Injection Of Gonadotropin-releasing Hormone Agonist Research Articles

Recovery of Spermatogenesis by High Dose Gonadotropin-Releasing Hormone Analogue Treatment in Rat Cryptorchid Testis after Orchiopexy

Cryptorchidism is an adverse condition of spermatogenesis in many mammals. Surgical cryptorchidism in rats lasting more than a few weeks is so detrimental that spermatogenesis cannot be completely recovered even after orchiopexy. We evaluated the efficacy of the high dose gonadotropin-releasing hormone (Gn-RH) agonist leuprorelin acetate on damaged spermatogenesis in rat cryptorchid testes. Male Fisher rats were divided into 2 groups of 6 each and bilateral cryptorchidism was artificially produced. Five weeks later all rats underwent bilateral orchiopexy. One group served as the control, while the other received Gn-RH agonist injections at orchiopexy and 4 weeks later. The animals were sacrificed 15 weeks after orchiopexy. The weight of the body, testis and epididymis was measured and the histology of spermatogenesis was examined. For statistical analysis the Student t test was applied. Testes in the Gn-RH group rats showed significant recovery of spermatogenesis up to complete spermatozoa formation, while those in control rats remained almost degenerated. The mean incidence of seminiferous tubules with recovered spermatogenesis plus or minus standard deviation was significantly higher in the Gn-RH than in the control group (87.8% +/- 6.0% versus 12.5% +/- 7.7%, p <0.001). Administering the high dose Gn-RH agonist leuprorelin acetate after orchiopexy greatly enhanced the recovery of spermatogenesis in rats. This finding is in accordance with other recent reports that treatment with Gn-RH analogues promotes the regeneration of once damaged spermatogenesis. On the other hand, these findings may cause one to question supplementation therapy now used in regular practice to boys with cryptorchidism.

Control of ovulation with a GnRH agonist after superstimulation of follicular growth in buffalo: fertilization and embryo recovery

The potential to use a GnRH agonist bioimplant and injection of exogenous LH to control the time of ovulation in a multiple ovulation and embryo transfer (MOET) protocol was examined in buffalo. Mixed-parity buffalo (Bubalus bubalis; 4–15-year-old; 529±13kg LW) were randomly assigned to one of five groups (n=6): Group 1, conventional MOET protocol; Group 2, conventional MOET with 12h delay in injection of PGF2α; Group 3, implanted with GnRH agonist to block the pre-ovulatory surge release of LH; Group 4, implanted with GnRH agonist and injected with exogenous LH (Lutropin®, 25mg) 24h after 4 days of superstimulation with FSH; Group 5, implanted with GnRH agonist and injected with LH 36h after superstimulation with FSH. Ovarian follicular growth in all buffaloes was stimulated by treatment with FSH (Folltropin-V®, 200mg) administered over 4 days, and was monitored by ovarian ultrasonography. At the time of estrus, the number of follicles ≥8mm was greater (P<0.05) for buffaloes in Group 2 (12.8) than for buffaloes in Groups 1 (8.5), 3 (7.3), 4 (6.1) and 5 (6.8), which did not differ. All buffaloes were mated by AI after spontaneous (Groups 1–3) or induced (Groups 4 and 5) ovulation. The respective number of buffalo that ovulated, number of corpora lutea, ovulation rate (%), and embryos+oocytes recovered were: Group 1 (2, 1.8±1.6, 18.0±13.6, 0.2±0.2); Group 2 (4, 6.1±2.9, 40.5±17.5, 3.7±2.1); Group 3 (0, 0, 0, 0); Group 4 (6, 4.3±1.2, 69.3±14.2, 2.0±0.9); and Group 5 (1, 2.5±2.5, 15.5±15.5, 2.1±2.1). All buffaloes in Group 4 ovulated after injection of LH and had a relatively high ovulation rate (69%) and embryo recovery (46%). It has been shown that the GnRH agonist-LH protocol can be used to improve the efficiency of MOET in buffalo.

The Peripheral Levels of Luteinizing Hormone(LH), Follicle-Stimulating Hormone(FSH), Immunoreactive(ir-) Inhibin, Progesterone(P) and Estradiol-17.BETA.(E2) at the Time of Control of Ovulation With Gonadotropin Releasing Hormone(GnRH) Agonist(Deslorelin) in Pony Mares.

