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PubMed2000

Combined treatment with buserelin and tamoxifen in premenopausal metastatic breast cancer: a randomized study.

BACKGROUND: Surgical or medical castration and antiestrogenic treatment with tamoxifen are common endocrine treatments for premenopausal women with breast cancer. However, tamoxifen therapy induces high levels of plasma estradiol, with unknown long-term effects. In this study, we investigated the effect of combining estrogen suppression with the luteinizing hormone-releasing hormone agonist buserelin and estradiol receptor blockade with tamoxifen to determine whether the high estradiol levels induced by tamoxifen could be reduced and whether the antitumor effects would be better. METHODS: In a three-arm, randomized, prospective trial, from 1988 through 1995, a total of 161 premenopausal patients with advanced breast cancer were randomly assigned to treatment with buserelin, tamoxifen, or both. Patients with steroid receptor-negative tumors or with tumors of unknown receptor status who had a disease-free interval of less than 2 years were excluded. The median follow-up was 7.3 years, during which 76% of the patients died, all of breast cancer. Patient and tumor characteristics were well balanced among treatment groups. All P values are from two-sided tests. RESULTS: Combined treatment with buserelin and tamoxifen was superior to treatment with buserelin or tamoxifen alone by objective response rate (48%, 34%, and 28% of patients who could be evaluated, respectively; P =.11 [chi(2) test]), median progression-free survival (9.7 months, 6.3 months, and 5.6 months; P =.03), and overall survival (3.7 years, 2.5 years, and 2.9 years; P =.01). Actuarial 5-year survival percentages were 34.2% (95% confidence interval [CI] = 20.4%-48.0%), 14.9% (95% CI = 3.9%-25.9%), and 18.4% (95% CI = 7.0%-29.8%), respectively. No differences in antitumor effects were observed between single-agent treatment groups. During combined treatment or treatment with buserelin alone, plasma estradiol levels were suppressed equally; in contrast, during treatment with tamoxifen alone, plasma estradiol levels increased threefold to fourfold over pretreatment levels. CONCLUSION: Combined treatment with buserelin and tamoxifen was more effective and resulted in longer overall survival than treatment with either drug alone.

Adult↗
PubMed1989

The use of a short regimen of buserelin, a gonadotrophin-releasing hormone agonist, and human menopausal gonadotrophin in assisted conception cycles.

The outcome of in-vitro fertilization treatment using buserelin, an agonist of luteinizing hormone releasing hormone, given in a short stimulation regimen with human menopausal gonadotrophin (HMG), was compared with a conventional regimen including clomiphene citrate (CC). A total of 94 infertile women underwent cycles of treatment with intranasal buserelin, 500 micrograms daily from the first day of menstruation and also HMG daily from the third day. The same patients had previously undergone unsuccessful treatment cycles with CC and HMG. Overall, addition of buserelin resulted in fewer cycles being abandoned (10 versus 34%) and none of the patients ovulated prior to collection. The mean total dose of HMG required was increased by 74% in buserelin cycles. Significantly more oocytes were collected with buserelin treatment (mean 5.9 versus 4.4, P less than 0.01) and, thus, significantly more embryos were transferred (mean 2.3 versus 1.2, P less than 0.0001) although fertilization and cleavage rates were unchanged. Fifteen pregnancies were achieved, giving a clinical pregnancy rate of 22% per embryo transfer. These pregnancies resulted in 16 live births (7 singletons, 3 twins, 1 triplets). Four pregnancies failed before 14 weeks gestation. We conclude, therefore, that the substitution of buserelin for CC for ovarian stimulation in poor responders results in an improved outcome, both in terms of the number of oocytes collected and the pregnancy rate per treatment cycle.

Administration, Intranasal↗
PubMed1997

Potentiating effect of buserelin acetate, an LHRH agonist, on the proliferation of ventral prostatic epithelial cells in testosterone-treated castrated rats.

