Master of Science / Department of Animal Sciences and Industry / Joann M. Kouba / The objective of these studies was to investigate the efficacy of an intravaginal triptorelin acetate (TA) gel as an ovulation-inducing agent in mares. In Exp 1, 24 mares were stratified by parity and age and randomly assigned to 3 treatment groups receiving either: 5 mL TA gel (500 μg TA; TA5), 10 mL TA gel (1,000 μg TA; TA10), or 5 mL vehicle gel only (CON). Following the appearance of a follicle ≥ 25 mm, blood samples were obtained every 24 h until treatment administration for measurement of luteinizing hormone (LH) concentrations. Once a follicle ≥ 35 mm in diameter was detected, treatment was administered intravaginally. Following treatment, blood samples were collected and ovaries were scanned via transrectal ultrasonography every 12 h until 48 h post-ovulation. Both TA5 and TA10 tended (P = 0.08) to experience a brief surge in LH by 12 h post-treatment. Regarding LH concentrations, there was a significant (P < 0.005) treatment by time interaction. The interval from treatment to ovulation was not different (P > 0.05) between groups, nor was there a difference (P > 0.05) in the percentage of mares ovulating within 48 h of treatment administration. We hypothesized that LH was not staying elevated long enough for ovulation to occur in a greater percentage of mares. Furthermore, more frequent sampling and scanning was needed to get a more robust characterization of the effect of TA on LH and a more accurate timeframe for when ovulation was occurring. Experiment 2 involved the same CON and TA5 treatment groups; however, the TA10 treatment was split into two 5-mL doses of TA gel, administered 24 h apart (two 500-μg doses of TA; TA5x2). Blood collection and ultrasonography occurred every 12 h upon detection of a follicle ≥ 25 mm in diameter. Once a follicle ≥ 35 mm was detected, treatment was administered and ultrasonography and blood collection occurred every 6 h until 48 h post-ovulation. Both TA5 and TA5x2 had a significant increase (P < 0.05) in LH by 6 h post-treatment, which was declining by 12 h post-treatment. The second dose administered to TA5x2 failed to elicit an increase in LH (P > 0.05). Overall, the treatment by time interaction was significant (P < 0.005) in regard to LH and the interval from treatment to ovulation was shorter (P < 0.01) in TA5 and TA5x2 compared with CON. In conclusion, TA gel increased LH concentrations and hastened the interval from treatment to ovulation in mares in Exp. 2, but not Exp. 1, without an advantage in the timing of ovulation noted between the 5 or 10-mL doses, or administration of two 5-mL doses given 24 h apart. The results of these studies suggest that further testing is needed to effectively evaluate the efficacy of TA gel as an ovulation-inducing agent in mares.

Gonadotrophin-releasing hormone (GnRH) can inhibit proliferation of multiple reproductive tissue cancer cell lines through direct interaction with GnRH receptors (GnRHR) on tumour cells. GnRH analogues may therefore have a role in treating some cancers. The signalling pathways associated with these inhibitory effects are poorly defined, and characterising them may help to understand therapeutic sensitivity. To elucidate these pathways, transcriptomic and proteomic approaches were used to compare the effects of the GnRH agonist Triptorelin in responsive GnRHR-transfected HEK293 cells (SCL60) and unresponsive (HEK293) cells both in vitro for up to 24h and in vivo for up to 7 days. Gene expression profiling demonstrated that SCL60 gene expression was temporally regulated with Triptorelin treatment, with expression of some genes increased at one time point but decreased at another. Early and mid-phase gene expression changes comprised mainly transcription factors and late changes included the hormonal signalling component CGA. Pathway analysis implicated mitogen-activated protein kinase and cell cycle pathways, supporting the detection of G2/M arrest. Signalling effects within SCL60 xenografts, 4 and 7 days following Triptorelin treatment, were investigated using a phosphoproteomic antibody array. Changes included cell cycle and apoptosis regulators, as well as cell surface receptors and NFκB signalling pathway members. Reverse-phase protein arrays and western blotting also showed that pAkt was decreased and pNFκB-p65 was increased after Triptorelin treatment in vitro. An NFκB inhibitor enhanced the anti-proliferative effect of Triptorelin in SCL60 cells in vitro, suggesting that NFκB acts as a survival factor in the response to GnRHR stimulation. A range of GnRHR expression was observed in breast cancer tumours by immunohistochemistry, and on average GnRHR expression was significantly higher in the Triple Negative Phenotype (TNP) subgroup and in grade 3 tumours. A GnRHR-transfected breast cancer cell line, MCF7-h14, was developed. Despite this expressing a similar level of GnRHR to responsive SCL60 cells, MCF7-h14 cells were not inhibited by GnRHR activation, indicating that a high level of GnRHR is insufficient for the antiproliferative effects of Triptorelin.

