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At least 19 recordsLinked to original sources
PubMed1987

LRH agonist buserelin as a post-partum contraceptive: lack of biological activity of buserelin in breast milk.

To evaluate the possibility of using the LRH agonist buserelin as a contraceptive for lactating women we have investigated the passage of buserelin into breast milk and explored possible biological activity in the infant. Eleven mothers received 600 micrograms buserelin by nasal spray. Buserelin was measured by radioimmunoassay in the breast milk of these mothers, and values ranged from undetectable levels (less than 15 pg/ml) to 8800 pg/ml. The maximum amount of buserelin that an infant could ingest during an average feed would be 1-2 micrograms. In adult men ingestion of 600 micrograms buserelin dissolved in cows milk was without biological effect upon both serum and urinary levels of luteinizing hormone. There was no change in the levels of LH found in the urine of infants fed by women who had received 600 micrograms buserelin by nasal spray. We conclude that the small amount of buserelin passing into the breast milk of these volunteers was without biological activity when ingested by the infant.

Administration, Intranasal↗
PubMed1987

Metastatic cancer of the prostate managed with buserelin versus buserelin plus cyproterone acetate.

We recruited 71 previously untreated patients with metastatic prostatic carcinoma to 2 separate consecutive prospective phase 2 studies done by the same group of investigators according to the same protocols in which only the treatment regimens differed. Of the patients 58 were treated with the luteinizing hormone-releasing hormone analogue buserelin alone (0.4 mg. 3 times daily intranasally) and 13 were treated with buserelin combined with cyproterone acetate, a potent antiandrogen (50 mg. 3 times daily orally). The objective of the study was to investigate the efficacy, safety and tolerability of the medication used during at least 12 months by studying adequate endocrine parameters, the rate and duration of response, as well as the rate of progression and possible side effects. All endocrine parameters were studied in 1 laboratory. Modified response criteria of the National Prostatic Cancer Project were used. The endocrine studies showed an effective suppression of plasma testosterone to castration levels by buserelin after an initial increase during the first 2 weeks. Luteinizing hormone and follicle-stimulating hormones were lowered significantly and could not be re-stimulated by the intravenous application of luteinizing hormone-releasing hormone. There was no correlation of plasma testosterone with response and progression. However, a significant correlation existed between higher basal cortisol levels at entry, and after 3 and 6 months, and progression. Response is reported for all patients at the 12-month interval and did not seem to differ among treatment groups. The rate of progression after all patients had been treated for 1 year was 37.9 per cent in the buserelin group and 41 per cent in the buserelin plus cyproterone acetate group. Three early deaths occurred in the buserelin group. Except for impotence, only mild side effects were noted. Our study shows that treatment of metastatic prostatic cancer by means of the luteinizing-hormone-releasing hormone analogue buserelin is safe and effective. The results obtained are compatible with those obtained by castration. In our study a superiority of total androgen withdrawal over testicular suppression alone could not be shown.

Buserelin↗
PubMed1989

Administration of nasal Buserelin as compared with subcutaneous Buserelin implant for endometriosis.

One hundred infertile patients with laparoscopically confirmed ovarian endometriosis were treated with either intranasal (IN) Buserelin (Hoechst, AG, Frankfurt am Main, West Germany) (300 micrograms three times a day) or subcutaneous (SC) Buserelin implant (6.6 mg Buserelin). Serum estradiol was suppressed in the menopausal range in both groups, but the inhibition of the pituitary ovarian axis appeared more profound and consistent in the SC group than in the IN group. Laparoscopic findings proved that the SC Buserelin emerged superior to the IN Buserelin. Indeed, the score of endometriotic lesions and the ovarian cyst diameter were more reduced in the SC group than in the IN group. Moreover, the histologic study showed a lower incidence of active endometriosis and a lower mitotic index of ovarian endometrial epithelium in the SC group than in the IN group. In conclusion, the release of a gonadotropin-releasing hormone agonist by a biodegradable implant achieved better efficacy in reducing endometriotic lesions than the IN mode of administration.

Administration, Intranasal↗
PubMed1996

Midluteal buserelin is superior to early follicular phase buserelin in combined gonadotropin-releasing hormone analog and gonadotropin stimulation in in vitro fertilization.