BACKGROUND: We used buserelin acetate ([D-Ser(But)6] LHRH ), an LHRH agonist and strong blocker of LH secretion, as a treatment for prostatic cancer. It is possible that this LHRH agonist has a proliferative effect on the prostate in addition to suppressing LH secretion. The purpose of this study was to examine the proliferative effect of LHRH agonist on rat prostatic epithelial cells. METHODS: We determined the optimal dose of testosterone necessary to maintain a positive level of proliferating cell nuclear antigen (PCNA) in the ventral prostatic epithelial cells of castrated Wistar rats. Testosterone-treated rats then received various doses of buserelin acetate. Castrated rats without exogenous testosterone also received buserelin acetate. The PCNA positivity was determined by immunohistochemistry with anti-PCNA monoclonal antibody. RESULTS: The optimal dose of testosterone enanthate was 4 mg at 0 and 28 days after castration. Administration of buserelin acetate on day 0 and 28 in doses of 0.16 mg to 1.28 mg significantly increased PCNA positivity in a dose-dependent manner. Administration of buserelin acetate to castrated rats without testosterone also increased PCNA positivity but there was no statistical significance. CONCLUSIONS: Buserelin acetate has a potentiating effect on the proliferation of ventral prostatic epithelial cells of castrated rat in the presence of a physiological level of exogenous testosterone. This effect may slightly influence the result of hormonal therapy by LHRH agonist.

Animals↗
PubMed1991

[Effects of buserelin presurgical treatment on vascularity in the sub-serosal interstitial tissue of the uterus and operative blood loss at hysterectomy in women with uterine leiomyoma and adenomyosis].

We examined 194 cases of uterine leiomyoma and adenomyosis who received total abdominal hysterectomy, in order to compare the effect of presurgical medical treatment such as with Buserelin, Danazol and Pill, on operative blood loss with non-treated group. The operative blood loss was 314.0 +/- 177.2 ml (mean +/- SD) in the control group (n = 145), 211.2 +/- 64.1 ml in the Buserelin-treated group (n = 26), 276.8 +/- 110.7 ml in the Danazol-treated group (n = 10), and 396.6 +/- 213.1 ml in the Pill-treated group (n = 13). The operative blood loss in the Buserelin-treated group was significantly lower than in the control group (p less than 0.01) and in the Pill-treated group (p less than 0.05). After considering the pathology of the uterus, the uterine size, and the level of expertise of the surgeon, the operative blood loss in the Buserelin-treated group was significantly lower than in the control group. We measured the capillary space, small arteries and veins in the sub-serosal interstitial tissue of the uterus, and observed that the vascular space decreased significantly (p less than 0.01) in the Buserelin-treated group compared to the control group. From these facts it may be concluded that Buserelin presurgical treatment reduces the operative blood loss at hysterectomy, and it seems very likely that the decrease in vascularity may play an important role.

Blood Loss, Surgical↗
PubMed1988

[Treatment of prostatic cancer with intranasal administration of LHRH analog, Buserelin (Hoe 766) study of the optimum dosage of intranasal application].

Patients with pathologically defined prostatic carcinoma (114 cases in 23 institutes) were subcutaneously administered 500 micrograms of Buserelin (Hoe 766) 3 times a day for 7 consecutive days, then randomized to intranasally administered 600 or 900 micrograms/day of Buserelin as maintenance treatment. We examined the clinical efficacy, safety and endocrinological effects of the drug by the intranasal dosage. Size of prostate decreased more than 25% in 21 cases (total 47 cases; measured at the start and 3 months treatment by ultrasonography. Complete response and partial response were observed in 13 cases (16.1%) by NPCP's criteria at 3 months Buserelin treatment. Grobal Improvement Rating (GIR) were respectively 64.3% (600 micrograms group) and 68.0% (900 micrograms group). Grobal Utility Rating (GUR) were respectively 85.7% (600 micrograms group) and 82.0% (900 micrograms group). No significance was observed in these two groups. Adverse reactions were observed in 21 cases (18.9%). Except in 1 case, they were slight and the Buserelin treatment could be continued. Objectively Safety Rating (OSR) was 92.8%. Five cases were treated for more than 2 years with Buserelin and these cases were well controlled. Buserelin was considered as an effective and safe drug to treat prostatic carcinoma.

Administration, Intranasal↗
PubMed1988

[The beneficial effects of short-term administration of a LHRH agonist (buserelin) in in vitro fertilization].

