Buserelin Group Research Articles

Prostaglandin F2α treatment does not hasten ovulation in weaned sows

This study evaluated the efficiency of prostaglandin F2α (PGF) to hasten ovulation in weaned sows. In experiment I, weaned sows detected in estrus (0 h) received: no hormone (Control; n = 56); 0.5 mg PGF IM at 0 h and 2 h (PGF0; n = 56); or 0.5 mg PGF IM at 24 h and 26 h (PGF24; n = 55). In experiment II, weaned sows that did not express estrus signs until 72 h after weaning (0 h) were assigned to: no hormone (Control; n = 45); 10 µg buserelin acetate IM at 0 h (Buserelin; n = 43); 0.5 mg PGF IM at 34 h and 36 h (PGF; n = 44); or 10 µg buserelin acetate IM at 0 h plus 0.5 mg PGF IM at 34 h and 36 h (Buserelin + PGF; n = 45). In experiment I, no effect of PGF on the interval treatment onset to ovulation was observed (P > 0.05), and no treatment effect was observed on the relative or cumulative proportion of females that ovulated post-treatment onset (P > 0.05). In experiment II, treatment onset to ovulation interval was shorter for Buserelin group than for PGF group (P < 0.05), and a higher cumulative percentage of Buserelin treated sows ovulated up to 48 h compared to PGF and Control groups (P < 0.01), with no differences from Buserelin + PGF. Treatments did not affect total number of piglets born in both experiments (P > 0.05). In conclusion, PGF did not hasten ovulation timing or affect litter size in weaned sows.

P–761 Can modified luteal support in fresh cycle after agonist trigger “rescue” the cumulative live birth rate (CLBR) in high responders

Abstract Study question Can modified luteal support in fresh cycle “rescue” the cumulative live birth rate (CLBR) in high responders who receive agonist trigger? Summary answer Live birth rate in high responders who had agonist trigger in fresh cycle was significantly reduced despite modified luteal support. What is known already Previous studies, including small randomised controlled trials, claimed that good live birth rate could be achieved at fresh transfer in “high responders” who had GnRHa trigger with modified luteal phase support. However, majority of these studies exclude the true high responders (patients with 20 and above oocytes) and average number of collected eggs reported in many of these studies in the range of 9 to 12. The data on outcome of fresh transfer in true high responders is very limited. Study design, size, duration A prospective observational study was conducted in 407 patients, aged 23–42 years who were expected to be at risk of high response (AFC&amp;gt;18, AMH&amp;gt;20 pmol/l) undergoing controlled ovarian stimulation between 2014–2019 triggered either with HCG or GnRH agonist. Live birth rate (LBR) in a fresh and subsequent 3 frozen transfers were compared in groups with different triggers and freeze all. Participants/materials, setting, methods Patients were stimulated in short antagonist protocol. The trigger was chosen based on the background characteristics, peak oestradiol and clinician discretion. Triggering was achieved either with 0.5 mg buserelin (GnRHa) 0.5mgin 230 patients (A) or with 250 mcg of hCG(H) in 177 patients. Modified luteal support included vaginal progesterone, oral oestrogen and 1500 iu of hCG on the day of egg retrieval. The later was omitted with more than 20 oocytes. Main results and the role of chance The mean age, AFC, number of previous cycles, number of embryos transferred were 33.3, 22.4, 0.26 and 1.2 respectively and did not have significant difference between different triggers. Whereas AMH (53 pmol/l (A) vs 43.1 pmol/l (H), P = 0.003), peak oestradiol (15140.74 (A) vs 9738.59 (H), P = 5.59X10–14), and number of oocytes collected (21 vs.17, P = 5.63X10–7) were significantly higher in GnRHa group. Seventeen patients in buserelin group had elective freeze all. Ovarian Hyperstimulation Syndrome (OHSS) rate was 3.9% in buserelin group (more then half of these cases had a bolus of hCG at egg collection; most were mild/moderate). On the other hand, hCG group had 2.5% of OHSS (all severe). Live birth rate in fresh cycle was 31% in hCG and 21% in GnRHa groups. If freeze all was undertaken in fresh cycle after GnRHa trigger, then LBR in the first frozen cycle of this group was 53% (P = 0.003, fresh vs frozen GnRHa group). CLBR was not different between GnRHa and hCG groups (51%). However, this was significantly lower than CLBR in GnRHa trigger freeze all group 76% (P = 0.03) Limitations, reasons for caution The limitation of this study is its non-randomised nature. However, since it is one of the biggest studies for high responders it has a power to minimise bias by adjusting for multiple variables. Wider implications of the findings: Proceeding with fresh transfer in high responders after GnRHa trigger with modified luteal support not only maintains the risk of OHSS (equivalent to hCG group) but also significantly impairs the LBR not compensated even after 3 subsequent frozen embryo transfers. Therefore, freeze-all approach should be preferred in this group. Trial registration number NA