OBJECTIVE: To establish whether time to down-regulation and pregnancy and live birth rates were different when buserelin acetate was started in the midluteal phase or early follicular phase in IVF-ET patients. DESIGN: Prospective, controlled, randomized, parallel-group multicenter clinical study. SETTING: Women attending seven infertility clinics. PATIENTS: One hundred twenty-four women with tubal or unexplained infertility with normal menstruation and fertile partners. INTERVENTIONS: Intranasal buserelin acetate started in the midluteal or early follicular phase combined with standard hMG and hCG stimulation after achievement of down-regulation. Established IVF-ET methods. MAIN OUTCOME MEASURES: Duration of down-regulation; clinical pregnancy and live birth rates. RESULTS: Kaplan-Meier estimations of the duration of down-regulation were 15.5 days when buserelin acetate was started in the early follicular phase (127 cycles) and 14.6 days when it was started in the midluteal phase (96 cycles). This difference was statistically significant. The pregnancy rates per first treatment cycle, treatment cycle, oocyte retrieval, and ET were significantly higher when buserelin acetate was started in the midluteal phase. The live birth rates were also higher, but only significantly so for the rate per first treatment cycle. CONCLUSIONS: Clinical pregnancy and live birth rates are better when buserelin acetate is started in the midluteal phase rather than the early follicle phase before hMG and hCG stimulation in preparation for IVF-ET.

Administration, Intranasal↗
PubMed1996

The effect of Buserelin versus conventional antiandrogenic treatment in patients with T2-4NXM1 prostatic cancer. A prospective, randomized multicentre phase III trial. The "Danish Buserelin Study Group".

A prospective, randomized multicentre phase III trial was undertaken to compare the effectiveness and safety of Buserelin, a gonadotropin-releasing hormone analogue (GnRHa), with conventional antiandrogenic treatment in patients with painful metastases from T2-4NXM1 prostatic cancer. Seventy-two patients received Buserelin, 22 received estrogens and 46 were subjected to orchiectomy. The trial was completed one year after allocation of the patients. No significant differences as regards suppression of testosterone or survival were found in favour of one of the three treatment modalities. The performance index improved significantly both during the first months of treatment with Buserelin and following orchiectomy. No detectable improvement of performance index was seen during treatment with estrogens. Treatment with estrogens also failed to alleviate pain or general symptoms of cancer. Tolerability, safety and compliance of Buserelin was although administered intranasally clearly evidenced as palliation of advanced symptomatic cancer and the efficacy and sideeffects were fully comparable to those following orchiectomy.

Aged↗
PubMed1989

Serum concentration and urinary excretion of the luteinizing hormone-releasing hormone agonist buserelin in patients with endometriosis.

We studied the pharmacokinetics of iv and intranasally administered buserelin, a LHRH agonist peptide, in 14 women with endometriosis. Serum and urinary buserelin concentrations were determined by specific RIA (buserelin antiserum AS-639). Intact buserelin and the metabolites in urine were separated by reverse phase high performance liquid chromatography and measured by RIA. The mean serum buserelin concentrations were 101 +/- 33 (+/- SD) ng/mL 20 min and 1.12 +/- 0.12 ng/mL 360 min after its iv injection in 6 women, and the mean elimination half-life between 20 and 360 min was 51 min. In serum, intact buserelin was the main constituent (10 min, 90%; 120 min, 74%; 360 min, 52%), and the major metabolite was the buserelin-(5-9) pentapeptide (10 min, 0.6%; 120 min, 19%; 360 min, 12%). In the urine collected 0-1 h after buserelin administration, intact buserelin was 66% and the 5-9 pentapeptide was 28% of the total excretion. In the urine collected between 6-24 h after buserelin administration, intact buserelin accounted for 67% and the 5-9 pentapeptide for 32% of the total excretion. The urinary buserelin concentration was 1345 +/- 156 micrograms/g creatinine 1 h and 25 +/- 5 micrograms/g creatinine 6-24 h after buserelin administration. Serum LH, FSH, and estradiol concentrations increased acutely up to 10-fold above basal values; the mean peak LH, FSH, and estradiol values occurred at 180-240 min, 240 min, and 24 h, respectively. In therapeutic studies with buserelin nasal spray in 5 women, serum concentrations of 0.9-1.4 ng/mL were found 15 min after a single dose of 300 micrograms, intranasally, and the urinary excretion was 2.52-3.68 micrograms/24 h during daily administration of 3 doses of 300 micrograms at intervals of 8 h. These results confirm that buserelin is slowly inactivated and remains available to pituitary receptors for a prolonged period after its iv or intranasal administration.

