Pituitary Luteinizing Hormone Research Articles

P-708 melatonin alleviates circadian rhythm disruption-induced enhanced luteinizing hormone pulsatility and ovarian dysfunction in vivo and in vitro

Abstract Study question Is melatonin deficiency a reversible cause of abnormal pattern of luteinizing hormone (LH) pulsatility and ovarian dysfunction caused by circadian rhythm disruption (CRD)? Summary answer Melatonin could rescue the augmented LH pulsatility and reproductive abnormalities caused by CRD. What is known already Melatonin, mainly synthesized and released by pineal gland, engages in regulating circadian rhythms. When circadian rhythms are disrupted, the nocturnal productions of melatonin are suppressed. Evidence suggests that circadian rhythm disruption (CRD) is associated with reproductive dysfunctions, while melatonin plays a vital role for female reproduction as a free radical scavenger and a neuroendocrine regulator. The gonadotrophin-releasing hormone (GnRH) drives pulsatile luteinizing hormone (LH) secretion, which is also essential for fertility. Study design, size, duration We used 90 CBA/CaJ mice to establish the chronic jet-lag model in which mice were exposed to an 8 hr time shift every 3 days. After 8 weeks of jet-lag induction, some of the mice were given melatonin treatment for 4 weeks. Furthermore, we used a perfusion system in vitro to mimic the process of CRD-induce high-frequency GnRH pulses stimulation of LβT2 gonadotrope cells. Participants/materials, setting, methods Repetitive tail-tip blood collection was used to evaluate the pattern of LH pulsatility. Blood plasma samples were collected from 4 mice at 4-hour intervals to measure levels of melatonin. Follicular development was evaluated by ovarian histology. Reproductive hormones was detected by ELISA. Immunohistochemistry and western blot were used to detect the expression of melatonin receptor 1A (MT1). The LβT2 cells were exposed to pulsatile GnRH at high pulse frequencies to mimic augmented pulsatile GnRH stimulation. Main results and the role of chance CRD mice exhibited reproductive-endocrine dysfunction, including irregular estrous cycles, reduced number of corpus lutea (CL), and decreased levels of estradiol and progesterone. Additionally, CRD enhanced the frequency and amplitude of LH pulsatility and pituitary LH beta-subunit expression. Melatonin administration alleviated these CRD-induced reproductive abnormalities and reversed the augmented LH pulsatility. The expression of MT1 decreased in the anterior pituitaries of CRD mice but increased after melatonin treatment, indicating the essential role of MT1 in melatonin’s reversal of CRD-induced enhanced LH pulsatility. Limitations, reasons for caution Further research is needed to validate the applicability and safety of these findings in humans. Wider implications of the findings The results suggest that melatonin may be a beneficial option for patients with reproductive-endocrine abnormalities, particularly those with circadian rhythm disruption. Trial registration number 82101719

Characterization of a novel fast-growing zebrafish: a new approach to growth hormone transgenesis.

The manipulation of the somatotropic axis, governing growth, has been a focus of numerous transgenic approaches aimed at developing fast-growing fish for research, medicine and aquaculture purposes. However, the excessively high growth hormone (GH) levels in these transgenic fish often result in deformities that impact both fish health and consumer acceptance. In an effort to mitigate these issues and synchronize exogenous GH expression with reproductive processes, we employed a novel transgenic construct driven by a tilapia luteinizing hormone (LH) promoter. This approach was anticipated to induce more localized and lower exogenous GH secretion. In this study, we characterized the growth and reproduction of these transgenic LHp-GH zebrafish using hormonal and physiological parameters. Our findings reveal that LHp-GH fish exhibited accelerated growth in both length and weight, along with a lower feed conversion ratio, indicating more efficient feed utilization, all while maintaining unchanged body proportions. These fish demonstrated higher expression levels of LH and GH in the pituitary and elevated IGF-1 levels in the liver compared to wild-type fish. An examination of reproductive function in LHp-GH fish unveiled lower pituitary LH and FSH contents, smaller follicle diameter in female gonads, and reduced relative fecundity. However, in transgenic males, neither the distribution of spermatogenesis stages nor sperm concentrations differed significantly between the fish lines. These results suggest that coupling exogenous GH expression with endogenous LH expression in females directs resource investment toward somatic growth at the expense of reproductive processes. Consequently, we conclude that incorporating GH under the LH promoter represents a suitable construct for the genetic engineering of commercial fish species, providing accelerated growth while preserving body proportions.