Effects of buserelin administration on testicular blood flow and plasma concentrations of testosterone and estradiol-17β in rams

This research aimed to examine for the first time the impact of single dose administration of gonadotropin-releasing hormone (GnRH) analog buserelin acetate on the testicular blood flow measurements (peak systolic velocity [PSV], end-diastolic systolic velocity [EDV], resistive index [RI], and pulsatility index [PI]) and the plasma steroids (testosterone and estradiol-17β) concentrations in rams. For this purpose, twelve adult Ossimi rams were randomly assigned into the buserelin group (n = 8) and were injected intravenously (iv) with buserelin acetate (0.008 mg/ram), whereas the remaining rams (n = 4) were injected with normal saline iv and served as a control group. Blood sampling and testicular pulsed-wave Doppler scanning were conducted immediately before (0) and 1, 3, 6, 24, 48, 72, 120, and 168 h after treatment. The control group did not reveal any substantial changes (P > 0.05) in the examined parameters, except for the EDV (P < 0.05). In the buserelin-treated group, a marked reduction in RI and PI values (P < 0.05) occurred 1 to 3 h after administration of buserelin. Besides, there was a significant increase in testosterone plasma concentrations following buserelin treatment. In conclusion, the administration of buserelin triggered a series of substantial changes in the testicular blood perfusion and steroidogenesis that could have a positive effect on testicular function in rams.

The Effects of Annatto Tocotrienol on Body Composition and Serum Adiponectin, Leptin and Glucose Level in a Rat Model of Androgen Deficiency Induced by Buserelin

Androgen ablation therapy using gonadotropin-releasing hormone agonists is reported to be associated with metabolic abnormalities. Annatto tocotrienol (AnTT) is reported to reduce the expression of genes related to adipogenesis but the mechanism remains elusive. This study sought to determine the effects of annatto tocotrienol on body composition (lean and fat mass), serum adiponectin, leptin, and glucose levels in male rats treated with buserelin, a testosterone ablation agent. Three-month-old male Sprague Dawley rats (n=32) were randomly divided into four groups. The normal control (n=8) was given corn oil orally daily and normal saline subcutaneously daily. The remaining groups were injected with buserelin subcutaneously (75µg/kg/day). The buserelin group (n=8) was given corn oil orally, while the treatment groups were supplemented orally with AnTT at 60 or 100 mg/ kg (n = 8/group). After treatment of 12 weeks, rats were euthanized. Dual-energy x-ray absorptiometry was performed to determine the lean and fat mass of the rats. Blood was collected for the evaluation of adiponectin, leptin and glucose levels. After 12 weeks, the lean mass, fat mass, adiponectin and leptin levels for all groups increased significantly compared to their respective baseline levels irrespective of their treatment (P<0.05). All groups, except rats receiving AnTT at 60 mg/kg, experienced a significant increase in glucose level after 3 months (P<0.05). Androgen ablation and AnTT do not influence body composition, adiponectin and leptin levels in male rats. However, annatto tocotrienol at 60 mg/kg may improve glucose metabolism.

Kisspeptin Modulates Luteinizing Hormone Release and Ovarian Follicular Dynamics in Pre-pubertal and Adult Murrah Buffaloes.

Kisspeptin is a neuropeptide that governs the reproductive axis upstream to GnRH. We wanted to study whether kisspeptin modulates plasma LH and FSH levels and ovarian follicular dynamics in buffaloes and whether kisspeptin can be used for fixed time artificial insemination (FTAI). We carried out these studies in comparison with buserelin, a potent GnRH agonist. Kisspeptin dose-dependently increased plasma LH levels. However, the kisspeptin-induced increase in LH was short-lived as the peak reached in 15–30 min returned to basal values by 1–2 h. The kisspeptin-induced increase in LH level was less compared to buserelin-induced increase in LH level which sustained over time. Kisspeptin did not enhance FSH release while buserelin resulted in a gradual increase over time. LH response to repeated injections of kisspeptin was greater than that induced by buserelin. While buserelin induced an increase in the number of follicles, kisspeptin induced an increase in the growth rate of the follicle. In adult cycling animals, while both the drugs increased plasma LH levels, the increase was greater in buserelin group compared to kisspeptin group. In contrast to the findings in pre-pubertal animals, kisspeptin induced an increase in both the number as well as the size of follicles compared to buserelin. Our studies on oestrus synchronization, using either kisspeptin-PGF2α-kisspeptin protocol or buserelin-PGF2α-buserelin Ovsynch protocol on day 0, 7, and 9, respectively, revealed that kisspeptin increased the number of follicles at wave emergence and the diameter of dominant follicle after 2nd dose of drug, the oestrus response rate and duration of oestrus, compared to buserelin. However, conception rate was not significantly different among the groups. From our studies, it appears that Kp and Buserelin differentially modulate follicular dynamics depending on the reproductive age of the animals.However, studies in a larger herd are required to confirm whether kisspeptin can be used for oestrous synchronization in buffaloes.