Administration, Intranasal↗
PubMed1986

The prolonged action of the LHRH agonist buserelin (HOE 766) may be due to prolonged binding to the LHRH receptor.

Hemi-pituitary glands of ovariectomized rats were superfused for 4 h with either LHRH or the analog buserelin (HOE 766) at several concentrations, and thereafter with medium only for another 1.5 h. In a further experiment glands were exposed for 2.5 h to LHRH or buserelin at a single concentration (5 ng/ml) and subsequently for another 2.5 h to either the same agonist (LHRH or buserelin) alone (5 ng/ml), the agonist plus an LHRH-antagonist (ORG 30093, 1000 ng/ml), the LHRH- antagonist alone, or medium alone. LHRH and buserelin stimulated gonadotropin release equally well. After cessation of this stimulation, the gonadotropin release by the buserelin-treated pituitary glands and the glands, treated with the highest dose of LHRH (1000 ng/ml), continued, while the release by the glands, treated with the lower doses of LHRH, declined. The LHRH-antagonist completely blocked the release of LH, stimulated by buserelin or LHRH, as well as the prolonged activation of the release, caused by buserelin pre-treatment. In a superfusion experiment with pituitary cell aggregates of 14-day-old intact female rats, buserelin stimulated the release of LH much more effectively than LHRH itself. Moreover, the release caused by buserelin declined more slowly after cessation of the stimulation. Finally, in a pituitary cell monolayer culture the Kd's of LHRH, buserelin and the antagonist were determined as 4.7 X 10(-9) M, 2.4 X 10(-10) M and 4.6 X 10(-9) respectively. It was concluded that the estimates of the potencies of LHRH and buserelin depend on the choice of the test-system. It is suggested that the long duration of action of buserelin is at least partly due to prolonged binding to the LHRH-receptor.

Animals↗
PubMed1999

The mechanisms of antitumor effects of luteinizing hormone-releasing hormone agonist (buserelin) in 7, 12-dimethylbenz(a)anthracene-induced rat mammary cancer.

We evaluated the mechanism of antitumor effects of buserelin, which is one of LH-RH agonists, on a hormone dependent breast cancer model, using 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary cancer. Rats developing solid mammary tumors within 5-7 weeks following the DMBA administration were divided into groups weekly, and treated without delay. The tumor bearing rats were randomized into five groups with regard to tumor size or average weight (15 rats per group). Each group received one of the following treatments during 4 weeks: a) no treatment (NT); b) ovariectomy (Ovx); c) buserelin; d) Ovx and 17beta-estradiol (E2) (Ovx+E2); e) Ovx+E2+buserelin. Tumor regression immediately began at one week after both buserelin treatment and ovariectomy. A significant reduction of tumor size was observed in both buserelin-treated rats and Ovx rats compared with NT rats (p<0.01). No significant difference of tumor size was observed between buserelin-treated rats and ovariectomized rats. No reduction of tumor size was observed in Ovx+E2 rats and Ovx+E2+buserelin rats. Although the mean uterine wet weight of the buserelin group was significantly higher than that of the Ovx group, it was significantly lower than that of the NT group. The mean uterine wet weight of the NT group, the Ovx+E2 group and the Ovx+E2+buserelin group was similar and was significantly higher than that of the Ovx group. Buserelin did not inhibit exogenous estrogen-dependent tumor growth in DMBA-induced rat mammary cancers. These results suggest that buserelin has no direct effects on DMBA-induced rat mammary cancers, and the main mechanism of action of buserelin for tumor-reduction is due to ovarian estrogen deficiency.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1986

Pharmacokinetic characteristics of the gonadotropin-releasing hormone analog D-Ser(TBU)-6EA-10luteinizing hormone-releasing hormone (buserelin) after subcutaneous and intranasal administration in children with central precocious puberty.

