Use of a GnRH synthetic analog (buserelin) for estrous induction in female dogs / Utilização de análogo sintético de GnRH (buserelina) na indução do estro em cadelas

The aim of this study was to evaluate the effectiveness of a GnRH synthetic analog, as an estrous inducer in female dogs when administered during the anestrous phase, and to evaluate the pregnancy rate achieved through natural copulation. For this purpose, ten female dogs of different breeds were used. The subjects received buserelin by intramuscular injections at a dose of 2,1mcg when female dogs weighed up to 10kg (Group 1) and of 4,2mcg when the dogs weighed above 10kg (Group 2). Of the ten subjects, only three presented estrus after a single injection of buserelin: two dogs from Group 1 and one dog from Group 2 on average 7±1.29 days. The remaining seven dogs were given a second dose of buserelin, equal to the first administration. Of these, three belonged to Group 1 and four to Group 2. Four of these dogs exhibited clinical signs of estrus within, on average 9±7.3 days from the second injection. The seven female dogs that did enter estrus were fertilized successfully through natural copulation. The administration of buserelin was effective in inducing estrus in female dogs during the anestrous phase, with a maximum of two administrations.(AU)

Objetivou-se avaliar a eficácia de um análogo sintético ao GnRH como indutor de estro em cadelas em anestro e a taxa de prenhez por meio de cópula natural. Para isso, foram utilizadas 10 fêmeas caninas de diferentes raças. Cadelas de até 10kg de peso (grupo 1) foram submetidas à administração de buserelina por via intramuscular, na dose de 2,1mcg, e cadelas acima de 10kg (grupo 2) foram submetidas à mesma medicação, porém na dose de 4,2mcg. Das fêmeas em anestro, apenas três apresentaram estro com apenas uma aplicação, sendo duas do grupo 1 e uma do grupo 2, em 7±1,29 dias, em média. Em sete cadelas foi administrada mais uma dose de buserelina; destas, quatro eram pertencentes ao grupo 2 e três eram do grupo 1. Os sinais de estro ocorreram, em média, após 9±2,73 dias da segunda aplicação. As sete cadelas que manifestaram estro foram fertilizadas por meio de cópula natural. A administração de buserelina é eficiente para a indução de estro, em cadelas em anestro, em, no máximo, duas aplicações.(AU)

Short-term buserelin administration induces apoptosis and morphological changes in adult rat testes

Abstract Purpose: To investigate the effect of buserelin on gonadal structure and function in adult male rats. Methods: Twenty-four adult Wistar male rats were divided into three groups: two treated groups and controls. The first and second treated groups received 300 (low dose) and 500 (high dose) µg/kg buserelin, respectively, and the control group received normal saline. All groups were treated subcutaneously for five days. Results: The seminiferous tubular epithelial thickness was significant decreased in the treated groups compared with those in the control. There was a significant increase in apoptotic cell death in high dose treated group compared with low dose treated and control groups. No significant difference in serum testosterone level was observed after one month in the three groups. Conclusion: Buserelin induces apoptotic cell death and decreased diameter and epithelium thickness of seminiferous tubules in the adult rat testes.

Ovulatory response of different GnRH analogues and subsequent corpus luteum lifespan in the presence of norgestomet in Holstein heifers

This study investigated the effect of GnRH analogues on inducing ovulation of dominant follicle [DF] and subsequent corpus luteum [CL] lifespan in the presence of norgestomet implant in Holstein heifers. On day 6 to 8 of the estrous cycle [day 0 of the experiment], all heifers [n=15] received norgestomet implant followed by prostaglandin injection on days 0 and 1. On day 4, group 1 [n=4] and 2 [n=4] heifers received 12.5 and 25 microg Alarelin, respectively. Heifers in group 3 [n=3] received 10 microg Buserelin. Heifers in control group [n=4] did not receive any further treatment. Norgestomet was removed on day 8 in the treatment group and kept throughout the experiment in control group. From day 0, blood sampling and ultrasonography were performed. Heifers were monitored after inducing ovulation for 2 consecutive estrous cycles. DF ovulated within 33 h after GnRH injection. Progesterone started to rise on day 3 and declined on day 7.45 +/- 0.28 after GnRH injection. Heifers in treatment groups displayed estrus 7.73 +/- 0.24 days after GnRH injection followed by spontaneous ovulation. The lifespan of CLs were 5.36 +/- 0.28 and 16.9 +/- 0.37 days after inducing ovulation of DF in the presence of norgestomet and following spontaneous ovulation, respectively [P<0.05]. In conclusion, the half dose of Alarelin induced ovulation of DF and the presence of single norgestomet implant after ovulation may be associated with short luteal lifespan