We have assessed the beneficial effects of administering a short course of an agonist of LHRH (Buserelin) in vitro fertilisation. 274 cycles were treated with CC-HMG, 159 were treated with HMG alone and 253 by Buserelin-HMG. These were compared retrospectively. The use of a short course of Buserelin lowered significantly the rate of failed treated cycles (7% instead of 19% when it was used with CC-HMG and 27% when used with HMG). This made it possible to administer hCG in all cases in the programme (100% as against 69% and 89% respectively for CC-HMG and HMG without Buserelin), and increase significantly the number of oocytes that could be recovered and the number of embryos available for transfer. The overall number of pregnancies per cycle treated is significantly raised when Buserelin is used with HMG (20.4% as against 13.5% for CC-HMG and HMG). The number of pregnancies that progressed, on the other hand, was similar when the cycle was stimulated with HMG alone (10.6%) or with Buserelin-HMG (10.6%).

Buserelin↗
PubMed1989

Buserelin in a superovulatory regimen for Holstein cows. I. Pituitary and ovarian hormone response in an experimental herd.

Two experiments were conducted with frequent blood sampling in standard superovulatory regimens using follicle stimulating hormone (FSH) and prostaglandin F(2) alpha (PGF) to study the effects of the gonadotropin releasing hormone analog, Buserelin, on changes in FSH, luteinizing hormone (LH), progesterone (P(4)) and estradiol (E(2)). In Experiment I, Buserelin (20 mug) was administered to a total of 28 dry Holsteins. One group was treated with Buserelin 36 and 60 h after PGF administration, a second group was treated 60 h after PGF, and a third group served as the controls. In Experiment II, 30 dry Holsteins received Buserelin (10 mug). One group was treated 48 h after PGF, a second group at 54 h after PGF, a third group 24 h after estrus was first observed and a fourth group was a control. The general pattern of a decrease in P(4) following PGF, an increase in E(2), the onset of estrus, an LH peak, and finally, an increase in P(4) in superovulated cows was observed. Buserelin consistently produced a sharp LH peak at 36 h when given 36 h after PGF. At later intervals, it produced either a major or minor peak depending upon whether a spontaneous LH peak had already occurred. There was too much individual cow variation in the interval from PGF to a spontaneous LH peak to consistently induce a uniform LH peak, except when Buserelin was given 36 h after PGF, which may be early for normal oocyte maturation. There was no treatment effect on FSH, and embryo recovery rate was unaffected by treatment (P>0.05).

Journal Article↗
PubMed1996

The effect of the gonadotrophin-releasing hormone analog, buserelin, administered in diestrus on pregnancy rates and pregnancy failure in mares.

Two trials involving 578 mares were performed to investigate the effect of a single intramuscular treatment of 40 microg buserelin, an analog of gonadotrophin releasing hormone, on pregnancy rate in mares. All mares were bred by natural mating and were allocated into pairs One mare in each pair was injected with buserelin either on Day 10 or 11 (Trial 1) or on Days 8 to 10 (Trial 2) after ovulation. Pregnancy status of mares was determined by transrectal ultrasonographic examination on Day 14 or 15 after the day of ovulation and was repeated between Days 28 and 30 of pregnancy. In Trial 1, buserelin treatment increased the pregnancy rate at Days 14 and 15 (72.5 vs 66.6%, P < 0.01). At the second pregnancy examination, pregnancy losses were lower in the treated group of mares (4.1 vs 7.4%; P < 0.05). In Trial 2, buserelin also improved the pregnancy rate (57.2 vs 53 5%; P < 0.05) at Days 14 and 15 Pregnancy losses between the first and second examinations were lower in the treated group of mares (6.5 vs 12.0%; P < 0.05). Buserelin increased pregnancy rates after breeding at the first estrus in both trials. In addition, buserelin treatment increased the pregnancy maintenance rate at Days 28 to 30.

Journal Article↗
PubMed1987

Influence of experimental rhinitis on the gonadotropin response to intranasal administration of buserelin.