Induction of Ovulation in Mangalarga Marchador Mares by hCG or GnRH

Background: Induction of ovulation is a key procedure for horse assisted reproduction technologies, such as for artificial insemination (AI) and embryo transfer. The application of hCG remains as the primary ovulation-inducing agent for horse assisted reproduction, but alternatives are in demand to avoid its adverse effects, such as loss of ovulation-inducing ef­ficiency over multiple applications by hCC-antibody production. Despite reports on alternative ovulation-inducing agents, pair-wise comparisons of such agents under similar conditions have been limited. Under such scenario, the work was aimed to determine the efficiency of both hCG and Buserelin at inducing ovulation in Mangalarga Marchador mares raised in the Northeast of Brazil under an AI program.Materials, Methods &amp; Results: Mares were initially selected based on their reproductive performance, the absence of clinical-reproductive alterations and adequate body condition score. Mares in diestrus were randomly distributed in three experimental conditions, received 5 mg of Dinoprost and were monitored daily for estrus detection. After estrus detection, ovaries were monitored by ultrasonography, in 12-h intervals, until the follicle reached 35 mm. At this time-point, ovula­tion was induced with 0.042 mg of Buserelin endovenously, with 3,000 IU hCG by an intramuscular shot, and control mares received 2 mL of saline solution, also by an intramuscular shot. Both hCG and Buserelin displayed similar efficien­cies (P &gt; 0.05) for induction of ovulation and that both agents were effective (P &lt; 0.05) for such purpose, since greater percentages (P &lt; 0.05) of induction on mares treated from those of the control. Moreover, the total number of ovulations in mares treated at the end of the experiment was not different (P &gt; 0.05) from those found in the Control. All ovulations occurred within a 72-h period after treatment. It can be observed that in mares treated with hCG or Buserelin, ovulations occurred both in more mares (P &lt; 0.05) and at earlier time-points than mares from the control. It is also possible to note that pregnancy was not different (P &gt; 0.05) between hCG and Buserelin groups, and that pregnancy of mares treated with ovulation-inducing factors was similar to the control.Discussion: The majority of ovulations in mares occurred within initial 48-h after treatment for both hCG and GnRH, suggesting a similar potential for horse assisted reproduction. Both hCG and Buserelin are two commonly used agents for induction of ovulation in mares. As described here, the majority of ovulations occurred within initial 48-h after treatment, a fact which can be attributed to hCG and GnRH activity, since it can happen in intervals from 36 to 48-h after treatment. Pregnancy rates did not differ among groups. These results are under the working hypothesis that hCG and Buserelin would display similar efficiencies on pregnancy rates. Despite the understanding of hCG activity on induction of ovulation due to its high specificity toward LH receptors and results from a direct effect on diminishing estradiol concentration, increasing LH, and further inducing ovulation within 48-h after treatment. In contrast, Buserelin has a similar functional property but acts upon LH synthesis and its release. In conclusion, ovulation in mares can be induced with both hCG and Buserelin, and both ovulation-inducing agents do not affect pregnancy rates.Keywords: gonadotropin, releasing factor, ovary, follicle, corpus luteum.