Participation of the endoplasmic reticulum protein chaperone thio-oxidoreductase in gonadotropin-releasing hormone receptor expression at the plasma membrane

Chaperone members of the protein disulfide isomerase family can catalyze the thiol-disulfide exchange reaction with pairs of cysteines. There are 14 protein disulfide isomerase family members, but the ability to catalyze a thiol disulfide exchange reaction has not been demonstrated for all of them. Human endoplasmic reticulum protein chaperone thio-oxidoreductase (ERp18) shows partial oxidative activity as a protein disulfide isomerase. The aim of the present study was to evaluate the participation of ERp18 in gonadotropin-releasing hormone receptor (GnRHR) expression at the plasma membrane. Cos-7 cells were cultured, plated, and transfected with 25 ng (unless indicated) wild-type human GnRHR (hGnRHR) or mutant GnRHR (Cys14Ala and Cys200Ala) and pcDNA3.1 without insert (empty vector) or ERp18 cDNA (75 ng/well), pre-loaded for 18 h with 1 µCi myo-[2-3H(N)]-inositol in 0.25 mL DMEM and treated for 2 h with buserelin. We observed a decrease in maximal inositol phosphate (IP) production in response to buserelin in the cells co-transfected with hGnRHR, and a decrease from 20 to 75 ng of ERp18 compared with cells co-transfected with hGnRHR and empty vector. The decrease in maximal IP was proportional to the amount of ERp18 DNA over the range examined. Mutants (Cys14Ala and Cys200Ala) that could not form the Cys14-Cys200 bridge essential for plasma membrane routing of the hGnRHR did not modify maximal IP production when they were co-transfected with ERp18. These results suggest that ERp18 has a reduction role on disulfide bonds in wild-type hGnRHR folding.

Pituitary gland activity following ultralong versus long down regulation

The aim of this prospective comparative study was to investigate the pituitary gland activity after prolonged down regulation with Goserelin and after milder down regulation of patients underwent IVF treatment under long down regulation protocol with daily injections of Buscrelin. The pituitary activity of 21 patients received Goserelin [Zoladex] for 3 months was investigated and the results were compared with the pituitary activity of 50 patients received daily Buserelin from day 21 of the cycle preceding the IVF treatment cycle [8-14 days]. The pituitary gland achieved a profound degree of down regulation 4 weeks post Goserelin injections and maintained the same degree of down regulation following each subsequent injection. The LH and E2 were more profoundly suppressed by the depot GnRH agonist [Zoladex] than the daily Buserelin administration. However the pituitary remains responsive to Buserelin by producing pulses of FSH and LH despite the down regulation in both groups. The amplitude of these pulses were similar although the LH levels were significantly higher in group 2. These pulses are probably the source of endogenous LH required for steroidogenesis. This explains the success of IVF after profound down regulation despite the use of Pure FSH for ovarian stimulation

Successful treatment of unilateral cryptorchid boys risking infertility with LH-RH analogue