The influence of experimental rhinitis on the absorption of buserelin, measured as the serum luteinizing hormone (LH) response, has been investigated. A single dose of 200 micrograms buserelin was given to 24 healthy male volunteers after induction of experimental rhinitis with histamine and after use of a saline spray (placebo control). Except on one occasion, when the pump-spray apparently was incorrectly operated, serum LH concentration rose after buserelin. There was no difference in the LH response between histamine-induced rhinitis and saline controls. It was concluded that intranasal application of buserelin represents a reliable mode of application and that modification of the administration route or a change in the dosage schedule during naturally-occurring nasal inflammations, such as the common cold and allergic rhinitis, is unnecessary in patients undergoing chronic treatment with intranasal buserelin, e.g. for prostatic cancer, endometriosis, precocious puberty, and contraception.

Absorption↗
PubMed1993

Effects of the luteinizing-hormone-releasing hormone (LHRH) antagonist ramorelix (hoe013) and the LHRH agonist buserelin on dimethylbenz[]anthracene-induced mammary carcinoma: studies with slow-release formulations.

Luteinizing-hormone-releasing hormone (LHRH) agonists and antagonists are antigonadotropic agents for reversible ovarian/testicular suppression in gynaecology and in oncology. Pituitary inhibition and suppression of the gonadal steroids can be maintained with continuous release rates from biodegradable implants or microparticles. The effects of curative and preventive treatment with slow-release formulations of the LHRH agonist buserelin (implants and microparticles) and the LHRH antagonist ramorelix (hoe013) (microparticles) on dimethylbenz[a]anthracene(DMBA)-induced mammary tumours in rats and the pharmacokinetics of these formulations are described. In addition, direct effects of the LHRH antagonist ramorelix on tumour growth were studied. The release rates of the implants (polylactide-glycolide 75:25) and the microparticles (polylactide-glycolide 50:50) were calculated from urinary excretion of the peptides. The curative treatment started at the time of full tumour development (76 days after DMBA induction). A single buserelin implant injection (3.3 mg peptide) resulted in a dramatic tumour regression within 14 days, which was comparable to ovariectomy. It prevented tumour progression for 120 days. Previous studies in rats have shown that ramorelix microparticles (3.6 mg peptide) have a shorter duration of action (about 14 days) in suppression of gonadal function when compared to buserelin microparticles (3.6 mg peptide), where the suppression lasted for about 35 days. As expected, a single injection of ramorelix microparticles (3.6 mg peptide) inhibited tumour progression for only 14 days. This short action is due to a different release profile of the ramorelix microparticles and the different specific activities of peptides incorporated. In the preventive experiments animals were treated 17 days after DMBA induction before tumour development. Treatment with buserelin implants (3.3 mg peptide) every 56 days or with buserelin microparticles (3.6 mg peptide) every 28 days and the treatment with ramorelix microparticles (1.8 mg peptide) every 7 days prevented the development of tumours. Six weeks after the last injection of ramorelix microparticles a strong tumour progression was seen. There was a clear correlation between peptide release and tumour inhibition. The implants and the microparticles were well tolerated, no tissue reaction or side-effects of ramorelix were seen. Treatment of ovariectomized oestradiol-substituted DMBA-treated rats resulted in a marginal (not significant) inhibition in tumour development. LHRH antagonists in slow-release formulations (microparticles or implants) represent a new approach in treatment of hormone-dependent tumours because of the immediate onset of gonadal function and the increased drug efficacy due to the controlled release from biodegradable microparticles.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1993

The behavior of epididymis, processus vaginalis and testicular descent in cryptorchid boys treated with buserelin.

This randomized double-blind, placebo-controlled study was initiated to analyze the behavior of epididymis, processus vaginalis and testicular descent in cryptorchid boys treated with a low dose (20 micrograms) of a luteinizing hormone-releasing hormone analogue (Buserelin), administered daily, as a nasal spray, for a short period (28 days). Fifty-nine true cryptorchid boys were randomly assigned to 3 groups: buserelin treatment [22], surgical treatment [18] or placebo control group [19]. The 3 groups of patients were similar before treatment in regard to testicular position, chronological and bone age, height and weight, luteinizing hormone, follicle-stimulating hormone, testosterone, penile size and the volume of the contralateral descended testis. None of the patients had retractile testes. Buserelin significantly induced testicular descent compared to the boys treated with a placebo (P < 0.01). A normal epididymis was found more often in boys with successful descent (P < 0.003). A closed processus vaginalis was also more frequently observed in the group treated with buserelin than in surgically treated one (P < 0.05). In conclusion, buserelin was capable of inducing testicular descent besides provoking further development of the epididymis and closing the processus vaginalis.