Induction of Ovulation in Mangalarga Marchador Mares by hCG or GnRH

Background: Induction of ovulation is a key procedure for horse assisted reproduction technologies, such as for artificial insemination (AI) and embryo transfer. The application of hCG remains as the primary ovulation-inducing agent for horse assisted reproduction, but alternatives are in demand to avoid its adverse effects, such as loss of ovulation-inducing efficiency over multiple applications by hCC-antibody production. Despite reports on alternative ovulation-inducing agents, pair-wise comparisons of such agents under similar conditions have been limited. Under such scenario, the work was aimed to determine the efficiency of both hCG and Buserelin at inducing ovulation in Mangalarga Marchador mares raised in the Northeast of Brazil under an AI program.Materials, Methods &amp; Results: Mares were initially selected based on their reproductive performance, the absence of clinical-reproductive alterations and adequate body condition score. Mares in diestrus were randomly distributed in three experimental conditions, received 5 mg of Dinoprost and were monitored daily for estrus detection. After estrus detection, ovaries were monitored by ultrasonography, in 12-h intervals, until the follicle reached 35 mm. At this time-point, ovulation was induced with 0.042 mg of Buserelin endovenously, with 3,000 IU hCG by an intramuscular shot, and control mares received 2 mL of saline solution, also by an intramuscular shot. Both hCG and Buserelin displayed similar efficiencies (P &gt; 0.05) for induction of ovulation and that both agents were effective (P &lt; 0.05) for such purpose, since greater percentages (P &lt; 0.05) of induction on mares treated from those of the control. Moreover, the total number of ovulations in mares treated at the end of the experiment was not different (P &gt; 0.05) from those found in the Control. All ovulations occurred within a 72-h period after treatment. It can be observed that in mares treated with hCG or Buserelin, ovulations occurred both in more mares (P &lt; 0.05) and at earlier time-points than mares from the control. It is also possible to note that pregnancy was not different (P &gt; 0.05) between hCG and Buserelin groups, and that pregnancy of mares treated with ovulation-inducing factors was similar to the control.Discussion: The majority of ovulations in mares occurred within initial 48-h after treatment for both hCG and GnRH, suggesting a similar potential for horse assisted reproduction. Both hCG and Buserelin are two commonly used agents for induction of ovulation in mares. As described here, the majority of ovulations occurred within initial 48-h after treatment, a fact which can be attributed to hCG and GnRH activity, since it can happen in intervals from 36 to 48-h after treatment. Pregnancy rates did not differ among groups. These results are under the working hypothesis that hCG and Buserelin would display similar efficiencies on pregnancy rates. Despite the understanding of hCG activity on induction of ovulation due to its high specificity toward LH receptors and results from a direct effect on diminishing estradiol concentration, increasing LH, and further inducing ovulation within 48-h after treatment. In contrast, Buserelin has a similar functional property but acts upon LH synthesis and its release. In conclusion, ovulation in mares can be induced with both hCG and Buserelin, and both ovulation-inducing agents do not affect pregnancy rates.

197 The Effect of Gonadotropin-Releasing Hormone Agonist on Superovulation and Estrous Synchronization in Female Sprague Dawley Rat

A large number of oocytes and adequate recipient conditions are required to produce genetically modified rats by embryo transfer. In this study, we investigated the effect of a synthetic gonadotropin-releasing hormone (GnRH) agonist, buserelin, on (1) superovulatory response in donor rats, and (2) oestrous cycle synchrony in recipient female Sprague Dawley rats at 8 weeks of age. First, for superovulation, donors were divided into 2 groups: control and buserelin injection group (42 μg mL−1). Superovulation was performed in both groups by injection of pregnant mare’s serum gonadotropin (PMSG, 150 IU) at Day −3 and human chorionic gonadotropin (hCG, 150 IU) at Day −1 (Day 0 = oocyte collection). In addition, the buserelin group was given 42 μg mL−1 buserelin on Day −4. Oviduct and ampulla were removed surgically to collect the oocytes. As results, more ovulations were detected in the 42 μg mL−1 buserelin group (6.18 ± 1.10 oocyte/rat, n = 240) than in the control group (5.06 ± 0.82 oocyte/rat; n = 124; t-test P = 0.038). Second, 2 groups were set up to investigate the effect of administration of buserelin on synchronizing the oestrus cycle of recipients. Because the oestrous cycle of the rat was 4 to 5 days, we examined the difference of vaginal impedance between the 2 groups on Day 4 after injection and checked whether there was a significant difference in the synchronization of the oestrous cycle. An impedance value &gt;3.0 kΩ was considered as an indication for proestrus stage; therefore, we analysed the data &gt;3.0 kΩ in both groups. In results, the incidence of proestrus was significantly increased in buserelin injection group (n = 128) than in the control group (n = 70). In addition, there was a significant difference in mean impedance in the 2 groups (buserelin injection group: 4.25 ± 3.79 kΩ; control group: 1.43 ± 1.20 kΩ; P &lt; 0.005). In conclusion, administration of 42 μg mL−1 buserelin had a beneficial effect on oocyte ovulation and oestrous synchronization, and it will be usefully applied in the production of transgenic rats.