INTRODUCTION: Infertility is the primary concern for boys with uni- or bilateral undescended testes. An early and seemingly successful orchiopexy does not improve fertility in a substantial number of cryptorchid males. We confirmed that LH-RH analogue (LH-RHa) treatment induces an increase in and maturation of the germ cells; however, it was uncertain if treatment would improve the chance of fertility later in life. MATERIALS AND METHODS: Thirty unilateral cryptorchid boys, with an average age of 3 years at the time of surgery, were included in the study. Testicular biopsy showed that they had impaired testicular maturation and were therefore at high risk for infertility. Fifteen of the 30 unilateral cryptorchid boys were treated with 10 µg LH-RHa (Buserelin) nasal spray, administered on alternate days for a period of 6 months, following orchiopexy. The control group consisted of 15 cryptorchid boys who had been treated by Schoemakers type of orchiopexy, alone. After puberty, the ejaculates of both groups were analyzed. RESULTS: All males in the untreated group were severely oligospermic, with 20 percent being azoospermic. In contrast, 86 percent of the treated ex-cryptorchid males had a sperm concentration within the normal range; this was significantly different from the sperm concentration found in the untreated group (p = 0.000008). CONCLUSION: For the first time, we demonstrate that infertility in cryptorchidism can be successfully corrected when suitably treated with a LH-RHa. Sperm parameters normalized following therapy in the majority of cryptorchid males who, untreated, would have remained infertile. This innovative hormonal treatment will have a profound effect on the current recommended surgical treatment of boys with undescended testes.

Comparison of Clinical Efficacy between a Single Administration of Long-Acting Gonadotrophin-Releasing Hormone Agonist (GnRHa) and Daily Administrations of Short-Acting GnRHa in In Vitro Fertilization-Embryo Transfer Cycles

This study was aimed to evaluate the efficacy of a single administration of long-acting gonadotrophin-releasing hormone agonist (GnRHa) as compared with daily administrations of short-acting GnRHa in controlled ovarian hyperstimulation (COH) for in vitro fertilization and embryo transfer (IVF-ET) cycles. The mean dosage of recombinant follicle-stimulating hormone (rFSH) required for COH (2,354.5+/-244.2 vs. 2,012.5+/-626.1 IU) and the rFSH dosage per retrieved oocyte (336.7+/-230.4 vs. 292.1+/-540.4 IU) were significantly higher in the long-acting GnRHa group (N= 22) than those in the short-acting GnRHa group (N=28) (p<0.05). However, the mean number of visit to the hospital that was required before ovum pick-up (3.3+/-0.5 vs. 22.2+/-2.0) and the frequency of injecting GnRHa and rFSH (12.8+/-1.2 vs. 33.5+/- 3.5) were significantly decreased in the long-acting GnRHa group (p<0.0001). The clinical pregnancy rate, implantation rate, and early pregnancy loss rate were not significantly different between the 2 groups. So, we suggest that a single administration of long-acting GnRHa is a useful alternative for improving patient's convenience with clinical outcomes comparable to daily administrations of short-acting GnRHa in COH for IVF-ET cycles.

effect of LH and GnRH analogues on induction ovulation in Bactrian camel [Camelus bactrianus]

Ovarian follicle response and corpus luteum formation following induction of ovulation using gonadotropin-releasing hormone [GnRH] analogues and luteinizing hormone [LH] in Bactrian camel were characterized. Bactrian camels with a mature follicle [13-19.6 mm] received: 1] natural porcine LH [25 mg, IV, n = 4], 2] Buserelin [20 microg, IV, n = 4] and 3] Alarelin [25 microg, IM, n = 4]. Daily ultrasonography and blood samplings were conducted between day -3 and +15 of the experiment [day 0 = Induction of ovulation]. Data were analyzed by univariat analysis with repeated measures analysis included in the model. Following treatment, mature follicle ovulated within 2 days and a new follicle wave emerged after 2-3 days. New mature follicle reached a size of 13.5 +/- 0.14 mm by day 12. Corpus luteum was detected on day 6 and reached the maximum size of 19.73 +/- 0.81 mm on day 9. Progesterone concentration initiated to increase on day 5, reached maximum concentration on day 9 and decreased significantly on day 11. In conclusion, due to the lack of significant difference among treatment groups [P>0.05], Alarelin may be considered as a drug of choice for inducing ovulation in Bactrian camel because of its effectiveness, simple route of administration [IM vs. IV], lower price, and local availability

Pretreatment with an oral contraceptive reduces the incidence of functional ovarian cyst formation during pituitary suppression by gonadotropins releasing hormone agonists and reduces the time required to achieve pituitary suppression

