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GnRH Agonist (gnrh + agonist)
Selected AbstractsMore effective induction of spawning with long-acting GnRH agonist in the shi drum, Umbrina cirrosa L. (Sciaenidae, Teleostei), a valuable candidate for Mediterranean maricultureJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2002A. Barbaro Three experiments of spawning induction in shi drum, Umbrina cirrosa L., were performed in six different commercial Italian hatcheries from May to August (water temperatures: 19,29 °C; salinity: 21,37 p.p.t.). In the first experiment, 119 females (1,4.7 kg), subdivided into 29 lots, were injected with a single dose (2, 5, 8, 10, 15 and 20 ,g kg,1 body weight) of short-acting gonadotropin- releasing hormone agonist (GnRHa-S), des-Gly10,[D-Ala6]-LH-RH ethylamide. In the other two experiments, 85 females (0.7,5.8 kg), subdivided into 22 and four lots, were treated with one (40 or 80 ,g kg,1) or three doses (40 ,g kg,1) of long-acting GnRHa (GnRHa-L), respectively. GnRHa-S stimulated spawning in 69% of the 29 treated lots; the number of eggs laid reached a maximum of 130 000 and a weighted mean of 29 200 total eggs kg,1. GnRHa-L elicited a spawning response in 95% of the 22 one-dose treated lots; the number of laid eggs was higher than with GnRHa-S, reaching a maximum of 213 100 and a weighted mean of 59 400 total eggs kg,1. The yield of developing embryos in 67% of the single GnRHa-L treatments was higher (sometimes up to three times) than with GnRHa-S. Triple treatments of the four lots of females with GnRHa-L always resulted in spawning responses; the best result corresponded to a number of total laid eggs of 358 900 eggs kg,1 with a yield of 177 300 developing embryos. [source] In-vitro Fertilization and Embryo Transfer and Cellular Immunity: Study on Cytokines and T Lymphocyte subpopulations in IVF-ET CyclesJOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 3 2002Mitsutaka Murakami Objectives: To determine whether peripheral T lymphocyte subpopulations and cytokines change during in-vitro fertilization and embryo transfer (IVF-ET) cycles and to evaluate them with regard to pregnancy status and types of infertility. Methods: Peripheral T lymphocyte subpopulations and cytokines in 33 consecutive cycles of IVF-ET were examined. All the women were stimulated with purified FSH and hCG after pituitary suppression with GnRH agonist. Peripheral blood samples were collected before FSH administration, on the day of hCG administration, the day of ET (day 2), day 6 and day 15. We measured plasma estradiol and progesterone levels and plasma interferon-,, interleukin-4 (IL-4), IL-10 and IL-12 levels. Peripheral T lymphocyte subpopulations, T helper type 1 and 2 cells (Th1 and Th2) and T cytotoxic type 1 and 2 cells (Tc1 and Tc2), were analyzed with three-color flowcytometry. Results: There were no changes in the plasma levels of the cytokines or in the proportions of Th1 and Th2 and the proportions of Tc1 and Tc2 in peripheral blood lymphocytes during the IVF-ET cycles. In women with endometriosis, the ratios of Tc1 to CD8+ lymphocytes and the Tc1 to Tc2 ratios before FSH administration were much higher than in women without endometriosis. The ratios of Tc1 to CD8+ lymphocytes were significantly lower in the patients with endometriosis who became pregnant. Conclusions: Peripheral cellular immunity does not change during IVF-ET cycles. In women with endometriosis, the peripheral Tc1 subpopulation is more predominant before ovarian stimulation, suggest- ing that the ratio of Tc1 before ovarian stimulation could be an indicator of fecundity for women with endometriosis. [source] First Service Pregnancy Rates Following Post-AI Use of hCG in Ovsynch and Heatsynch Programmes in Lactating Dairy CowsREPRODUCTION IN DOMESTIC ANIMALS, Issue 4 2010H Karami Shabankareh Contents Lactating dairy cows (n = 667) at random stages of the oestrous cycle were assigned to either ovsynch (O, n = 228), heatsynch (H, n = 252) or control (C, n = 187) groups. Cows in O and H groups received 100 ,g of GnRH agonist, i.m. (day 0) starting at 44 ± 3 days in milk (DIM), and 500 ,g of cloprostenol, i.m. (day 7). In O group, cows received 100 ,g of GnRH (day 9) and were artificially inseminated without oestrus detection 16,20 h later. In H group, cows received 1 mg oestradiol benzoate (EB) i.m., 24 h after the cloprostenol injection and were artificially inseminated without oestrus detection 48,52 h after the EB injection. Cows in C group were inseminated at natural oestrus. On the day of artificial insemination (AI), cows in all groups were assigned to subgroups as follows: human Chorionic Gonadotrophin (O-hCG) (n = 112), O-saline (n = 116), H-hCG (n = 123), H-saline (n = 129), C-hCG (n = 94) and C-saline (n = 93) subgroups. Cows in hCG and saline subgroups received 3000 IU hCG i.m. and or 10 ml saline at day 5 post-AI (day 15), respectively. Pregnancy status was assessed by palpation per rectum at days 40 to 45 after AI. The logistic regression model using just main effects of season (summer and winter), parity (primiparous and pluriparous), method1 (O, H and C) and method2 (hCG and saline) showed that all factors, except method1, were significant. Significant effects of season (p < 0.01), hCG and parity (p < 0.01), and a trend of parity and season (p < 0.1) were detected. A clear negative effect of warm period on first service pregnancy rate was noted (p < 0.01). The pregnancy rate was the lowest in the H protocol during warm period (p < 0.05). Treatment with hCG 5 days after AI significantly improved pregnancy rates in those cows that were treated with the H protocol compared with saline treatments (41.5% vs 24.8%; p < 0.01). O and H were