Control of ovulation in mares obviously has many advantages in a breeding program. Two pony mares were challenged against synthetic Gonadotropin Releasing Hormone (GnRH) agonist (Deslorelin) for six consecutive cycles. Clinical and endocrinological findings after treatment (n=6) with GnRH agonist were compared with those of the control findings before treatment (n=3) of the same mares. The time interval from administration of the GnRH agonist till ovulation (43.5 ± 4.0 hr) and the length of the estrous cycle (19.5 ± 1.0 days) at the time of treatment were significantly (p<0.05) shortened as compared with those of the control. A preovulatory sharp rise in plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) was also noticed 24 hr from the time of GnRH agonist injection and one day prior to ovulation in the studied mares, but there were no significant differences before and after treatment with GnRH agonist on the levels of ir-inhibin, progesterone (P) and estradiol-17 β (E2). It seems likely that GnRH agonist is beneficent in reducing the number of matings needed for conception in a natural mating program and that ovulation in mares may be induced by a sharp preovulatory rise in LH and FSH.

Spawning induction of individual European sea bass females ( Dicentrarchus labrax) using different GnRHa-delivery systems

The present study evaluated the effect of different delivery systems loaded with gonadotropin-releasing hormone agonist (GnRHa) on spawning induction, and egg and larval quality in female European sea bass ( Dicentrarchus labrax). Mature females (mean±S.E.M. oocyte diameter=905±10 μm) were treated with [ d-Ala 6, Pro 9 NEt]-mGnRHa using GnRHa-loaded microspheres, Mc (60 μg kg −1 body weight, bw) GnRHa-loaded implants, EVAc (50 μg kg −1 bw) or received a single injection of GnRHa in saline, IN (15 μg kg −1 bw). Controls (C) were injected with saline. Females were allocated individually in 2-m 3 tanks with two GnRHa-treated males and were allowed to spawn without further handling. All GnRHa treatments induced spawning 3 days after treatment (d.a.t.), whereas control fish did not spawn during the 21-day experimental period. GnRHa microspheres and implants induced up to four consecutive spawns in one female, whereas GnRHa-injected fish spawned only once. Egg quality seemed relatively lower in all GnRHa-treated groups compared to spontaneously spawning fish (natural spawns, NAT group) maintained in large populations (80 fish in 15-m 3 tanks), possibly due to both the isolation of individual females in separate tanks and the stress from handling. Mean egg quality of the first spawns was variable, but similar in all GnRHa treatments (6.6–18.2% buoyancy; 21.7–27.4% hatching). In subsequent spawns, the Mc-treated females produced eggs of higher buoyancy than the EVAc group (20.5±6.0% vs. 2.87±1.14%), and similar to the first spawn of the GnRHa-injected group. Our results indicate that, compared to a single GnRHa injection, GnRHa-loaded microspheres can induce multiple spawns in European sea bass, without a negative effect on egg quality.

Reduction of long-term effects of local heating of the testis by treatment of rats with a GnRH agonist and an anti-androgen.

Heating the testes of anaesthetized adult rats to 43 degrees C for 30 min in a waterbath was followed by a large decrease in testis and epididymis mass and number of spermatozoa 35 days later. These parameters had recovered to some extent, but not completely, by days 70 and 97 after heating, but had decreased again in rats examined on day 182. There were no consistent effects of heating on androgen status, as determined by the concentrations of testosterone in blood and testis fluids, or by seminal vesicle mass, and interstitial fluid volume was increased in the heated testes. Treatment of rats with an implant of a GnRH agonist and daily injections of an anti-androgen for 14 days (sufficient in itself to cause large temporary decreases in tissue mass, number of spermatozoa and androgen status) did not reduce the initial decrease in testis mass or number of spermatozoa seen after heating, but reduced the later decreases in mass and number of spermatozoa significantly. These findings indicate that, as well as causing damage to spermatocytes and spermatids, as previously reported, heating also reduces the ability of spermatogonia to repopulate the seminiferous tubules at longer intervals after heating. Furthermore, it appears that this effect on the spermatogonia can be reduced by treating the animals with a GnRH agonist and anti-androgen, a treatment similar to that shown by other authors to improve recovery of the testis from irradiation or drug treatment.