Administration, Intranasal↗
PubMed1989

Buserelin versus danazol in the treatment of endometriosis-associated infertility.

A total of 62 infertile women with a laparoscopic diagnosis of endometriosis were allocated randomly to two treatment groups, one of which (32 patients) received oral danazol 600 micrograms/day and the other (30 patients) received intranasal buserelin 1200 micrograms/day for 6 months. Suppression of serum levels of estradiol was greater with the gonadotropin-releasing hormone agonist treatment. Pain symptoms improved markedly during treatment in both groups. At the end of treatment a repeat laparoscopy was performed only in the patients who agreed to it (12 in the buserelin group and 13 in the danazol group), and it did not reveal significant differences in the effects of the two treatments on the endometriotic implants. All of the patients were followed up for at least 12 months, during which pregnancy was attempted. At 18 months the cumulative pregnancy rate was 48% in the patients treated with buserelin and 43% in those treated with danazol. Pain recurrence was observed in about half of the patients in each group 1 year after treatment suspension. The side effects were more frequent and more severe in the danazol-treated patients, whereas those given buserelin generally reported only symptoms of hypoestrogenism. The results of this study suggests that buserelin is at least as effective as danazol in the treatment of endometriosis when the outcome is considered in terms of restored fertility, and its side effects are less severe.

Adult↗
PubMed1992

Buserelin acetate versus expectant management in the treatment of infertility associated with minimal or mild endometriosis: a randomized clinical trial.

OBJECTIVE: We performed a randomized clinical trial to evaluate the efficacy of intranasal 400 micrograms buserelin three times daily for 6 months versus expectant management in the treatment of infertile women with pelvic endometriosis stage I or II of the revised American Fertility Society classification. STUDY DESIGN: Seventy-one consecutive patients (mean age 32 years) were studied at the First Department of Obstetrics and Gynecology, University of Milan, and the Department of Obstetrics and Gynecology, Ospedali Riuniti, Bergamo, between February 1988 and June 1989. Thirty-five women were randomly allocated to buserelin treatment and 36 to expectant management. The baseline distribution of subjects for age, disease stage, and reproductive history was similar in the two groups. All patients were followed regularly; median follow-up was 17 months in the buserelin group and 18 months in the women given expectant management. If pregnancy did not occur within 12 months of randomization, cycles were monitored by ultrasonography and hormone measurements, and when abnormalities were detected clomiphene citrate and human chorionic gonadotropin were administered. RESULTS: A total of 17 pregnancies were observed both in the buserelin-treated patients and in the expectant management group. The 1- and 2-year actuarial overall pregnancy rates were similar in the two groups, 30% and 61% in the former and 37% and 61% in the latter group, respectively. Spontaneous abortion occurred in five of the 17 pregnancies in the women treated with buserelin and in one of the 17 in those managed expectantly; this difference was, however, not statistically significant (chi 1(2) adjusted for disease stage and use of clomiphene citrate and human chorionic gonadotropin treatment = 3.01, p = 0.08). No fetal death or stillbirth was observed. CONCLUSIONS: Our findings suggest that treatment with gonadotropin-releasing hormone agonists is unlikely to have a marked influence on the reproductive outcome of infertile women with minimal or mild endometriosis.

Adult↗
PubMed1984

A comparison of the luteinizing hormone-releasing activities of synthetic chicken luteinizing hormone-releasing hormone (LH-RH), synthetic porcine LH-RH, and buserelin, an LH-RH analogue, in the domestic fowl.

