The administration of GnRH and its agonists benefits various aspects of bovine reproductive programs, encompassing physiological stages such as estrous synchronization, post-insemination, pregnancy, and the postpartum period. The positive impact of GnRH administration in overcoming challenges like repeat breeder cows, early embryonic loss prevention, and the management of cystic ovarian disease (COD) is thoroughly surveyed. Furthermore, this review focuses on the significance of GnRH administration during the postpartum period, its role in ovulation induction, and how it enhances the productivity of embryo transfer (ET) programs. An emerging feature of this field is introduced, focusing on nano-drug delivery systems for GnRH agonists, and the potential benefits that may arise from such advancements are highlighted. While this review offers valuable insights into various applications of GnRH in bovine reproduction, it emphasizes the crucial need for further research and development in this field to advance reproductive efficiency and health management in dairy cattle.

GnRH is essential for the regulation of mammalian reproductive processes. It regulates the production and release of pituitary gonadotropins, thereby influencing steroidogenesis and gametogenesis. While primarily produced in the hypothalamus, GnRH is also produced in peripheral organs, such as the gonads and placenta. GnRH analogs, including agonists and antagonists, have been synthesized for the reproductive management of animals and humans. This review focuses on the functions of hypothalamic GnRH in the reproductive processes of cattle. In addition to inducing the surge release of LH, the pulsatile secretion of GnRH stimulates the pituitary gland to release FSH and LH, thereby regulating gonadal function. Various GnRH-based products have been synthesized to increase their potency and efficacy in regulating reproductive functions. This review article describes the chemical structures of GnRH and its agonists. This discussion extends to the gene expression of GnRH in the hypothalamus, highlighting its pivotal role in regulating the reproductive process. Furthermore, GnRH is involved in regulating ovarian follicular development and luteal phase support, and estrus synchronization is involved. A comprehensive understanding of the role of GnRH and its analogs in the modulation of reproductive processes is essential for optimizing animal reproduction.

Spermatogonial stem cell (SSC) acquisition of meiotogenetic state during puberty to produce genetically diverse gametes is blocked by drugs collectively referred as \'puberty blocker\' (PB). Investigating the impact of PB on juvenile SSC state and function is challenging due to limited tissue access and clinical data. Herein, we report largest clinically annotated juvenile testicular biorepository with all children with gender dysphoria on chronic PB treatment highlighting shift in pediatric patient demography in US. At the tissue level, we report mild-to-severe sex gland atrophy in PB treated children. We developed most extensive integrated single-cell RNA dataset to date (>100K single cells; 25 patients), merging both public and novel (52 month PB-treated) datasets, alongside innovative computational approach tailed for germ cells and evaluated the impact of PB and aging on SSC. We report novel constitutional ranges for each testicular cell type across the entire age spectrum, distinct effects of treatments on prepubertal vs adult SSC, presence of spermatogenic epithelial cells exhibiting post-meiotic-state, irrespective of age, puberty status, or PB treatment. Further, we defined distinct effects of PB and aging on testicular cell lineage composition, and SSC meiotogenetic state and function. Using single cell data from prepubertal and young adult, we were able to accurately predict sexual maturity based both on overall cell type proportions, as well as on gene expression patterns within each major cell type. Applying these models to a PB-treated patient that they appeared pre-pubertal across the entire tissue. This combined with the noted gland atrophy and abnormalities from the histology data raise a potential concern regarding the complete \'reversibility\' and reproductive fitness of SSC. The biorepository, data, and research approach presented in this study provide unique opportunity to explore the impact of PB on testicular reproductive health.

The lipid profile is affected following menstrual cessation (MC). We aimed to evaluate the effects of goserelin-induced MC and subsequent menstrual restoration (MR) on lipid metabolism. Premenopausal women with histologically verified endometriosis (n = 15) received goserelin monthly for 6 months (6mο), resulting in MC, and were followed-up for another 6 months after MR (12mο). Serum total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB), lipoprotein a ([Lp(a)] and lipidomics were measured at baseline, 6mo and 12mo. Shotgun quantitative deep lipidomics were determined at the level of lipid class category, subclass, species, and fatty acyl chain lengths and degree of saturation. TC (p = 0.006), LDL-C (p = 0.028), HDL-C (p = 0.002), and apoA1 (p = 0.013) increased during goserelin-induced MC and remained practically unchanged during MR. TG, apoB, and Lp(a) did not change. From the deep lipidomics analysis, multivariate statistical analysis demonstrated profound alterations in lipid species with MC, whereas no statistically valid models could be fitted for the restoration period. In conclusion, GnRH-analog-induced MC alters lipid profiles at various levels, from standard blood lipid and lipoprotein profiles to several lipid species as detected by lipidomics analysis. Changes largely persist for at least 6 m after MR.