Reduction of long-term effects of local heating of the testis by treatment of rats with a GnRH agonist and an anti-androgen

Heating the testes of anaesthetized adult rats to 43 degrees C for 30 min in a waterbath was followed by a large decrease in testis and epididymis mass and number of spermatozoa 35 days later. These parameters had recovered to some extent, but not completely, by days 70 and 97 after heating, but had decreased again in rats examined on day 182. There were no consistent effects of heating on androgen status, as determined by the concentrations of testosterone in blood and testis fluids, or by seminal vesicle mass, and interstitial fluid volume was increased in the heated testes. Treatment of rats with an implant of a GnRH agonist and daily injections of an anti-androgen for 14 days (sufficient in itself to cause large temporary decreases in tissue mass, number of spermatozoa and androgen status) did not reduce the initial decrease in testis mass or number of spermatozoa seen after heating, but reduced the later decreases in mass and number of spermatozoa significantly. These findings indicate that, as well as causing damage to spermatocytes and spermatids, as previously reported, heating also reduces the ability of spermatogonia to repopulate the seminiferous tubules at longer intervals after heating. Furthermore, it appears that this effect on the spermatogonia can be reduced by treating the animals with a GnRH agonist and anti-androgen, a treatment similar to that shown by other authors to improve recovery of the testis from irradiation or drug treatment.

Plasma Steroids in Mature Common Dentex (Dentex dentex) Stimulated with a Gonadotropin-Releasing Hormone Agonist

The aim of this study was to identify the major C21 steroids produced in vivo during artificially induced final oocyte maturation and spawning in female common dentex (Dentex dentex). During the spawning season, mature females were treated with a gonadotropin-releasing hormone agonist (GnRHa)-loaded delivery system, with or without pimozide (given as a single dose at the beginning of the experiment). Blood samples were collected at various intervals during the experiment and were assayed for GnRHa, 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P), and 17,20β,21-trihydroxy-4-pregnen-3-one (17,20β,21-P). A higher percentage of ovulated females was observed in GnRHa-implanted fish, which produced over 10 times more eggs than controls. Relative fecundity was highest in the GnRHa + pimozide group and lowest in controls. The viability of naturally released eggs was low (2 to 15%) in all groups. Plasma concentrations of 17,20β-P in GnRHa-implanted fish did not increase, but those in control fish decreased, such that there was a significant difference between control and treated fish between 2 and 10 days after treatment. In another experiment, ovulating common dentex were injected intramuscularly with a single dose of 50 μg kg−1 of GnRHa in saline and were sampled for blood at 0, 3, 6, 12, and 24 h postinjection. A single water sample was taken from the tanks at 9 h postinjection, the tanks having been emptied and refilled at 6 h. Measurements were made of plasma and water concentrations of free and conjugated 17,20β-P, 17,20β,21-P, 17β-oestradiol (E2), and GnRHa (plasma only). The GnRHa injection increased plasma levels of all steroids, with free 17,20β-P reaching maximal levels within 3 h. GnRHa treatment also increased the amounts of free and conjugated steroids released into the water between 6 and 9 h.

Changes in bone turnover following gonadotropin-releasing hormone (GnRH) agonist administration and estrogen treatment in cynomolgus monkeys: a short-term model for evaluation of antiresorptive therapy

In this study we determine the early time course of estrogen deficiency-induced bone loss in the cynomolgus monkey and examine the potential of this method for evaluating antiresorptive therapies. In two groups of animals, estrogen deficiency was induced by the administration of a gonadotropin-releasing hormone agonist (GnRHa) and bone turnover was measured using biochemical markers. Two weeks after receiving GnRHa, serum estradiol decreased to below the detection limit in most animals and remained there through 6 months or until estrogen replacement started (months 4–6). Relative to untreated animals, urinary deoxypyridinoline (dPyr), as well as C- and N-telopeptides of type I collagen, were significantly elevated 4 weeks after receiving GnRHa. Serum osteocalcin increased in GnRHa-treated animals as early as week 4 and the level was significantly higher than in untreated control animals from weeks 8–24. Estradiol treatment returned all measures of bone turnover to control levels within 2 weeks. The use of biochemical markers as surrogates of bone turnover and loss was validated by measurement of bone mineral density (BMD), which showed a significant reduction at 6 months in estrogen-deficient animals. However, lumbar BMD in animals that received GnRHa and estradiol was similar to that in animals that had not received GnRHa. In conclusion, a monthly depot injection of GnRHa resulted in increased bone turnover due to estrogen deficiency, as early as 4 weeks after treatment. Estrogen administration returned bone turnover to control levels in 2 weeks. This method represents a valid model for evaluating antiresorptive agents in the short term in a nonhuman primate. Furthermore, the data suggest that changes in biochemical markers in response to antiresorptive therapy in humans may be detectable at much earlier timepoints than commonly used.