To assess the effect of pretreatment with combined oral contraceptive pills on ovarian cyst formation during pituitary suppression with buserelin acetate. Prospective study. Seventy six patients [76] who were undergoing IVF ET treatment. Patients in the study group [39] were pretreated with a combined oral contraceptive [OC] for 14 days starting on the second day of menstruation. The administration of buserelin acetate was initiated following the last day of OC administration. Patients in the control group [37] began to receive buserelin acetate on day 2 of menstruation. Ultrasound scans and hormonal assays were performed on the first day of menstruation, 7days after the commencement of buserelin acetate administration and every 4 days thereafter until pituitary suppression was achieved. After 7 days of GnRH-a administration, cysts were found in 3 patients in the study group compared to 12 cases in the control group. These numbers decreased to 1 and 7 cases after 14 days of agonist use. Three cases in the control group required surgical aspiration as the cysts persisted for 21 days after agonist use. Patients in the study group required a significantly shorter period of GnRH-a administration [12.6 days] [range 8-16 days] compared to [16.3 days] [range 11-21 days] in the control group. Days of gonadotropins stimulation and total number of ampoules required to achieve follicular response were significantly less in the study group [10.2 days and 41.2 ampoules] compared to [13.2 days and 53.2 ampoules] in the control group. Patients who were pretreated with the OC achieved marginally higher E2 levels on the day of hCG administration, 1,636 [1,166-3,311] compared to 1,538 [965-2,200] pmol/L in the control group. The patients in the study group produced higher numbers of developed follicles [10.2 versus 9.2], oocytes collected [9.4 versus 8.5], fertilization rate, [80.2% versus 78.2%] and number of good embryos available for transfer [6.3 versus 6.1] but the difference was not significant. Pretreatment with an OC abolishes ovarian cyst formation, shortens the time required to achieve pituitary suppression, and decreases gonadotropins requirements without having a negative effect on pregnancy rates

Buserelin acetate implants in the treatment of pain in endometriosis.

OBJECTIVE: To examine the treatment of pain in endometriosis by buserelin acetate implants. DESIGN: Fourteen patients with laparoscopically confirmed pelvic endometriosis were included in the study. All presented with severe dysmenorrhea with or without deep dyspareunia and pelvic pain. Buserelin acetate 6.6 mg. Implants were injected subcutaneously in the lateral region of the anterior abdominal wall, 3 doses every 8 weeks in group 1 (n=7) and 2 doses every 12 weeks in group 2 (n=7). Bone mineral density (BMD) was measured at the lumbar spine by dual energy X-ray absorptiometry (DEXA) before initiation of treatment and 1 year after. Symptoms, pelvic examination, ultrasonogram and serum estradiol were recorded every 4 weeks until two regular menses were established. RESULTS: All the painful symptoms were relieved and eventually disappeared in every patient within 4-6 weeks. Mean duration of amenorrhea in group 1 (408.4+/-47.7 days) was significantly longer than group 2 (331.3+/-22.4 days), p < 0.01. Mean duration of first observed side effects was 2.7+/-1.6 weeks. Hot flushes were the most common side effects. Serum estradiol levels were below 15 pg/ml in all patients and there were no significant differences between the two groups during amenorrhea. There was significant bone loss in both groups, 6.49+/-4.90 per cent in group 1 and 7.71+/-5.67 per cent in group 2. However, there were no significant differences between the two groups for lumbar BMD before and after treatment. CONCLUSION: Buserelin acetate implants are effective in the treatment of pain in endometriosis. These implants should have an important clinical application when chronic treatment is indicated. Further study is needed to design how this preparation should be used to minimize the adverse effects.

La buserelina en programas de superovulación para transferencia de embriones / Buserelin in superovulation programs for embryo transfer