The objective of this study was to describe the effect of the third-generation GnRH antagonist, acyline, on ovarian follicular population and serum anti-Müllerian hormone (AMH) concentrations in female dogs. Four late anestrous bitches were administered 330 μg/kg SC acyline every 10 days for 60 days and followed up for 45 days. Blood samples were drawn on days -1, 15, 30, 45, 60, 75, 90 and 105 for AMH determination. Then, the females were ovariectomized and the excised ovaries were gross and histologically evaluated. The total ovarian follicles were counted. None of the female dogs presented estrus during treatment. Only one bitch presented an ovulatory estrus 20 days after treatment. The total number of ovarian follicles in these bitches was 96,200.10 ± 26,125.12, with 84.13%, 11.36%, 7.8% and 0.01% corresponding to primordial, primary, secondary and antral structures, respectively. Pretreatment AMH concentrations were 0.62 ± 0.17 ng/mL. This hormone varied throughout the study period (p < 0.01), diminishing to nadir values during treatment to then rapidly recover after its effect (0.2 ± 0.05 vs. 0.67 ± 0.22 ng/mL; p < 0.01). Acyline rapidly and reversibly prevented the initiation of cycling without affecting follicle count but diminishing serum AMH concentrations.

Oocytes/embryo cryopreservation and ovarian function suppression with gonadotropin-releasing hormone (GnRH) agonists (GnRHas) are two established strategies for preserving fertility in patients with cancer, frequently both being offered to the same woman. As the first injection of GnRHa should be administered before chemotherapy, it is usually performed in the luteal phase of the urgent controlled ovarian stimulation (COS) cycle. The GnRHa flare-up effect on recently stimulated ovaries may cause ovarian hyperstimulation syndrome (OHSS) and this risk may discourage some oncologists to offer an ovarian function preservation method with proven efficacy. We suggest the long-acting GnRHa as an option to trigger ovulation for egg retrieval in oncological patients, whenever ovarian suppression during chemotherapy is planned.
We retrospectively analyzed prospectively collected data from all consecutive ovarian stimulation cases in oncological patients for oocyte cryopreservation from 2016 to 2021 in a single academic referral center. The COS was performed according to good clinical practice standards. Since 2020 long-acting GnRHa trigger was offered to all patients for whom ovarian suppression after cryopreservation was planned. All other patients served as controls, stratified for the triggering method used: highly purified chorionic gonadotrophin 10 000 UI or short-acting GnRHa 0.2 mg.
Mature oocytes were collected, with the expected maturation rate, in all the 22 cycles triggered with GnRHa. The mean number of cryopreserved oocytes was 11.1 ± 4, with a maturation rate of 80% (57%-100%), versus 8.8 ± 5.8, 74% (33%-100%) with highly purified chorionic gonadotrophin and 14 ± 8.4, 80% (44%-100%) with short-acting GnRHa. No case of OHSS was observed after long-acting GnRHa triggering and by 5 days after egg retrieval most patients had reached luteinizing hormone levels showing suppression.
Our preliminary data show that long-acting GnRHa is efficacious in inducing the final oocytes\' maturation, reducing OHSS risk and suppressing ovarian function by the start of chemotherapy.

UNASSIGNED: Premenopausal patients with hormone receptor-positive breast cancer require ablation therapy via a pharmacological or surgical approach. Data comparing outcomes between treatment with gonadotropin-releasing hormone (GnRH) analogs and treatment with bilateral salpingo-oophorectomy (BSO) in Indonesia remains limited. Therefore, this study aimed to compare incidence of local recurrence and metastasis, and overall survival (OS) in patients with luminal type breast cancer treated using the two approaches.
UNASSIGNED: This observational retrospective cohort study examined 100 premenopausal patients diagnosed with luminal type hormone receptor-positive breast cancer who registered at Dr. Wahidin Sudirohusodo Hospital and its networking hospitals in Makassar City from January to December 2017.
UNASSIGNED: Among the 100 study patients, 50 were given GnRH analogs and 50 underwent BSO. Incidence of local recurrence (P = 0.408) and metastasis (P = 0.419) did not significantly differ between the GnRH analog and BSO groups, although the incidence of local recurrence was higher in the GnRH analog group (68% vs. 58%) and incidence of metastasis was higher in the BSO group (24% vs 19%). The 5-year survival rate did not significantly differ between the GnRH analog and BSO groups.
UNASSIGNED: Incidence of local recurrence and metastasis, and 5-year survival rate did not significantly differ between premenopausal breast cancer patients treated using a GnRH analog and those treated with BSO. Further large-scale studies to compare the efficacy and safety of both approaches are warranted.