Differential actions of gonadotropin-releasing hormone and human chorionic gonadotropin on interstitial fluid volume and immunoglobulin G concentrations in adult rat testis.

Gonadotropin-releasing hormone (GnRH) agonists regulate testicular interstitial fluid (tIF) volume, most probably via specific receptors on Leydig cells. The aim of this study was to confirm the interaction between GnRH and Leydig cells in regulation of testicular fluid, and to examine the effects on serum proteins in testis. Unilateral intratesticular injection of a GnRH agonist (100 ng/testis) caused a 50% reduction in tIF volume within 2 hours. Destruction of Leydig cells by treatment with ethane dimethane sulfonate also caused a similar decline in tIF volume; however, GnRH agonist treatment had no additional influence on this response in Leydig cell-depleted testes. GnRH agonist treatment had no effect on serum protein permeability in testis as indicated by maintenance of the tIF/serum immunoglobulin G (IgG) concentration gradient. Injection of human chorionic gonadotropin (hCG, 100 IU) had no effect on tIF volume at 2 hours, but increased the permeability of the testicular vasculature to serum IgG. At 20 hours after hCG injection, tIF volume was increased twofold, while the testicular permeability barrier to IgG appeared to have been restored. These data indicate that the acute inhibitory action of GnRH on vascular fluid permeability is dependent upon Leydig cells, confirming that these cells are the primary site of GnRH action on testicular vasculature. The data also indicate that supraphysiological doses of hCG cause a rapid increase in testicular permeability to serum proteins, which occurs prior to the well-characterized stimulation of tIF volume. These data provide further evidence that the concentration of serum proteins in tIF and the volume of tIF are both under regulatory control involving Leydig cells, but are independently regulated.

Effect of day of the estrous cycle at the initiation of a timed artificial insemination protocol on reproductive responses in dairy heifers.

Our objectives were to identify stages of the estrous cycle at which initiation of a timed artificial insemination (Ovsynch/TAI) protocol may reduce pregnancy rates and to monitor ovarian follicle dynamics and corpus luteum development after initiation of the Ovsynch/TAI protocol at different stages of the cycle. Cycling Holstein heifers (n = 24) were injected twice with prostaglandin F2alpha to induce estrus and were scanned by ovarian ultrasonography to determine the day of ovulation (d 0). Heifers were assigned to initiate the Ovsynch/TAI protocol at d 2 (n = 5), 5 (n = 5), 10 (n = 4), 15 (n = 5), or 18 (n = 5) of the cycle. The Ovsynch/TAI was initiated with an injection of gonadotropin-releasing hormone agonist followed 7 d later with an injection of prostaglandin F2alpha. At 36 h after injection of prostaglandin F2alpha, heifers were injected with gonadotropin-releasing hormone agonist and inseminated 16 h later. Heifers were scanned daily during the Ovsynch/TAI protocol and every other day after insemination until 16 d later. Blood samples were collected daily starting at the 1st day heifers were scanned and continued until 16 d after insemination. Initiation of the Ovsynch/TAI protocol at d 15 of the estrous cycle caused heifers to ovulate prior to insemination. A shortened return to estrus (< 16 d) was caused by ovulation failure to the second gonadotropin-releasing hormone injection, by incomplete regression of the corpus luteum, and by short life-span of the induced corpus luteum. Day of the cycle in which the Ovsynch/TAI protocol is initiated affects dynamics of follicular development, plasma progesterone profiles, and occurrence of premature ovulation. Size of the pre-ovulatory follicle was associated positively with subsequent progesterone concentrations following insemination.