Identification of beta-nerve growth factor in dromedary camel seminal plasma and its role in induction of ovulation in females

The main objective of this study was to demonstrate the effect of seminal plasma ovulation inducing factor (OIF) on ovulation in female camels. Seminal plasma was fractionated using gel filtration chromatography, and two protein peaks were obtained and analysed by western blotting. The effect of the bioactive protein fraction (OIF/β-NGF) was tested by intramuscular injection (1 ml) in synchronized females with the following treatments: PBS (negative control group, n = 3); 20 µg Buserelin (GnRH analogue, positive control group; n = 3); and purified OIF with doses of 1 and 2 mg (n = 5, each treatment). Blood samples were collected every two days from day 0 until 14 days post-treatment, and the progesterone concentration was assessed. The obtained results showed that the OIF is highly present in the seminal plasma of dromedary camels as a protein with a molecular mass of approximately 14 kDa. It was detected as a beta-Nerve Growth Factor, named Cam-β-NGF. The effect of this molecule on ovulation was clearly demonstrated by the significant increase of the plasma progesterone concentration in the treated female groups (1 and 2 mg of Cam-β-NGF) as observed in Buserelin group. In summary, intramuscular injection of β-NGF isolated from dromedary camel seminal plasma induces ovulation in females with similar rate to Buserelin treatment.

The effect of short-term treatments of a gonadotropin- releasing hormone analog (buserelin) on sciatic nerve regeneration

Summary Gonadotropin-releasing hormone (GnRH) has neuromodulatory roles in central and peripheral nervous systems. The purpose of this study is to evaluate the effect of GnRH analog (buserelin) on peripheral nerve regeneration. Forty adult male rats were divided into buserelin-treated, normal saline, sham surgery, and castrated + buserelin groups. The left sciatic nerve was crushed by a fine forceps and all animals were evaluated by sciatic functional index (SFI), electrophysiology, histology and immunohistochemistry testing. On post operation days 21 and 28, the difference between buserelin and normal saline groups was statistically significant (P 0.05). At the 28th day after operation, the diameters (µm) of the regenerated myelinated fibers of the buserelin group were significantly greater than those of the normal saline group (P<0.05). Although nerve conduction velocity (NCV) of the buserelin group was faster than the normal saline group, the difference was not statistically significant. The present study suggests that buserelin treatment might accelerate peripheral nerve regeneration.

160 CONCEPTION RATES FOLLOWING TREATMENT OF LACTATING HOLSTEIN RECIPIENTS WITH A GONADOTROPIN RELEASING HORMONE (GnRH) ANALOGUE AT THE TIME OF TRANSFER OF OVUM PICK-UP/IVF-DERIVED EMBRYOS

The use of lactating dairy cows as ovum pick-up (OPU)/IVF-derived embryo recipients in large-scale embryo transfer programs may be limited by the effects of low progesterone concentrations on the uterine environment and subsequent embryo development. It was hypothesized that the injection of a GnRH analogue on the day of embryo transfer would induce ovulation and formation of an accessory corpus luteum, increasing progesterone concentrations and, as a result, conception rates. An experiment was designed to evaluate the effects of two different GnRH analogues injected IM on the day of embryo transfer on conception rates of lactating Holstein recipients. Oestrus was not synchronized and was detected continuously by multiple observers during the day and in the evening until midnight. Recipient days in milk varied from 45 to 150, daily milk production ranged from 20 to 45 kg, body condition scores and age ranged from 2.5 to 4.5 and 2.5 to 5.5 years, respectively. Herd pregnancy rates after the first artificial insemination ranged from 15% to 70%, considering the period the experiment was conducted. Embryos were produced by standard in vitro techniques following OPU on Holstein donors. Lactating Holstein recipients (n = 224) were allocated randomly to one of three treatment groups 7 days after detected oestrus: Control (n = 77) = vehicle; Buserelin (Sincroforte®, Ouro Fino, Sao Paulo, Brazil; n = 75) = 10 µg; and Deslorelin (Sincrorrelin®, Ouro Fino; n = 72) = 750 µg. Embryos were transferred nonsurgically 6 to 8 days after observed oestrus. Pregnancy was detected by ultrasonography between 62 and 72 days after embryo transfer. Percent pregnant data were analyzed as a binomial distribution under the GENMOD procedure of SAS (SAS Institute Inc., Cary, NC, USA). Conception rates were similar (P = 0.13) between Control (28%, 22/77), Buserelin (24%, 18/75), and Deslorelin (38%, 28/72) treatment groups. These data demonstrate that conception rates from in vitro produced embryos transferred to lactating dairy cows are not improved by treatment with a GnRH analogue on the day of transfer. Although not critically tested, results indicate that adequate conception rates may be obtained in commercial dairy operations from OPU/IVF-derived embryos, adding an important management tool for reproduction and animal breeding enhancement.