UNASSIGNED: Anti-Müllerian hormone (AMH) is the most reliable biomarker of ovarian reserve; however, its role in predicting ovarian recovery after chemotherapy is unclear. Administration of a GnRH analog (GnRHa) during chemotherapy significantly reduces the ovarian failure rate and increases the pregnancy rate. The available data on the behavior of AMH during concurrent administration of chemotherapy and GnRHa are inconsistent. We investigated whether concurrent administration of triptorelin and adjuvant chemotherapy might reduce the expected drop of AMH.
UNASSIGNED: Eligible patients were premenopausal women aged <40 years, with a diagnosis of early breast cancer, and candidates to 4-8 cycles of adjuvant chemotherapy. Triptorelin (3.75 mg i.m.) was started before chemotherapy and administered every 4 weeks thereafter. The principal endpoint was the proportion of patients with an AMH percent change ≤50% between 12 months after chemotherapy and basal levels. The secondary endpoint was the proportion of patients achieving postchemotherapy AMH levels above the threshold of 0.2 ng/mL.
UNASSIGNED: Fifty patients were enrolled, 31 of whom had blood samples available at baseline and 1 year after the end of chemotherapy. AMH decreased to nearly undetectable levels after chemotherapy and recovered after 12 months, but they did not exceed 1 tenth of the pretreatment levels. As for the secondary endpoint, 15 of the 31 patients recovered AMH levels above the threshold.
UNASSIGNED: This study did not reach its principal endpoint; however, the rate of 48% of patients who recovered AMH above threshold levels favorably compared with those in studies without concurrent GnRHa, supporting a better recovery of AMH with triptorelin.

UNASSIGNED: Rapidly progressive precocious puberty (RPPP) is a rare condition in Turner syndrome (TS), with no consensus on treatment and follow-up. Only 12 cases have been reported so far.
UNASSIGNED: We aimed to evaluate the effects of the GnRH analog (GnRHa) on growth and anti-mullerian hormone (AMH) levels in TS and RPPP.
UNASSIGNED: The clinical and laboratory data was recorded at baseline and after treatment.
UNASSIGNED: An 8.1-year old girl with a karyotype of 45, X/46, XX presented with breast development at Tanner stage-2. Breast development advanced to Tanner stage-3 at the age of 8.7 years. Growth velocity (GV) was 8 cm/year. Bone age was 11 years with a predicted adult height of 152 cm. Luteinizing hormone (LH) was 1.69mIU/mL and estradiol was 33pg/mL, confirming the central puberty. AMH level was 6.33ng/mL. The sizes of ovaries and uterus were compatible with the pubertal stage, with an endometrial thickness of 5 mm. GnRHa was started for RPPP.
UNASSIGNED: After three months, GV declined to 0 cm/3 months and AMH level to 50% of the baseline. Growth hormone (GH) treatment was started for insufficient growth. GV improved with GH treatment, as well as a far more decreased AMH level.
UNASSIGNED: After three months, GV declined to 0 cm/3 months and AMH level to 50% of the baseline. Growth hormone (GH) treatment was started for insufficient growth. GV improved with GH treatment, as well as a far more decreased AMH level.
UNASSIGNED: GV usually declines before puberty in patients with TS, even if the mid-parental height is tall. RPPP should be considered if GV is increased. Excessive suppression of growth may be prevented with GH treatment. GnRHa treatment also plays a role in reducing AMH levels in patients with TS.

Long-acting gonadotropin-releasing hormone (GnRH) analogs, which are approved for male dogs and ferrets, have been used off-label to suppress estrus in bitches predisposed to the side effects of spaying. Health data from the past 12 years were evaluated from bitches without progestogen pretreatment that received deslorelin acetate (DA) to suppress estrus for the first time before the age of 4.5 years. The study population included 32 client-owned bitches repeatedly treated with either 4.7 mg or 9.4 mg DA implants for a period of 5.3 ± 3.4 years (range 0.5-11.3 years). Follow-up information concerning immediate side effects of DA occurring within five months after the first DA treatment (n = 23) as well as long-term side effects of sustained gonadal suppression occurring after five months up to three years (n = 2), three years up to five years (n = 2) or more than five years (n = 8) were assessed through a questionnaire. Treatment was considered successful if no major side effects requiring medical treatment occurred, which applied to 26 out of 32 (81 %) bitches. In the six remaining bitches, the following major side effects led to treatment discontinuation: persistent urinary incontinence (n = 1), reoccurring induced heat (n = 1), uterine disease (n = 3) and/or ovarian tumor (n = 3). The bitches recovered completely after surgical spaying and/or DA implant removal. Minor side effects that did not require therapy or affect animal welfare included body weight changes (n = 18), subtle behavioral changes (n = 13), induced heat (n = 12), coat changes (n = 11), pseudocyesis (n = 6), transient urinary incontinence (n = 4), and/or temporary thickening of the uterine wall with little anechogenic content (n = 2). To examine a possible causal relationship between adverse side effects and DA treatment, further studies should compare the frequency of pathologies between groups of GnRH-treated, intact and spayed bitches of similar breeds and ages. Nevertheless, DA application before the age of 4.5 years may be a means of postponing surgical spaying for several years in breeds at high risk for developing urinary incontinence. Before DA is used in bitches, owners should be fully informed regarding possible side effects.