A double antibody RIA was developed for the measurement of the long-acting GnRH agonist D-Ser(TBU)6EA10GnRH (buserelin). The antibody, raised in rabbits against a buserelin-hemocyanin conjugate, reacted with the intact molecule and also molecular fragments containing the C6-9 tetrapeptide sequence and permitted the measurement of buserelin activity in serum and urine. Natural GnRH, LH, and FSH did not cross-react in this assay system. The assay was applied to samples obtained from children receiving buserelin for the management of central precocious puberty either by once daily injection of 30 micrograms/kg or by nasal spray (in; 200 micrograms every 8 h). Urine and serum samples, chromatographed on Sephadex G-25, contained immunoreactive material corresponding closely in molecular size to [125I]buserelin. In unextracted serum samples taken at intervals after sc therapy in 11 girls, the peak immunoreactive buserelin levels of 52.2 +/- 14.8 ng/ml (mean +/- SEM) occurred at 30 min. The half-time of elimination was 74.9 +/- 36.9 min. Approximately 30% of the dose was detected in urine collected for 3 h after injection. Similar data were obtained in 3 normal adults given 10 micrograms/kg buserelin, iv. By contrast, after the administration of 200 micrograms buserelin by metered nasal spray, the mean peak serum concentration in 10 girls was 100-fold less (0.65 +/- 0.14 ng/ml), although the halftime of elimination was almost identical. Only 0.73% of the nasal dose was excreted by 3 h. Calculated relative bioavailability data indicated maximal nasal absorption of 6%. However, absorption after nasal administration varied greatly, and in 2 children, serum and urinary concentrations of buserelin after supervised administration were negligible. We conclude that in buserelin therapy, in the dose used in this study, does not represent optimal treatment for the initial management of patients with precocious puberty. The success of in therapy in sustaining initial effects of buserelin given by sc administration presumably reflects changes in receptor sensitivity induced by sc treatment.

Administration, Intranasal↗
PubMed1993

Norethindrone acetate only partially protects the skeleton of rats treated with the LHRH agonist buserelin from oestrogen-deficiency osteopaenia.

In women with endometriosis there is concern that therapeutic use of LH-releasing hormone (LHRH) analogues, to lower ovarian oestrogen production and control endometrial hyperplasia, leads to unwanted oestrogen-deficiency bone loss. We have developed an animal model of this LHRH-mediated oestrogen-deficiency bone loss in the rat, using buserelin. The aim was to use this model to determine whether the progestogen, norethindrone acetate, could counter oestrogen-deficiency bone loss associated with prolonged treatment with the LHRH agonist buserelin. Four groups of animals which had their bones labelled with 45Ca were studied for 4 weeks: group A, control; group B, buserelin treated; group C, norethindrone acetate treated; group D, norethindrone acetate+buserelin treated. Buserelin was given daily (19.2 pmol/kg body wt); norethindrone was given orally three times/week (1.47 mumol/kg body wt). Bone resorption was monitored by measuring the urinary excretion of hydroxyproline and 45Ca and bone 45Ca content. Buserelin-treated rats developed similarly depressed plasma oestradiol-17 beta values in the presence and absence of progestogen, and both groups given buserelin had significantly smaller uteri than controls or rats given norethindrone without buserelin. However, norethindrone did not prevent buserelin-mediated increases in bone resorption. At the end of the study total body calcium values (mean +/- S.D.) in the four groups were (mg) respectively; 2594 +/- 123; 2260 +/- 92 (P < 0.001 compared with controls); 2616 +/- 221; 2415 +/- 130 (P < 0.02 compared with controls). Rats given norethindrone and buserelin in combination had higher values (P < 0.02) than animals given buserelin alone, but significantly less total body calcium than controls (P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Buserelin. A review of its pharmacodynamic and pharmacokinetic properties, and clinical profile.