Rabbit reproductive performance after insemination with buserelin acetate extender

Rabbit farmers and insemination centres have established new requirements relating to males (genetic, nutritional and environmental factors) and rabbit insemination techniques. The aim of this study was to evaluate buserelin acetate on the reproductive performance of nulliparous, multiparous lactating and multiparous non-lactating does inseminated on three commercial farms. Two thousand two hundred and three commercial crossbred does belonging to three commercial farms were inseminated with pooled semen from males of two selected meat lines; R line (UPV rabbit selection centres, Spain) in farms 1 and 2, and PS Hyplus 59 line (Grimaud Frère, France) on farm 3. Ejaculates from 12–20 males from each line were pooled and diluted to twelve million sperm per millilitre by adding TRIS–citrate-extender. Diluted semen from each male line was split into two fractions, the first without buserelin acetate added to semen (Control group) and the second fraction was supplemented with 10 μg of buserelin acetate per millilitre (Buserelin group). Receptive females (red colour of vulvar lips) were inseminated with 0.5 mL using a standard plastic curved pipette. Artificial insemination with semen extended with buserelin resulted in lower pregnancy and kindling rates irrespective of the physiological status of females or the farm (78.7% and 76.0% vs 85.8% and 83.4%, buserelin extender group and control respectively, P<0.01), although does from both treatment groups had a similar litter sizes (10.4 and 9.6 total and alive born, respectively). This study opened up new prospects for changing rabbit insemination procedures.

A Single Subcutaneous Administration of Buserelin Induces Ovulation in the Mare: Field Data

The aim of the present study, was to evaluate whether a single subcutaneous administration of the GnRH analogue buserelin could induce ovulation in the mare during the breeding season. Two studies were carried out under field conditions. In Experiment 1, 90 cycles of trotter mares aged 2-7 years, were assigned to a buserelin group (Bus1) or to a control group (Control), in the presence of a >/=35 mm pre-ovulatory follicle, with uterine oedema and a relaxed cervix. Ten mares were assigned to the two groups for 32 cycles in Bus1 and 52 cycles in Control, two mares received only Bus1 for three cycles, and one mare was assigned to Control for three cycles. Mares treated with buserelin received 6 ml of SUPREFACT s.c. (1.05 mg/ml buserelin acetate), and no treatment was given in Control. The ovulation rate between 24 and 48 h was higher (p < 0.0001) in Bus1 (31/35) than in Control (15/55). In Experiment 2, the condition of inducing ovulation with 6 ml SUPREFACT s.c. (Bus2) or 1500 ui human chorionic gonadotropin were identical to the first study. Forty-nine mares of ages 2-21 years, were used for 120 cycles, 56 cycles were assigned to Bus2, and 64 cycles were induced with 1500 IU human chorionic gonadotropin i.v. No significant difference was found in the ovulation rate on day 2 (38/56, 50/64), or in the fertility rate (19/48, 26/57). No negative effect of the treatment was observed with repeated buserelin administration in either study during the breeding season. We can conclude that a single administration of buserelin induces ovulation in the mare, under suitable conditions for veterinary practitioners.

Effectiveness of Buserelin Acetate for Triggering Endogenous LH Surge before Oocyte Retrieval in Clomiphene Citrate Cycle

The purpose of this study was to evaluate the effectiveness of buserelin acetate (BA) for triggering endogenous LH surge before oocyte retrieval in clomiphene citrate (CC) or CC hMG cycles. Patients were divided into two groups: a buserelin group, which consisted of patients treated with BA for 73 cycles 34–36 hours before oocyte retrieval, and an hCG group, which consisted of patients treated with hCG for 89 cycles 34–36 hours before oocyte retrieval. Rate of oocyte retrieval, ratio of metaphase II oocytes, fertilization rate in ICSI, fertilization rate in IVF, ratio of good cleaved embryos, rate of blastocyst development and pregnancy rate were 59.1%, 74.3%, 78.8%, 78.4%, 64.6%, 50.0% and 8.3%, respectively in the buserelin group and 63.2%, 71.3%, 80.6%, 67.6%, 58.6%, 66.7% and 12.5%, respectively, in the hCG group. There were no significant differences in those results between the groups. In conclusion, BA is present terse should be used for a conclusion effective for triggering LH surge before oocytes retrieval in CC or CC hMG cycles.

