are better suppressed and, unlike other delivery systems, Eligard ® achieves levels of testosterone as seen with orchiectomy and has, to date, shown no escape responses. In addition, clinical trials have shown that Eligard ® produces mild episodes of hot flushes. Eligard ® has a small volume which is administered subcutaneously with a very short needle, reducing injection site discomfort. Main adverse events associated with subcutaneous injection are mild and of short duration, comprising irritation, skin discolouration and erythema. It is concluded that Eligard ®, consisting of a novel delivery system with an improved pharmacokinetic profile compared with other existing depot formulations, leads to reliable and sustained testosterone suppression with a favourable side effect profile.

Synthetic luteinizing hormone releasing hormone (LHRH) vaccine for effective androgen deprivation and its application to prostate cancer immunotherapy

We have designed a peptide-based immunotherapeutic vaccine for treatment of androgen-responsive prostate cancer. The vaccine targets the luteinizing hormone-releasing hormone (LHRH) decapeptide that results in an androgen-deprivation immunotherapy. The design elements of the peptide immunogens are the LHRH peptide or B cell epitope synthetically linked to different promiscuous helper T cell (Th) sequences, the UBITh ® epitopes, derived from four natural pathogens for effective immunogenicity in outbred populations, and in some cases, also linked to an adjuvanting peptide from Yersinia invasin (Inv) protein. The UBITh ® LHRH immunogens are adsorbed on Alhydrogel or formulated as several different oil-based emulsions and tested in rodents, dogs, and a non-human primate, baboons. The immunogens generate an anti-LHRH antibody response specific to the LHRH decapeptide element in contrast to LHRH conjugate-carrier protein vaccines where only a small portion of the antibody response is directed to the target epitope and epitopic suppression is noted. Individual UBITh ® peptide domains, but not the LHRH and Inv peptide domains, are stimulatory in lymphocyte cultures. The UBITh ® LHRH immunogens in a clinically applicable formulation, controlled the growth of Dunning R3327-H androgen-responsive prostate tumor cells in rats. The results demonstrate universal responsiveness and long duration of androgen deprivation from three diverse species, and thus vaccine efficacy.

Ultrastructural changes in granulosa cells and plasma steroid levels after administration of luteinizing hormone-releasing hormone in the Western painted turtle, Chrysemys picta

In this study we investigated the effects of treatment by luteinizing hormone-releasing hormone (LHRH) on the morphology and steroid release of ovarian tissues in the Western painted turtle, (Chrysemys picta). In Experiment I, four adult female turtles were injected with synthetic mammalian LHRH (i.p., 500pg/g bodyweight) and four with saline 2–3 weeks prior to ovulation. Granulosa cells from LHRH-treated turtles vs controls contained both preovulatory follicles (16–20mm in diameter) and small follicles (0.5–1.00mm in diameter) with increased RER, free ribosomes and mitochondria with swollen cristae. An increase in the amount of cytoskeletal material (microfilaments) was observed in granulosa cells of the experimental turtles compared to the controls. Cytoplasmic extensions of the oocyte and granulosa cells were longer in the small follicles of treated animals, accounting for the observed increase in the thickness of the zona pellucida (ZP) over the controls. In Experiment II, administration of LHRH (i.p.) to 10 turtles during the same period triggered a substantial increase in plasma progesterone and estradiol-17β levels over the 10 saline-injected controls. This supports the idea that in this species, as in mammals, steroidogenic activity in the ovarian follicles are under the control of the hypothalamic–pituitary axis. The ultrastructure and hormonal levels of the experimental animals were typical of untreated turtles just prior to ovulation. In this species the development of follicles and steroidogenesis can be stimulated prematurely by a releasing hormone from a nonreptilian origin.

Use of Synthetic Human Luteinizing Hormone Releasing Hormone for Induction of Breeding in the Cricket Frog, Acris crepitans

ABSTRACT In order to study the effects of environmental contaminants on the sexual development of the cricket frog, Acris crepitans, a system of laboratory breeding of this species was devised using induction of mating by subcutaneous injection of synthetic human luteinizing hormone releasing hormone at doses ranging from 169–676 mg/kg body weight. Viable tadpoles were obtained from frogs that had been maintained in captivity for approximately 1.5 years and from recently captured individuals. The techniques and doses described represent a starting point for further studies aimed at optimizing captive breeding technique for this species

Antigenic and immunogenic properties of totally synthetic peptide-based anti-fertility vaccines.

In this study we describe the results of experiments in which a variety of totally synthetic luteinizing hormone releasing hormone (LHRH) vaccines were assembled and examined for their abilities to elicit antibody responses and induce sterility in mice. It is shown that totally synthetic vaccines consisting of a 15 residue-defined T cell epitope and the 10 residue LHRH epitope not only induced high titers of antibody but also induced sterility. This effect did not appear to correlate with antibody titer, antibody isotype or comparative antibody affinity, but may be related to the length of time for which antibodies are present to exert their influence.

Effect of treatment with LHRH analogue on oocyte maturation, plasma sex steroid levels and egg production in female striped trumpeter Latris lineata (Latrididae)

Striped trumpeter Latris lineata (Schneider, 1801) are currently being investigated for their aquaculture potential. Little is known of the reproductive physiology of this fish and a limited supply of eggs is hindering larval rearing trials. This study assessed the effect of hormone therapy to induce ovulation in wild caught broodstock. Female striped trumpeter were implanted with 0, 100 or 200 μg kg −1 body weight of a synthetic luteinizing hormone releasing hormone analogue (LHRHa: des-Gly 10, [ d-Ala 6]-LH-RH ethylamide), administered in a slow release cholesterol pellet ( n=12 per treatment). Blood and ovarian samples were collected daily from each fish, and the volume of eggs produced was recorded. Plasma levels of testosterone (T), 17β-oestradiol (E 2) and 17α20β-dihydroxy-4-pregnen-3-one (17,20βP) were measured by radioimmunoassay. Four, 11 and 12 fish treated with 0, 100 or 200 μg kg −1 LHRHa respectively, ovulated. When compared to the control group, both LHRHa treatments resulted in significantly increased ( P<0.05) egg volumes overall and also on Day 4 post-implant in terms of daily volumes. Whilst there was no significant difference ( P>0.05) in egg volumes between the two LHRHa treatments, when combined, two groups could be defined; those fish that underwent only `one or two ovulations' (OTO) and those that underwent `three or more ovulations' (TMO). The OTO fish ( n=11) had similar plasma steroid levels to the control fish whereas the TMO fish ( n=12) had significantly increased ( P<0.05) plasma levels of T, E 2 and 17,20βP, with peaks occurring on Day 1 for T (4.8 ng ml −1) and on Day 2 for E 2 and 17,20βP (2.2 and 1.3 ng ml −1, respectively). Twenty-one of the 24 LHRHa-treated fish first ovulated on Day 4 and, in the TMO fish, subsequent clutches of eggs were produced approximately every 3 days for up to 5 cycles. Oocyte recruitment appeared to originate from pre-vitellogenic oocytes from the third clutch onward. This work identified female striped trumpeter as multiple spawners with group synchronous oocyte development and showed LHRHa to be an effective stimulant for the induction and synchronization of ovulation.