El objetivo de éste trabajo fue comparar la respuesta superovulatoria y la cantidad y calidad de embriones recuperados en vacas Holstein en la Sabana de Bogotá, mediante la aplicación de buserelina en el día 6 del ciclo estral, antes de iniciar el esquema de superovulación . El trabajo se realizó en la Sabana de Bogotá, a 2640 msnm y una temperatura promedio de 12° C. Se emplearon veinte bovinos hembra de la raza Holstein a los cuales se les aplicó FSH (Vetrepharm Inc, Ontario,Canadá) para inducir superovulación, en los dias 11, 12 13 y 14 del ciclo estral, con una dosis total de 20 cc, y PGF2a (Pharmacia & Upjohn, Kalamazoo, MI, USA) con la última dosis de FSH, 3 cc im. A diez de ellas (grupo tratamiento) se les aplicó Buserelina (Hoechst Roussel Vet, München, Alemania) en el día 6 del ciclo estral, antes de iniciar el tratamiento superovulatorio. Las diez vacas restantes se consideraron como grupo control. Los resultados obtenidos muestran que hubo diferencia ssgnificativa entre el grupo tratamiento y el grupo control respecto a la respuesta superovulatoria (p< 0,05) No se encontró diferencia significativa en el número de embriones recuperados en ambos grupos (p> 0,05).

Lecirelin and Buserelin (Gonadotrophin releasing hormone agonists) are equally effective for fixed time insemination in buffalo

Buffalo has peculiar reproductive patterns, which make artificial insemination programs a hard and expensive task. Artificial insemination in fixed time is advantaged because females show low incidence of homosexual behaviour and strong dominance relationships, which leads to a poor accuracy in estrus detection. The aim of this experiment was to compare the efficiency of two different GnRH agonists in the GnRH/PGF2alpha/GnRH protocol (Buserelin vs Lecirelin). Two hundred and seventy buffaloes with 45 to 60 days postpartum were synchronized and fixed-time inseminated. The animals were kept on pasture in two farms at Säo Paulo and Mato Grosso do Sul (Brazil). Cows in Group 1 (n = 132) received, intramuscularly, 20 æg of Buserelin at a random day of the estrous cycle and, seven days later, 15 mg of prostaglandin F2alpha. Two days after prostaglandin administration, 10 æg Buserelin were intramuscularly injected. Cows in Group 2 (n = 138) were treated with the same protocol, but with intra-muscular administrations of Lecirelin (50 æg in the first administration and 25 æg in the second). Artificial insemination was performed 16 hours after the last injection in both groups. Pregnancies were diagnosed by ultrasonography (Pie Medical 480, 5.0 and 7.5 MHz linear probe), 30 days after artificial insemination. Conception rates were not influenced by farm (P > 0.05) and were similar in both groups [Group 1: 47.0 percent (62/132); Group 2: 50.0 percent (69/138); P > 0.05]. Results show that Lecirelin is as efficient as Buserelin to synchronize ovulation for fixed-time artificial insemination in buffaloes

Estudio comparativo entre la estimulación ovárica con la asociación citrato de clomifeno-gonadotrofina menopáusica humana y otros tres ciclos en fecundación in vitro / Comparative study between ovaric stimulation with association of chlomiphene citrate-human menopausic gonadotropin and three other cycles in in vitro fertilization

Este artículo fue realizado con la finalidad de evaluar la utilidad de los ciclos que combinan citrato de clomifeno y gonadotrofina menopáusica humana comparativamente con otros tres protocolos de estimulación ovárica que incluyen: gonadotrofina menopáusica humana, buserelín y hormona folículo estimulante en pacientes sometidas a fecundación in vitro. Se estudiaron 188 pacientes considerando: edad, maduración de los ovocitos, presencia de fecundación, de embarazos clínicos, de gestaciones múltiples, de abortos y de embarazos viables. Los resultados indican que no hubo diferencias significativas en la edad de las mujeres incluídas en cada protocolo. En cambio, los tratamientos con citrato de clomifeno tuvieron ovocitos más inmaduros, menor porcentaje de fecundación y de embarazos clínicos, sin disminuir el riesgo de embarazos múltiples y de abortos. Por lo tanto, nuestras conclusiones desaconsejan el uso de este tipo de tratamientos, siendo preferible la utilización de protocolos con buserelín, en ciclos largos, asociados a gonadotrofinas

Inhibitory effect of spironolactone on the contractions of the rabbit uterine horn and the human myometrial strip.

The spontaneous contractions of the rabbit uterine horns and the human myometrial strips were stimulated by oxytocin and buserelin acetate in isolated preparations. Spironolactone application to these models produced inhibitory effects on the contractions. It is concluded that spironolactone has inhibitory effect on the rabbit uterine horn and the human myometrial strip contractions.