Cetrorelix in an oral contraceptive-pretreated stimulation cycle compared with buserelin in IVF/ICSI patients treated with r-hFSH: a randomized, multicentre, phase IIIb study

The aim of this study was to assess the non-inferiority of an oral contraceptive (OC)-pretreated cetrorelix regimen and a buserelin regimen in IVF/ICSI patients treated with r-hFSH in terms of total number of oocytes retrieved. Multicentre, randomized study. One hundred and eighty two patients were randomized to receive cetrorelix with OC pretreatment (n = 91) or to receive buserelin (n = 91). The cetrorelix group started with daily OCs on cycle day 5 and continued for 21-28 days. Cetrorelix (0.25 mg) was given daily from stimulation day 6 up to and including the day of r-hCG administration. The buserelin group started with buserelin (500 microg/day) for at least 10 days until down-regulation was achieved, after which the dose was reduced to daily 200 microg up to and including the day of r-hCG administration. r-hFSH was started in both groups on a Friday, in the cetrorelix group 5 days after the last OC pill intake. Both regimens were followed by a standard IVF or ICSI procedure. The primary efficacy endpoint was the number of oocytes retrieved per patient. Number of oocytes, cancellation rates, r-hFSH requirements, number of oocyte retrievals during the weekend or public holiday and number of pregnancies were similar in both groups. Both treatment regimens were well tolerated. Cetrorelix pretreated with OCs resulted in similar number of oocytes retrieved compared with a long buserelin protocol. Both regimens were well tolerated and allowed scheduling of the oocyte retrieval, with only small number of retrievals falling on a weekend or public holiday.

Comparison of outcome of clomiphene citrate/human menopausal gonadotropin/cetrorelix protocol and buserelin long protocol – a randomized study

This study evaluates the efficacy of a stimulation protocol with clomiphene citrate (CC)/human menopausal gonadotropin (hMG)/cetrorelix and its effects on oocyte quality and endometrium. One hundred and twenty couples with male-factor infertility who were about to undergo their first intracytoplasmic sperm injection cycles were randomized into two groups. Sixty women were stimulated with the CC/hMG/cetrorelix protocol (cetrorelix group) and 60 received the buserelin long protocol (buserelin group). Fewer oocytes were recovered in the cetrorelix group than in the buserelin group (mean ± standard deviation (SD): 11.1 ± 4.0 vs. 17.3 ± 5.8, p < 0.001); however, the percentages of metaphase II, metaphase I and germinal vesicle oocytes were similar between the two groups. Serum estradiol level was significantly lower in the cetrorelix than in the buserelin group (mean ± SD: 2600.58 ± 1189.11 vs. 3293.46 ± 1221.49 pg/ml, p = 0.006), but the endometrial thickness was similar. The implantation rates (19.2% vs. 17.7%) and the pregnancy rates (41.7% vs. 40.0%) were similar between groups. The ampoules (mean ± SD: 18.9 ± 3.0 vs. 38.9 ± 12.2, p < 0.001) and injections (mean ± SD: 6.8 ± 1.1 vs. 15.7 ± 3.1, p < 0.001) of gonadotropin used were significantly lower in the cetrorelix group than in the buserelin group. No patients in either group developed a premature luteinizing hormone surge. The present study found no statistically significant difference between the two treatment modalities with regard to pregnancy rates.

Long-term effects on bone mineral density and bone metabolism of 6 months’ treatment with gonadotropin-releasing hormone analogues in Japanese women: comparison of buserelin acetate with leuprolide acetate

Our objective was to assess the effects of 6 months' treatment with two types of gonadotropin-releasing hormone (GnRH) analogues on lumbar bone mineral density (BMD) and bone metabolism. We studied 27 women who had been given a diagnosis of endometriosis or uterine myoma. The subjects received drug therapy for 6 months and were subsequently followed up for 1 year. The BMD of the lumbar spine (L2, L3, L4) was measured by dual energy X-ray absorptiometry four times: at baseline, after 6 months, after 12 months, and after 18 months. The serum concentrations of sex steroids and bone metabolic markers were measured at the same times as BMD. Compared with the baseline value, the mean decrease in the buserelin group L2-4 BMD was 3.7% at 6 months, 1.7% at 12 months, and 0.4% at 18 months. In the leuprolide group, L2-4 BMD decreased respectively by 5.1%, 6.2%, and 4.3%. Serum concentrations of calcium increased significantly after 6 months of treatment (P < 0.05) and returned to the baseline level at 12 months in both groups. In the leuprolide group, the intact osteocalcin concentration after 6 months was significantly higher than the baseline value, and after 12 months, it decreased to the baseline level. Our results indicate that the effect on BMD of 6 months' treatment with GnRH analogues virtually resolves by 1 year after treatment, provided that drugs affecting bone metabolism are not given during this period.