The luteinizing hormone-releasing activities of synthetic chicken luteinizing hormone-releasing hormone (chLH-RH), synthetic porcine LH-RH (pLH-RH), and an analogue of LH-RH (buserelin, D-Ser-(But)6-des-Gly10-LH-RH ethylamide) were compared in the domestic fowl. In adult cockerels, intravenous injections of 0.5 or 1 microgram chLH-RH/kg released the same amount of LH as the same doses of pLH-RH; subcutaneous injections of 0.5 or 1 microgram buserelin/kg were about twice as effective as the same doses of pLH-RH. In laying hens, injections of 1, 10, 20, and 50 micrograms buserelin induced more sustained releases of LH than the corresponding doses of pLH-RH. Daily injections of 1 or 10 micrograms buserelin/bird or of 10 micrograms pLH-RH/bird for 12 days synchronized the timing of most ovipositions showing that the injections of releasing hormone could induce preovulatory surges of LH. In contrast with mammals, daily injections of buserelin in laying hens did not reduce pituitary responsiveness to the analogue. It is concluded that the structural difference between mammalian and chicken LH-RH does not affect their LH-releasing activities in the domestic fowl. Although the LH-releasing activity of buserelin in the hen is greater than that of pLH-RH, the difference in activity is not as great as that observed in most mammals. This view is strengthened by the finding that chronic treatment with buserelin, which exerts an antagonistic effect on ovulation in mammals, does not do so in the domestic hen.

Animals↗
PubMed1984

Modulation of cyclic AMP formation and progesterone secretion by human chorionic gonadotropin, epinephrine, buserelin and prostaglandins in normal or human chorionic gonadotropin desensitized rat immature luteal cells in monolayer culture.

It is now well recognized that hCG-induced luteolysis is associated with hCG-induced desensitization, but the physiological significance of luteal cell GnRH, PGS and beta-receptors is still undefined. Therefore, we intend in this study to observe the effects of prostaglandin F2 alpha and prostaglandin E2 and the interactions between epinephrine, a potent LHRH agonist [(D-Ser-(TBu)6, des-Gly-NH2(10)) LHRH ethylamide: Buserelin] and hCG in normal and in vitro hCG-desensitized rat immature luteal cells in monolayer culture, on basal, hCG or cholera toxin stimulated intracellular and extracellular cyclic AMP and progesterone secretion. The present report shows that incubation of immature rat luteal cells in monolayer culture with Buserelin, led to 25-50% inhibition of the epinephrine--as well as PGE2--induced cyclic AMP and progesterone responses. The LHRH agonist can also reverse the stimulatory effects of cholera toxin in the presence of hCG and led with PGF2 alpha, to additive inhibitory effects on extracellular cyclic AMP accumulation induced by cholera toxin. Both Buserelin and PGF2 alpha can reverse the hCG-induced cyclic AMP and progesterone release but no effect could be observed when the incubation was carried out with either substance in the absence of hCG. Prostaglandin E2, in acute conditions of incubation, seems to share agonist properties with hCG when both were incubated with luteal cells. Buserelin reversed the stimulatory effects of PGE2, hCG, epinephrine, and cholera toxin on cyclic AMP and progesterone responses to these substances. These results suggest that Buserelin and PGF2 alpha have luteolytic-like effects and that there may be a complementary action for the two substances. Preincubation of rat luteal cells in monolayer culture with 1 nM hCG for a 24 h period led to the inhibition of cyclic AMP and progesterone responses after a subsequent exposure to hCG and epinephrine. Luteal cells were no longer responsive to hCG while the presence of epinephrine in hCG-desensitized cells led to a 40% stimulation of cAMP and progesterone production. These observations suggest that there occurred a partial alteration of the N component activity of the adenylyl cyclase system.

Animals↗
PubMed1984

Modulation of cyclic AMP formation and progesterone secretion by human chorionic gonadotropin, epinephrine, buserelin and prostaglandins in normal or human chorionic gonadotropin desensitized rat immature luteal cells in monolayer culture.