Supressäo hipofisária com altas doses do agonista do hormônio liberador de gonatrofinas / Pituitary suppresion with high dosage of gonadotropin releasing hormone agonist

Neste trabalho, quatro mulheres voluntárias, ovulatórias foram submetidas a administraçäo diária do agonista do hormônio liberador de gonadotrofinas (aGnRH). O aGnRH (Buserelin) foi administrado intranasal na dose de 900 ug/dia durante 12 dias dividio em 3 doses de 300 ug, iniciando-se as 8:00hs. Amostras sanguíneas foram colhidas diariamente, imediatamente antes da primeria dose do Buserelin (8:00hs), sendo que nos dias 1, 4, 8 e 12 foram colhidos 3 amostras adicionais 60, 120 e 180 minutos após a primeira amostra. Avaliaram-se os níveis plasmáticos do hormônio luteinizante (LH), hormônio folículo estimulante (FSH e estradiol (E2). A administraçäo do aGnRH resultou inicialmente numa grande liberaçäo do LH (média de 60 mUI/ml) e do FSH (média de 20 mUI/ml) no 2§ dia, com queda progressiva a partir do 3§ dia, com estabilizaçäo a partir do 7§ dia, em valores em torno de 10 mUI/ml para ambos hormônios. A desensibilizaçäo hipofisária já foi observada a partir do quarto dia do ciclo, visto que houve um aumento do LH, após a administraçäo do aGnRH, nas amostras colhidas aos 180 minutos de apenas 79,3 por cento no quarto dia, contra 1.642 por cento nas amostras do primeiro dia. Para o FSH o incremento do 1§ dia foi de 162 por cento contra 25 por cento do 4§ dia. Os níveis de E2 apresentaram queda de seus valores a partir do 7§ dia, sendo que mostraram-se abaixo de 60pg/ml no 12§ dia, apesar dos níveis de LH e FSH se situarem em torno de 10mUI/ml. Os resultados sugerem que embora mantenha níveis razoáveis circulantes de LH e FSH mesmo no 12§ dia, a partir do 4§ dia, a hipófise já seria refratária ao GnRH endógeno e que os níveis plasmáticos de LH e FSH näo deveriam ser considerados como parâmetros para avaliaçäo do tempo necessário para a supressäo hipofisária quando do uso do aGnRH

Treatment of endometriosis with gonadotropin releasing hormone agonist (buserelin).

The results of treatment of endometriosis with intranasal buserelin is convincing. The drug effectively suppresses serum estradiol to the menopausal level. Clinical improvement and regression of endometriotic lesions were observed during treatment. Thus, buserelin offers an alternative medical treatment of endometriosis. Further studies of the effects of GnRH agonist on bone mass are needed.

Utilizacion de un analogo de LH-RH subcutaneo e intranasal en el tratamiento de niñas con pubertad precoz central / Use of a LH-RH analogue subcutaneously and intranasally in the treatment of girls with central precocious puberty

Se presenta la experiencia en 5 pacientes de sexo feminino. Sus edades cronológicas oscilaron entre 1,3 y 6,8 años, con edades óseas entre 2,3 y 11,6 años. Las dosis empleadas fueron: 25 microng/kg/dSC y posteriormente 1200 microng/dIN. En 2 niñas se administraron 159 mg de medroxiprogesterona previo al análogo y una semana después. En un caso, se comenzó por via IN por reacción alérgica local a la inyección SC. El tratamiento osciló entre 3 y 21 meses. Se obtuvo una regreión completa del desarrollo mamario en 4 pacientes y parcial en 1. En 4/5 casos se pudo valorar la velocidad de crecimiento anual, observándose una reducción entre el 40 y 55% vs. pretratamiento, asociada a desaceleración de la maduración ósea y a un incremento entre 2 y 4,5cm en la predicción de talla adulta. Durante la terapéutica se obtuvo una reducción de los niveles de LH, FSH y estradiol hasta valores prepuberales, así como una ausencia de respuesta en la prueba de LH-RH. Concluímos que el Buserelin constituiría en recurso altamente efectivo en el tratamiento de esta patoloía, siendo, al igual que otros análogos del LH-RH, recursos útiles que mejorarian la predicción de talla final