The gonadotrophin releasing hormone (GnRH) [luteinising hormone-releasing hormone (LHRH); gonadorelin] agonist buserelin is a promising new agent in the treatment of a variety of disorders in gynaecology and andrology, paediatrics and oncology. While a single dose of buserelin stimulates the release of pituitary gonadotrophins, multiple doses produce reversible pituitary desensitisation, and this specific blockade of gonadotrophin support to the gonads provides the basis for the drug's efficacy in conditions dependent on sex hormone secretion. Thus, buserelin provides comparable efficacy to orchidectomy or high dose estrogens in the treatment of hormone-sensitive prostate cancer and exhibits a lower incidence of adverse effects. During the early phase of treatment it may be particularly useful in combination with antiandrogens. Buserelin also appears promising in hormone-sensitive premenopausal breast cancer. Extensive studies have proven the value of buserelin in endometriosis, where it produces a transient remission with gradual recurrence of the disease on cessation of treatment. Surgical intervention is necessary in severe disease after buserelin-induced involution of the lesions. In patients with uterine leiomyoma, preliminary data suggest that buserelin may be beneficial in rendering surgery more conservative by reducing fibroid size, although it appears unlikely to preclude surgical intervention. The use of buserelin to induce a state of reversible hypogonadotrophism before administration of exogenous gonadotrophins is a promising strategy in the treatment of infertility associated with polycystic ovary syndrome and other conditions of infertility with underlying ovarian dysfunction; such a strategy also clearly enhances the efficiency of in vitro fertilisation programmes. Initial studies suggest its potential usefulness as a female contraceptive when administered intermittently in conjunction with a progestogen. Buserelin represents a first-line treatment of central precocious puberty. In endometriosis the adverse effect profile of buserelin is generally favourable, with hypoestrogenic effects such as hot flushes and vaginal dryness, and decreased libido, predominating. There is no apparent detrimental effect on lipid metabolism. The potential for adverse hypoestrogenic effects on bone mineral content with long term administration remains to be clarified. Thus, the GnRH agonist buserelin represents an advance in the treatment of a variety of gynaecological and andrological as well as paediatric and oncological conditions, infertility and other sex-hormone dependent conditions, with a low incidence of adverse treatment effects.

Animals↗
PubMed1994

Effect of administration and subsequent cessation of buserelin on cancellous bone of female rats.

Although hormone replacement therapy is effective in preventing postmenopausal bone loss, it fails to cause a return of bone mass to normal in patients with established osteoporosis. Similarly, in the ovariectomized rat, estrogen administration protects the skeleton from bone loss but fails to reverse this once it has occurred. However, physiologically produced sex steroids may, in contrast to conventional methods of sex steroid administration, be capable of restoring bone mass in osteopenic states. To investigate this question, we analyzed the effect of treatment with the LHRH agonist buserelin for varying durations, and subsequent cessation thereof, on histomorphometric indices of rat cancellous bone. Female rats 13 weeks old were given daily SC injections of vehicle or buserelin as follows: vehicle days 1-90; vehicle days 1-150; vehicle days 1-60, buserelin days 61-90; vehicle days 1-60, buserelin days 61-90, vehicle days 91-150; vehicle days 1-30, buserelin days 31-90; vehicle days 1-30, buserelin days 31-90, vehicle days 91-150; buserelin days 1-90; buserelin days 1-90, vehicle days 91-150. At the end of the treatment period, animals were killed, tibiae removed, and histomorphometric indices assessed at the secondary spongiosa of the proximal metaphysis. Analysis of vaginal smears confirmed that buserelin rapidly suppressed ovulation, which quickly returned once treatment was stopped. We found that administration of buserelin for 30, 60, or 90 days reduced cancellous bone volume because of a reduction in both the number and thickness of trabeculae.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2001

Use of buserelin to induce ovulation in the cyclic mare.

Inducing ovulation in a cyclic mare is often necessary. For this purpose, hCG has been used commonly, but the response can be reduced after successive administrations. The aims of this study were to test the effectiveness of buserelin in hastening ovulation in estrus mares, and its influence on fertility; and to investigate the effect of treatment on LH secretion. Five crossover trials were designed to compare the effect of two treatments: buserelin (40 microg in 4 doses i.v. at 12 h intervals) vs placebo (Experiments 1 and 2); buserelin 40 microg (in 4 doses i.v.) vs 20 microg (Experiment 3); buserelin (4 doses of 20 microg i.v.) vs hCG (1 dose of 2,500 IU i.v.) (Experiment 4); or buserelin (3 doses of 13.3 microg at 6 h interval) vs hCG (Experiment 5). In Experiment 2, blood samples were taken hourly until ovulation, for LH measurements. In Experiment 1, buserelin treatment significantly hastened ovulation. Reduction of the dose by half (Experiment 3) did not alter the effectiveness. In Experiments 4 and 5, buserelin was as effective as hCG in inducing ovulation between 24 and 48 h after initiation of treatment. Buserelin treatment induced a rise in LH concentration during the 48 h period of the experiment, and LH concentrations before ovulation were significantly higher in buserelin treated cycles than in placebo cycles. These experiments demonstrated the usefulness of two new protocols of administration of buserelin, as an alternative to hCG for induction of ovulation. One hypothesis explaining the mechanism of action is that the persistant rise in LH concentration could modify the ratio of biological/immunological LH, as it occurs physiologically, thereby hastening ovulation.