Die GnRH-Agonisten-Applikation zur Downregulation vor IvF ist "gold standard", überwiegend im sogenannten langen Protokoll. Die Behandlung soll den vorzeitigen LH-Anstieg mit vorzeitiger Ovulation verhindern. Die unerwünschten Wirkungen sind dosisabhängig und rechtfertigen die Suche nach der optimal niedrigen Dosis des GnRH-Agonisten. Mit dieser Fragestellung wurde eine prospektive randomisierte Dosisfindungsstudie durchgeführt. 200 sterile Frauen zwischen 18 und 38 Jahren erhielten vor der IvF-Behandlung im langen Protokoll die Standarddosis von 4,12 mg Triptorelinazetat-Depot (1 Amp. i.m. = Gruppe B: n = 100) versus 2,1 mg Triptorelinazetat Depot (1/2 Amp. i.m = Gruppe A. n = 100) zur Downregulation. Folgende Parameter wurden bestimmt: E2, LH, Progesteron. Die Behandlungsergebnisse wurden korreliert mittels der Anzahl der gewonnenen Oocyten, der fertilisierten Oocyten, der transferierten Embryonen und der Schwangerschaftsraten pro Embryotransfer. Abgebrochene IvF-Zyklen wurden einzeln analysiert. Bezüglich der Hormonwerte waren beide Gruppen ohne signifikanten Unterschied. In der Gruppe der Patientinnen mit der halbierten Dosis (A) kam es nur in einem Fall zu einer vorzeitigen Luteinisierung, in der Standartdosisgruppe (B) in keinem Fall. Wegen low response wurde in Gruppe A in 5 Fällen die Therapie abgebrochen, versus 3 Fälle in Gruppe B (ns). Ebenfalls vergleichbar war das IvF-outcome, nur die ET-Rate pro begonnener Stimulation zeigte einen signifikanten Unterschied: 88 % (A) versus 96 % (B), p / The GnRH agonist application for the downregulation prior to IVF is 'gold standard', mainly in the so-called long protocol. This should avoid premature ovulations. The dose-dependent, undesired effects justify the search for the optimal low dose of the GnRH agonist. A prospective randomised dose-finding study was carried out in this respect. Among 200 sterile women (18 and 38 years) for the planned IVF and/or IVF / ICSI treatment in the long protocol, n = 100 in group A received 2.1 mg Triptorelinacetate depot (1/2 amp., i.m.) and n = 100 in group B the standard dose of 4.12 mg (1 amp., i.m.) for the downregulation. The hormone values E2, LH, progesterone were determined. The treatment results were compared by means of the number and quality of the oocoytes, the embryo transfers and the pregnancy rates. Cancelled IVF cycles were analysed. With respect to the hormone values, neither of the two groups showed significant differences. A premature luteinization occurred in group A (reduced dose) in only one case; in the standard dose of group B, none occurred. Due to the low response, the therapy was cancelled in 5 cases in group A, in comparison to 3 cases in group B (ns). The IVF outcome showed a comparable result. The only significant difference was the ET rate per started stimulation (p