It is now well recognized that hCG-induced luteolysis is associated with hCG-induced desensitization, but the physiological significance of luteal cell GnRH, PGs and beta-receptors is still undefined. Therefore, we intend in this study to observe the effects of prostaglandin F2 alpha and prostaglandin E2 and the interactions between epinephrine, a potent LHRH agonist [(D-Ser-(TBu)6, des-Gly-NH10(2) LHRH ethylamide: Buserelin] and hCG in normal and in vitro hCG-desensitized rat immature luteal cells in monolayer culture, on basal, hCG or cholera toxin stimulated intracellular and extracellular cAMP and progesterone secretion. The present report shows that incubation of immature rat luteal cells in monolayer culture with Buserelin, led to 25-50% inhibition of the epinephrine-as well as PGE2-induced cAMP and progesterone responses. The LHRH agonist can also reverse the stimulatory effects of cholera toxin in the presence of hCG and led with PGF2 alpha, to additive inhibitory effects on extracellular cAMP accumulation induced by cholera toxin. Both Buserelin and PGF2 alpha can reverse the hCG-induced cAMP and progesterone release but no effect could be observed when the incubation was carried out with either substance in the absence of hCG. Prostaglandin E2, in acute conditions of incubation, seems to share agonist properties with hCG when both were incubated with luteal cells. Buserelin reversed the stimulatory effects of PGE2, hCG, epinephrine and cholera toxin on cAMP and progesterone responses to these substances. These results suggest that Buserelin and PGF2 alpha have luteolytic-like effects and that there may be a complementary action for the two substances. Preincubation of rat luteal cells in monolayer culture with 1 nM hCG for a 24 h period led to the inhibition of cAMP and progesterone responses after a subsequent exposure to hCG and epinephrine. Luteal cells were no longer responsive to hCG while the presence of epinephrine in hCG-desensitized cells led to a 40% stimulation of cAMP and progesterone production. These observations suggest that occurred a partial alteration of the N component activity of the adenylyl cyclase system.

Animals↗
PubMed1989

Buserelin in the treatment of prostatic cancer.

Buserelin is a synthetic gonadotropin-releasing hormone (GnRH) analog which is more potent than natural GnRH. Prolonged administration of the drug produces, after a short phase of stimulation, a selective and durable inhibition of secretion of pituitary gonadotropins, resulting in medical castration. In pilot and controlled studies buserelin shows a response rate that is similar to that of diethylstilbestrol or orchiectomy in the palliative treatment of advanced prostatic cancer, but larger and better designed studies are needed before reaching definitive conclusions about the duration of response and survival. The most common adverse effects of buserelin are loss of libido and/or impotence, hot flushes and possible flare-up of prostatic carcinoma symptoms in the first week of therapy. The combination of buserelin with an antiandrogen could avoid the flare syndrome; whether the combination has advantages compared to administration of buserelin alone requires confirmation from the large randomized studies still in progress.

Androgen Antagonists↗
PubMed2006

Duration of testosterone suppression after a 9.45 mg implant of the GnRH-analogue buserelin in patients with localised carcinoma of the prostate a 12-month follow-up study.

OBJECTIVES: (1) To determine the duration of androgen deprivation after a single buserelin implant 9.45 mg in the neoadjuvant setting in combination with curative radiation therapy of carcinoma of the prostate, and (2) to evaluate the time to recovery of gonadal function, and the incidence and duration of hypogonadal symptoms. METHODS: We prospectively evaluated 21 men with carcinoma of the prostate who received one implant of 9.45 mg buserelin subcutaneously. Release of buserelin, changes in serum testosterone concentration, hot flushing and sexual function over a 12-month study period were recorded. RESULTS: Testosterone was suppressed below the castration limit (0.58 ng/ml=2 nmol/l) for 224 days (range, 139-309). The mean time to first return of testosterone above the castration limit was 246 days (range, 168-344); 50% of pre-treatment value was reached after 285 days (range, 218-370). The prevalence of hot flushing was 19 of 21 patients (90%) at 12 weeks. At the end of the study period, serum testosterone had reached 80% (range, 33%-166%) of pre-treatment concentration, sexual interest was present in 52%, erection was possible in 60%, and hot flushing remained in 24%. CONCLUSION: A single injection of 3-month buserelin implant 9.45 mg suppresses serum testosterone below the castration limit for at least 6 months. Testosterone secretion recovers by 8-12 months. Hypogonadal symptoms decreased with the restoration of serum testosterone secretion. These data are clinically relevant regarding the dose schedule for buserelin and the patient information provided.

Aged↗