Similar endometrial development in oocyte donors treated with either high- or standard-dose GnRH antagonist compared to treatment with a GnRH agonist or in natural cycles

This descriptive study evaluates the impact on endometrial development of standard and high doses of a GnRH antagonist in stimulated cycles compared with GnRH agonist and natural cycles. Thirty-one oocyte donors were treated with a combination of rFSH and 0.25 mg/day ganirelix (standard dose), 2 mg/day ganirelix (high dose) or 0.6 mg/day buserelin (long protocol). Vaginal progesterone (200 mg/day) was administered in the luteal phase. Endometrial biopsies were performed 2 and 7 days after HCG administration. Additional biopsies were carried out in a subset of 12 subjects, 2 and 7 days following the LH peak of their previous natural cycle. Biopsies were evaluated histologically and by scanning electron microscopy. Gene expression profiles were also studied. At HCG +2, all the parameters studied were similar in all the groups and comparable to those observed in the natural cycle. At HCG +7, endometrial dating, steroid receptors and the presence of pinopodes were comparable in both GnRH antagonist groups and in the natural cycle. In buserelin group, endometrial dating and pinopode expression suggested an arrested endometrial development. For window of implantation genes, expression patterns were closer to those in the natural cycle following standard- or high-dose ganirelix than after buserelin administration. No relevant alteration was observed in the endometrial development in the early and mid-luteal phases in women undergoing controlled ovarian stimulation for oocyte donation following daily treatment with a standard- or high-dose GnRH antagonist. In addition, the endometrial development after GnRH antagonist mimics the natural endometrium more closely than after GnRH agonist.

Doppler ultrasound measures of testicular blood flow in stallions

This research aimed to examine for the first time the impact of single dose administration of gonadotropin-releasing hormone (GnRH) analog buserelin acetate on the testicular blood flow measurements (peak systolic velocity [PSV], end-diastolic systolic velocity [EDV], resistive index [RI], and pulsatility index [PI]) and the plasma steroids (testosterone and estradiol-17β) concentrations in rams. For this purpose, twelve adult Ossimi rams were randomly assigned into the buserelin group (n = 8) and were injected intravenously (iv) with buserelin acetate (0.008 mg/ram), whereas the remaining rams (n = 4) were injected with normal saline iv and served as a control group. Blood sampling and testicular pulsed-wave Doppler scanning were conducted immediately before (0) and 1, 3, 6, 24, 48, 72, 120, and 168 h after treatment. The control group did not reveal any substantial changes (P > 0.05) in the examined parameters, except for the EDV (P < 0.05). In the buserelin-treated group, a marked reduction in RI and PI values (P < 0.05) occurred 1 to 3 h after administration of buserelin. Besides, there was a significant increase in testosterone plasma concentrations following buserelin treatment. In conclusion, the administration of buserelin triggered a series of substantial changes in the testicular blood perfusion and steroidogenesis that could have a positive effect on testicular function in rams.

Combined effects of lutenizing hormone-releasing hormone analogue with antiestrogen on rat mammary tumors

The efficacy of luteining hormone-releasing hormone (LH-RH) analogue, buserelin, combind with tamoxifen (TAM) on 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumors was investigated. Low-dose of TAM (L-TAM), 1 mg/kg daily, significantly suppressed the growth of tumors compared with no treatment group. High-dose of TAM (H-TAM), 10 mg/kg daily, suppressed growth considerably, and there was a significant difference in the antitumor effect between the L-TAM group and the H-TAM group. The combined treatment using buserelin and L-TAM significantly suppressed the tumor growth compared with the treatment using each single agent. LH-RH analogue actually reduced serum estradiol (E2) levels and enhanced the antitumor effect brought by a therapeutical dose of TAM. The reduction of serum cholesterol levels as a beneficial effect of TAM was reserved when combined with buserelin. Insulin-like growth factor 1 (IGF-1) expressions in tumors were significantly decreased in the buserelin and L-TAM group. These results support the usefulness of this combination in clinical use.