Central Precocious Puberty: A Single Blood Sample after Gonadotropin-Releasing Hormone Agonist Administration in Monitoring Treatment

This study was designed to evaluate whether a single blood sample drawn after the home injection of a long-acting gonadotropin-releasing hormone (GnRH) agonist (GnRHa) in patients treated for central precocious puberty (CPP) could be a more simple and inexpensive test with respect to the conventional GnRH stimulating test in assessing adequate suppression of the pituitary-gonadal axis. The response to the first therapeutic injection of the GnRHa triptorelin was studied in 14 newly diagnosed untreated females with CPP. The results were compared with the response that the same patients had to the conventional GnRH stimulation test performed at the time of diagnosis. A significant increase in LH, FSH and E₂ levels was observed 12 h after the triptorelin intramuscular injection; serum peak values of LH (70.3 ± 58.5 IU/l), FSH (44.2 ± 21.7 IU/l) and E₂ (489.7 ± 263.9 pmol/l) were significantly greater than those obtained with the conventional GnRH test (LH 31.4 ± 21.7, p = 0.002; FSH 19.8 ± 10.7, p = 0.001; E₂ 83.3 ± 25, p < 0.001). In particular, the E₂ response, 12 h after triptorelin injection, was clearly consistent with gonadal activation compared to the modest E₂ increase in response to the GnRH test. Thereafter 22 girls who were already being treated with triptorelin for CPP were evaluated to see whether a single blood sample drawn 12 h after the therapeutic home injection of GnRHa could be informative in assessing adequate suppression of the pituitary-gonadal axis. This response was also compared to the conventional GnRH stimulation test performed 2 days before the therapeutic triptorelin injection. In 7 girls with evidence of pubertal progression, the E₂ response following the GnRHa injection (136.3 ± 44.4 pmol/l) was significantly higher with respect to the response after the GnRH stimulation test (73.0 ± 0.0; p < 0.02) indicating an inadequate suppression of the pituitary-gonadal axis. The present data suggest that a single blood sample drawn 12 h after the therapeutic home administration of triptorelin provides a simple, comfortable and inexpensive means of monitoring pituitary as well as gonadal function in girls treated for CPP.

Salmon Thyroid-Stimulating Hormone: Isolation, Characterization, and Development of a Radioimmunoassay

Coho salmon (Oncorhynchus kisutch) thyroid-stimulating hormone (TSH) was isolated by ethanol extraction of pituitary glands from mature coho salmon. Extraction was followed by gel-filtration chromatography on Sephadex G-100 superfine, anion-exchange chromatography on a Whatman DE-52 column, and finally by reverse-phase high-performance liquid chromatography. Fractions were monitored for TSH content by a homologousin vivobioassay and by immunoblots using anti-human TSH β-subunit antisera.In vivotreatment of coho salmon parr with coho salmon TSH caused a dose-dependent increase in plasma thyroxine level similar to that induced by bovine TSH. The N-terminal sequence (25 residues) of the salmon TSH β subunit has 56% sequence identity to that of human TSH β subunit and is identical to the deduced amino acid sequence of trout TSH β subunit. The N-terminal sequence (25 residues) of the salmon TSH α subunit is identical to gonadotropin α-II subunit. Molecular sizes of the α and β subunits are 18,000 and 24,000 daltons, respectively, as estimated by SDS–PAGE. Antiserum generated against salmon TSH, which was preadsorbed with α subunit using an α-subunit affinity column, detected only salmon TSH β subunit by immunoblot and specifically stained thyrotropin-producing cells of the pituitary gland. A homologous radioimmunoassay (RIA) was developed using purified salmon TSH standard, iodinated TSH β subunit, and antiserum generated against salmon TSH. Cross-reactivities of GTH I, GTH II, GTH I β and GTH II β subunits, α subunit, growth hormone, prolactin, and somatolactin were less than 1%. Displacement curves for serial dilutions of plasma and pituitary extracts of various salmonid species, as well as coho salmon pituitary cell culture medium, were parallel to the coho salmon TSH standards. In contrast, plasma of hypophysectomized juvenile coho salmon and pituitary extracts of Pacific tomcod (Microgadus proximus) did not displace bound radiolabeled salmon TSH. Finally,in vivoinjection of juvenile coho salmon with triiodothyronine decreased plasma TSH levels, whereas the goitrogen, methimazole, increased plasma TSH levels. Injection of gonadotropin-releasing hormone agonist did not alter plasma TSH. These data suggest that the RIA is specific for TSH and confirm a negative-feedback relationship between the thyroid hormones and TSH.