more effective in primiparous than in pluriparous cows (46.1% vs 29.9%; p < 0.1 and 43.6% vs 24.6%; p < 0.01). First service pregnancy rates were higher in primiparous hCG-treated than in pluriparous hCG-treated cows (57.9% vs 32.3%; p < 0.01). The pregnancy rate was higher for the hCG-treated cows compared with saline-treated cows during warm period (37.9% vs 23.6%; p < 0.001). [source] GnRH agonist induces apoptosis in seminiferous tubules of immature rats: direct gonadal actionANDROLOGIA, Issue 4 2010T. Peirouvi Summary To investigate direct gonadal effect of buserelin as an agonist of gonadotrophin releasing hormone, the incidence of apoptotic cell death was measured. Thirty 25-day-old immature Wistar male rats were divided into two groups: treated and control rats. Treated rats were given 1.25 mg buserelin acetate/g body weight control rats received vehicle subcutaneously for 5 days. Formalin-fixed paraffin embedded testicles were then investigated for the morphology of seminiferous tubules and occurrence of apoptosis using haematoxylin-eosin staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling respectively. Immaturity of rats was proved by the morphological characteristics of testis. In contrast to the control rats, significant increase of apoptotic cell death was found in buserelin-treated rats. Apart from the well-known pituitary-testicular function of buserelin as an agonist of gonadotrophin releasing hormone, our findings suggest that it induces apoptotic cell death via direct gonadal action. [source] Using a GnRH agonist to obtain an index of testosterone secretory capacity in the cockatiel (Nymphicus hollandicus) and sulphur-crested cockatoo (Cacatua galerita)AUSTRALIAN VETERINARY JOURNAL, Issue 1-2 2010EM Lovas Objective Validation of a stimulation test for determining the steroidogenic capacity of the parrot testis. The major aim was to characterise testosterone secretion after injection of a gonadotropin-releasing hormone agonist (GnRHa), then use the test to investigate seasonal reproduction in the male cockatiel. Procedure A synthetic GnRHa (buserelin; 8.0 µg of peptide/kg bodyweight) was injected IM into male cockatiels (n = 7) and sulphur-crested cockatoos (n = 3) and serial blood samples collected at 0, 30, 60, 90 and 120 min after administration. Once validated, the technique was subsequently used to examine seasonal changes (23 months) in the testosterone profile of a captive cockatiel population. Results Injection of buserelin resulted in a significant increase in the testosterone concentration of cockatiel plasma, with maximal concentrations occurring at approximately 60 (1.33 ± 0.08 ng/mL) to 90 min (1.22 ± 0.08 ng/mL) after injection. Although no clear pattern of seasonal variation in testosterone secretion was detected in cockatiel plasma, samples taken 60 and 90 min after administration showed a significant increase in all seasons. Injection of buserelin in the sulphur-crested cockatoo also resulted in increased testosterone secretion, with maximal concentrations obtained after 90 min. Conclusion Buserelin can be used to obtain a reliable index of the prevailing testosterone capacity of the cockatiel and cockatoo testis. With further studies, this test may be incorporated into clinical assessment of reproductive status. [source] Oestrogen deficiency causes DNA damage in uterine leiomyoma cells: a possible mechanism for shrinkage of fibroids by GnRH agonistsBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 1 2001Ya-Min Cheng Objective To examine whether gonadotrophin-releasing hormone agonist or oestradiol can directly affect DNA in leiomyoma cells. Design In vitro explant culture of leiomyoma cells. Setting University research group. Sample Leiomyoma cells were cultured from the specimens of four premenopausal women at myomectomy. Methods The presence of gonadotrophin-releasing hormone receptor in leiomyoma cells was determined by reverse transcriptase,olymerase chain reaction. Leiomyoma cells were treated with gonadotrophin-releasing hormone agonist or cultured in different concentrations of oestrogen, progesterone or fetal calf serum for one, four or seven days. Main outcome measures Cell number, expression of proliferating cell nuclear antigen, and DNA damage after one, four or seven days of treatment. Results Gonadotrophin-releasing hormone receptor messenger ribonucleic acid was detected on cultured leiomyoma cells. Leiomyoma cell growth was not affected by the addition of gonadotrophin-releasing hormone agonist or progesterone, but increased with oestrogen or fetal calf serum supplementation. Overexpression of proliferating cell nuclear antigen was prevented in cultures added with oestrogen or fetal calf serum, but not related to gonadotrophin-releasing hormone agonist treatment. Significant decreases in DNA damage as indicated by decreased comet number were found in the leiomyoma cultures treated with oestrogen or fetal calf serum for four and seven days but not with gonadotrophin-releasing hormone agonist or progesterone. Furthermore, 5% fetal calf serum supplementation was more growth supporting and more significantly reduced the comet number than 250 pM 17 , -oestradiol. Conclusion Cell growth, proliferating cell nuclear antigen expression and DNA damage are dependent on oestrogen or fetal calf serum, but independent of gonadotrophin-releasing hormone agonist or progesterone. Our findings suggest that gonadotrophin-releasing hormone agonist-induced leiomyoma shrinkage may be due in part to a mechanism involving DNA damage, and support the hypothesis that gonadotrophin-releasing hormone agonist exerts its action indirectly through oestrogen action on the tumour level. [source] | |||||||||||||||||||