Animals↗
PubMed1993

17-Hydroxyprogesterone response to buserelin testing in the polycystic ovary syndrome.

OBJECTIVE: We determined the 17-hydroxyprogesterone (17-OH P) response to buserelin, a GnRH agonist, and its relation to ovarian volume in the patients with polycystic ovary syndrome (PCOS). DESIGN: We compared 17-OH P response to buserelin in a large group of patients with that in a control group of healthy women. We also investigated whether there is any relation between LH-induced 17-OH P production in response to buserelin and ovarian volume. PATIENTS: Ten normal women and 31 women with PCOS were included in the study. MEASUREMENT: Pelvic ultrasound examination by abdominal or vaginal transducer was performed. Serum basal levels of LH, FSH, free testosterone and 17-OH P were measured by radioimmunoassay. 17-OH P responses to both ACTH and buserelin were detected. Cortisol levels were measured before and after dexamethasone suppression. RESULTS: The subcutaneous administration of 1 mg buserelin produced an increase in serum 17-OH P, which peaked within 24 hours in all groups. The mean +/- SEM level of 17-OH P, 24 hours after buserelin stimulation in the women with PCOS (15.94 +/- 1.31 nmol/l) was significantly higher (P < 0.001) than in the control group (6.75 +/- 0.69 nmol/l). The women with PCOS had increases in 17-OH P levels exceeding 10.15 nmol/l 24 hours after buserelin testing. The increased 17-OH P responses to buserelin were unchanged by pretreatment with dexamethasone to suppress adrenal function. The 17-OH P response was significantly related to ovarian volume (r = 0.53, P < 0.01). CONCLUSIONS: Our findings suggest that the serum 17-OH P response to a 1-mg subcutaneous test dose of buserelin may be a diagnostic and practical test for PCOS. increased ovarian volume in PCOS may be responsible for the elevated 17-OH P response to buserelin, a GnRH agonist, at least in some patients.

17-alpha-Hydroxyprogesterone↗
PubMed1989

A new way to induce oestrogen-deficiency osteopaenia in the rat: comparison of the effects of surgical ovariectomy and administration of the LHRH agonist buserelin on bone resorption and composition.

Prolonged administration of LHRH agonist suppresses pituitary gonadotrophin secretion, thereby lowering blood oestrogen. This study was undertaken to compare the osteopaenic effects of bilateral ovariectomy and chronic administration of the LHRH agonist, buserelin, in the rat. Four groups of animals which had their skeletons labelled with 45Ca were studied for 4 weeks. Group 1 underwent a sham-ovariectomy, group 2 were surgically ovariectomized, group 3 were given buserelin by daily s.c. injection and group 4 were given a continuous infusion of buserelin by osmotic minipump. Plasma concentrations of oestradiol were measured weekly. Bone resorption was assessed by measuring the urinary excretion of 45Ca and hydroxyproline and determining bone 45Ca content. Ovariectomy and buserelin treatments lowered blood oestradiol, increased biochemical indices of bone resorption and decreased femur and total body calcium and 45Ca values. The degree of oesteopaenia elicited by ovariectomy and buserelin treatment was similar. Bone responses to s.c. buserelin and to continuous buserelin infusion were alike. We attribute evidence of increases in bone resorption and induction of osteopaenia with buserelin treatment to hypo-oestrogenism. We have shown for the first time by bone analysis that buserelin induces osteopaenia as effectively as bilateral ovariectomy. This appears to be the first demonstration in the rat that long-term administration of LHRH agonist influences bone. Administration of buserelin provides a new way of inducing oestrogen-deficiency osteopaenia in the rat without removing the ovaries.