Effect of Ruminant Grade Menhaden Fish Meal on Reproductive and Productive Performance of Lactating Dairy Cows

Menhaden fish meal, fed at 0.7 kg/d [2.7% of dietary dry matter (DM)], replaced blood meal and meat and bone meal (2.0% of dietary DM) in the diet fed at dairy A (n = 341) and replaced blood, meat and bone, and corn gluten meals (3.2% of dietary DM) in the diet fed at dairy B (n = 300). Cows consumed the experimental total mixed diets from ~24 to 109 d postpartum. Cows were synchronized for estrus using injections of GnRH agonist at 51 d postpartum, PGF2α 7 d later, and artificial insemination at detected estrus. Resynchronization occurred using the same program if estrus was not detected. Diet failed to alter reproductive responses at synchronized artificial insemination. Pregnancy rate at 120 d postpartum was not altered by diet at dairy A (65.4% vs. 60.2%) but was improved by dietary fish meal at dairy B (31.9% vs. 41.3%; interaction of dairy and diet). The dynamics of corpus luteum regression were altered in cows fed fish meal at dairy B. Dietary fish meal did not influence milk production of cows at dairy A but increased production of milk (2.3 kg/d) and protein (0.1 kg/d) of second parity cows at dairy B. When dietary fish meal was fed to cows at dairy B, production of milk fat and 4% FCM was higher for cows in parity 5 or greater than that for cows in fourth parity.

Changes in plasma luteinizing hormone, testosterone and estradiol-17 beta levels and semen quality after injections of gonadotropin releasing hormone agonist and human chorionic gonadotropin in three dogs with oligozoospermia and two dogs with azoospermia.

Plasma luteinizing hormone (LH) and testosterone (T) levels in three normal male Beagles increased markedly, the LH levels peaking at 30 or 45 min and the T levels at 45 or 60 min respectively, after a subcutaneous injection of 1 microgram kg-1 gonadotropin releasing hormone agonist (GnRH-A). Two Collies and a Great dane diagnosed as oligozoospermic and two Shetland sheep dogs diagnosed as azoospermic by evaluation of semen quality were treated with 1 microgram kg-1 GnRH-A after blood collection. Their plasma levels of LH, T and estradiol-17 beta (E2) were measured by radioimmunoassay for the purpose of investigating the effect of hormone therapy on spermatogenic dysfunction and the mechanism on improvement of semen quality. The semen quality of one of the Collies had improved 4 weeks after the GnRH-A treatment. The dog was treated with GnRH-A again and mated with a bitch 4 days later. The bitch gave birth to five puppies. The other dogs, whose semen quality had not improved, were treated with an intramuscular injection of 500 or 1000 IU human chorionic gonadotrphin (hCG) per animal. Since the semen quality of the other Collie and the Great Dane improved temporarily 2 and 4 weeks, respectively, after hCG treatment, the former was mated with a bitch 5 days later. The bitch gave birth to a litter of seven puppies. These hormone treatments, however, had no effect on the azoospermia in the two Shetland sheep dogs. Although the mean plasma LH and T levels in the dogs with oligozoospermia had been low, their LH levels gradually increased after hormone treatment. There were no marked changes in plasma T or E2 levels. These findings indicate that the semen quality of dogs with oligozoospermia can be temporarily improved between 2 and 4 weeks after a single injection of GnRH-A or hCG and the fertility of the dogs restored by the injection.

Therapeutic approach to ovarian cysts in tamoxifen-treated women with breast cancer

Objectives: To present our clinical experience with gonadotropin-releasing hormone agonist (GnRHa) treatment of tamoxifen-treated women who had developed ovarian cysts, and to discuss the diagnostic and therapeutic options in such cases. Methods: The study included six tamoxifen-treated premenopausal women with breast cancer who developed ovarian cysts and were followed up by our outpatient clinic. Tamoxifen was administered orally (20 mg/day). All patients underwent a pelvic examination and vaginal ultrasound using a 5-MHz vaginal probe. Blood samples for serum gonadotropins, estradiol (E 2) and CA 125 levels were collected at the time of the ovarian cyst detection and every month thereafter. After detection of an ovarian cyst, the women were treated by monthly injections of GnRHa. Results: The patients' mean age was 44 years (range 37–51 years) and all had stage-II or -III breast cancer. The mean duration of tamoxifen administration at the time of ovarian cyst detection was 15 months (range 3–40 months). All six ovarian cysts were found to be simple cysts, measuring more than 30 × 30 mm. Serum E 2 levels of the six patients at the time of ovarian cyst detection were between 939 and 1796 pg/ml and were suppressed to less than 25 pg/ml after GnRHa therapy. After between three and six monthly injections of GnRHa all six ovarian cysts disappeared. On follow-up 6 months later, all patients had a normal pelvic examination. Conclusion: The findings of this preliminary report suggest that GnRHa might be an appropriate treatment for tamoxifen-treated women who develop ovarian cysts. It was demonstrated that the GnRHa caused regression of the ovarian cysts and enabled continuation with the adjuvant tamoxifen treatment.

Use of a gonadotropin-releasing hormone agonist or human chorionic gonadotropin for timed insemination in cattle.

Three experiments were conducted to evaluate a synchronization protocol with AI at a predetermined time. In Exp. 1, 169 dairy heifers were assigned randomly to two groups: 1) timed AI (TAI), consisting of GnRH agonist injection (d 0, 1700), PGF2 alpha injection (d 7, 1700), GnRH agonist injection (d 8, 1700), and AI (d 9, 0800); and 2) AI at estrus (AIE), consisting of GnRH agonist injection (d 0, 1700), PGF2 alpha injection (d 7, 1700), and AI at detected estrus. Pregnancy rate was 25.8% for TAI (n = 89) compared with 48.7% for AIE (n = 80; P < .001). Experiment 2 was comparable to Exp. 1, but the second GnRH agonist injection in TAI was given 48 h after injection of PGF2 alpha. Heifers in TAI (n = 187) were inseminated at detected estrus if estrus occurred within 39 h after administration of PGF2 alpha (n = 47). Pregnancy rates were 45.5% for TAI and 48.0% for AIE (n = 177). Conception rate was reduced for TAI (45.5 [85/187] < 61.2% [85/139]; P < .005). In Exp. 3, the second injection of GnRH agonist, given at 48 h after injection of PGF2 alpha, was replaced with hCG (3,000 IU, i.m.). No differences in pregnancy rate were detected for TAI (52.9% [54/102]) vs AIE (56.1% [55/98]). Conception rate was reduced for TAI (52.9 [54/102] < 72.3% [55/76]; P < .005). Delaying the second GnRH agonist injection by 24 h improved pregnancy rate, but replacing the second injection of GnRH agonist with an injection of hCG did not prevent a reduction in conception rate.

A cellular and endocrine characterization of the original and induced corpus luteum after administration of a gonadotropin-releasing hormone agonist or human chorionic gonadotropin on day five of the estrous cycle.

To determine whether injection of hCG or GnRH-agonist on d 5 after estrus (d 0) has a differential functional effect on an induced and the original corpus luteum (CL), two experiments were conducted. In Exp. 1, nonlactating Holstein cows were injected on d 5 with saline (n = 4; T1), a GnRH-agonist (Buserelin, 8 micrograms i.m.; n = 4; T2), or hCG (1,000 i.u., i.v., and 2,000 i.u., i.m.; n = 4; T3). Induced CL were removed on d 13 and weights were different (GnRH-agonist < hCG). In vitro production of progesterone by CL tissue (microgram/g; microgram/CL) was affected by treatment (GnRH-agonist < hCG) and dose of LH (ng.mL) in culture media. Experiment 2 was a replicate of Exp. 1, except that the original CL was removed on d 17 for in vitro culture. Day-17 CL weights and in vitro production of progesterone by original CL were not affected by treatment. The daily rate of increase of plasma progesterone from d 6 to d 13 differed: saline < GnRH-agonist < hCG (P < .01). From d 14 to 17, the rate of plasma progesterone decrease was not different between treatments. Electron micrographic study of the original and induced CL indicates that LH-like exposure delays involution of steroidogenic luteal cells. In summary, the higher levels of progesterone from d 6 to d 13 of the estrous cycle following an injection of hCG vs GnRH-agonist on d 5 is due to a greater response of hCG-induced CL.