Animals↗
PubMed1990

Buserelin-mediated osteoporosis: effects of restoring estrogen on bone resorption and whole body calcium content in the rat.

In the rat, prolonged administration of the luteinizing, hormone-releasing hormone agonist buserelin (25 micrograms/kg body wt/day s.c.) lowers blood estradiol, raises bone resorption, and induces osteopenia. The present study was undertaken to determine whether withdrawal of buserelin normalizes blood estradiol, slows bone resorption, and corrects buserelin-mediated osteopenia. Four groups of female rats with 45Ca-labeled bones were studied: group 1A received 0.2 ml saline s.c. daily for 4 weeks; group 2A received 0.2 ml buserelin s.c. daily for 4 weeks; group 1B received 0.2 ml saline s.c. daily for 8 weeks; group 2B received 0.2 ml buserelin s.c. daily for 4 weeks followed by 0.2 ml saline s.c. daily for 4 weeks. Bone resorption was monitored by measuring urinary 45Ca and hydroxyproline. The rats in groups 1A and 2A were killed after 4 weeks and those in groups 1B and 2B after 8 weeks. The mineral contents of the femoral bones and the whole skeletons were measured. Buserelin lowered blood estradiol, elevated urinary 45Ca and urinary hydroxyproline, and lowered femur and total body calcium and 45Ca in group 2A vs. 1A (P less than 0.05). By contrast all these measurements became similar in groups 2B and 1B. Thus, osteopenia generated by a 4-week period of buserelin-mediated hypo-estrogenism is reversible by withdrawing buserelin for 4 weeks. Consequently, buserelin administration and withdrawal may be used to study effects of inducing and reversing estrogen-deficiency bone loss in the rat.

Animals↗
PubMed2002

Comparison between buserelin and dexamethasone testing in the assessment of hirsutism.

Many hirsute women may present a form of functional ovarian hyperandrogenism (FOH), since they show an exaggerated 17-hydroxyprogesterone (17-OHP) response to GnRH agonists administration. As the failure of dexamethasone to reduce testosterone levels may be indicative of an ovarian source of androgen secretion, we evaluated the usefulness of dexamethasone suppression test, in comparison with buserelin challenge, in the assessment of hirsutism. Twenty-seven hirsute women (aged 15-42 yr) underwent ACTH and buserelin tests: 4 patients were heterozygotes for 21-OH deficiency and 8 patients were affected with FOH: 2 of the patients with hyperresponse to buserelin also had 21-hydroxylase deficiency. The results of the dexamethasone suppression test (2 mg/day for 7 days) were compared to those obtained after buserelin test. Basal T and delta4 levels (mean+/-SE) were higher than in controls (4.2+/-0.5 vs 2.2+/-0.2 nmol/l and 10.9+/-0.9 vs 5.9+/-0.6 nmol/l, p<0.02), while no differences were found in 17-OHP and DHEAS levels. A significant reduction (p<0.001) in T (1.8+/-0.4 nmol/l), delta4 (3.2+/-0.5 nmol/l) and DHEAS levels (2.4+/-0.3 micromol/l) was observed at the 3rd day of dexamethasone administration and no differences between sampling at 3rd, 5th and 7th day were found. Serum T was not suppressed in 6 cases, delta4 and DHEAS levels in 3 and 1 of them, respectively. Buserelin injection caused an excessive 17-OHP response in 8 patients, only 4 of them did not reduce T levels during dexamethasone. The sensitivity and specificity of the dexamethasone suppression test, with respect to the buserelin test, were 50% and 89%, respectively. In conclusion, 37% of hirsute patients had an abnormal responsiveness to buserelin and/or ACTH tests, indicating that hormonal investigations are mandatory. An ovarian origin of hirsutism was identified by buserelin test in 30% of patients and by dexamethasone in 22% of cases; only 4 of 8 patients showed concordant results to both tests. Therefore, buserelin challenge seems a more useful, cost-effective and less time consuming tool than dexamethasone administration in order to recognize the possible ovarian origin of hyperandrogenism.

Adolescent↗