Gonadotropin-releasing hormone agonist therapy reduces postoperative adhesion formation and reformation after adhesiolysis in rat models for adhesion formation and endometriosis

To evaluate the effectiveness of GnRH agonist (GnRH-a) therapy on adhesion formation and reformation in established rat models for surgically induced adhesion formation and endometriosis. Before surgery, female Sprague-Dawley rats were injected with GnRH-a or control diluent. Six days later, rats were assigned to one of four surgical groups: [1] endometriosis, [2] endometriosis sham, [3] adhesion model, or [4] adhesion sham. Three weeks after surgery, a second-look laparotomy was performed, adhesions were scored (0 = no adhesions to 3 = severe adhesions) and mechanically disrupted, and rats received a second GnRH-a or diluent injection either analogous to their initial injection or in a crossover design. Three weeks after the second injection, rats were killed and adhesion reformation was scored. Data were evaluated using nonparameteric tests including Mann-Whitney, Kruskal-Wallis, and Friedman's tests comparing GnRH-a treatments with diluent controls. Preoperative GnRH-a therapy reduced adhesion scores in rats with surgically induced endometriosis (mean +/- SEM; GnRH-a 1.1 +/- 0.2 versus diluent 2.2 +/- 0.2) and adhesions (GnRH-a 0.3 +/- 0.1 versus diluent 0.6 +/- 0.1). Pretreatment GnRH-a therapy did not affect adhesion scores in the endometriosis sham procedure. Combined preoperative and postoperative GnRHa therapy (GnRH-a-GnRH-a) but not postoperative GnRH-a therapy alone (diluent-GnRH-a) reduced adhesion reformation after adhesiolysis in the endometriosis model (GnRH-a-GnRH-a 1.1 +/- 0.3, diluent-GnRH-a 1.6 +/- 0.7), the endometriosis sham (GnRH-a-GnRH-a 0.7 +/- 0.2, diluent-GnRHa 1.8 +/- 0.1), and the adhesion model (GnRH-a-GnRH-a 0.3 +/- 0.2, diluent-GnRHa 1.0 +/- 0.5). No adhesions were observed in the adhesion sham group. Gonadotropin-releasing hormone agonist therapy was successful in reducing adhesion formation and reformation. These studies suggest that GnRH-a therapy for adhesion prevention in women should be explored.

Successful treatment of recurrent uterine bleeding during tamoxifen therapy by endometrial ablation

Recurrent bleeding occurred in a premenopausal breast cancer woman during tamoxifen therapy. This bleeding required three curettages. Atypical hyperplasia and carcinoma were excluded, and the patient was prepared for endometrial ablation with two GnRH agonist injections. An endometrial ablation using the roller ball technique was carried out without complications. Tamoxifen therapy was continued postoperatively. During 24 months' follow-up the patient experienced no bleeding and no endometrium was seen by sonography.

Testicular secretion after pulsatile human menopausal gonadotropin therapy in gonadotropin-releasing hormone agonist desensitized dysspermic men

To evaluate Leydig and Sertoli cell response to prolonged pulsatile stimulation with hMG after pituitary desensitization with the GnRH agonist (GnRH-a) triptoreline in normogonadotropic men with abnormal semen analyses. A group of four oligozoospermic men were investigated in the following manner: [1] basal and GnRH-hCG stimulated activity were assessed in all volunteers; [2] a long-acting form of the GnRH-a triptoreline (3.75 mg every month for 3 months) was given, and its effectiveness was evaluated on day 20; and [3] on that day hMG pulsatile administration was introduced (150 IU per 24 hours in 90-minute pulses) with serial hourly sampling (6 to 7 hours) for measurement of FSH, LH, T, E2, and inhibin on days 20, 41, and 90 from the first GnRH-a injection. Initial evaluation showed normal basal, GnRH, and hCG-stimulated hormone concentrations. Pituitary and gonadal activity were effectively suppressed by GnRH-a when tested on day 20. Pulsatile hMG had no immediate stimulatory effect on gonadal activity (day 20). However, on middle and final evaluations (days 41 and 90), basal T, E2, and inhibin had risen to pre-GnRH-a levels, and, moreover, distinct secretory pulses were seen for these hormones. These findings indicate that suppression of pituitary gonadotropin activity with triptoreline combined with pulsatile hMG stimulation offers a new, useful tool for investigation of the male reproductive system in oligozoospermic men.