Comparing blastocyst euploid rates between the progestin-primed and gonadotrophin-releasing hormone antagonist protocols in aneuploidy genetic testing: a randomised trial protocol

IntroductionProgestin can inhibit the pituitary luteinising hormone (LH) surge during ovarian stimulation for in vitro fertilisation (IVF) and studies show progestin-primed ovarian stimulation (PPOS) is effective in blocking the LH...

#390 : Why Our Clinical Pregnancy Rates Have Improved Over the Past Two Years: Exploring Key Points of Gonadotropin-Releasing Hormone Antagonist Protocol in Fresh Embryo Transfer Cycles

Background and Aims: GnRH-ant protocol is effective in preventing a surge of pituitary luteinising hormone during controlled ovarian stimulation. In recent years, GnRH-ant protocol has been optimised to improve in vitro fertilisation outcomes. However, firstly, the success rate of frozen embryo transfer is consistently better than that of fresh embryo transfer and secondly, the success rate of GnRH-ant protocol on fresh embryo transfer is lower than that of the long protocol. This study aims to draw out a comparison of before and after data from our own centre to find the reasons for the gradual maturation of GnRH-ant protocol on fresh embryo transfer. Our study proposed to investigate the determinants affecting fresh embryo transfer in gonadotropin-releasing hormone antagonist (GnRH-ant) protocols. Method: We reviewed 2464 fresh embryo transfer cycles for IVF/ICSI-ET assisted reproduction techniques performed at our centre from 1 January 2015 to 31 December 2019. The exclusion criteria were as follows: endometriosis grade III to IV (American Fertility Society classification of endometriosis); adenomyosis; severe male oligospermia or obstructive azoospermia. Firstly, we compared the single-cycle clinical pregnancy rates between 2015 to 2017 and 2018 to 2019. Next, we performed a multifactorial regression analysis to understand what changes our centre had made between the five years in terms of years. Finally, data from 2015 to 2019 were grouped as a whole and then subjected to understand exactly where the differences in clinical pregnancy rates were affecting the GnRH-ant protocol for fresh embryo transfer. Results: A total of 1,388 cycles were included from 2015 to 2017, with a clinical pregnancy rate of 51.42% (688/1388). 1,076 cycles were included from 2018 to 2019, with a clinical pregnancy rate of 57.43% (618/1076). 2018 to 2019 compared to 2015 to 2017 for first-time IVF/ICSI. There was a 6.01% increase in clinical pregnancy rate for women who had assisted conception and performed GnRH-ant protocol with fresh embryo transfer. The results of the univariate analysis conducted suggested that the factors influencing the classification of clinical pregnancy included female basal E2 base, LH base, FSH base, P base, female Gn initiation date E2 start, LH start, FSH start, P start, Gn initiation volume and number of Gn days, antagonist addition date E2 add, LH add, FSH add, P add, plate machine day E2 trigger, LH trigger, P trigger, plate machine day number of different follicles in the meridian follicles 10-14 mm, follicles 14-16 mm, follicles 16-18 mm, follicles 18mm or more. Multifactorial regression analysis after correction suggested that age, BMI, endometrial thickness on the day of transfer, number of embryos transferred and progesterone level on HCG Day were independent influencing factors for successful pregnancy with antagonist regimen and fresh embryo transfer. Conclusion: Age, BMI, endometrial thickness on the day of transfer, number of embryos transferred and progesterone levels on HCG Day were independent influences.

FRI168 LH-hCG Receptor Is Expressed In All Three Zones Of Normal Adrenal Glands But Not In Aldosterone-Producing Micronodules

Abstract Disclosure: S.A. Reda: None. A. Kirschenbaum: None. S. Yao: None. L. Milgram: None. J. Rege: None. A.C. Levine: None. Embryologically, the adrenals and gonads develop from the urogenital ridge with differential migration and differentiation. Post-natally, pituitary adrenocorticotropic hormone (ACTH) stimulates adrenal cortical cell growth and steroidogenesis, whereas pituitary luteinizing hormone (LH) regulates gonadal cell growth and steroidogenesis. However, there are multiple reports of gonadal tumorigenesis driven by high ACTH (in congenital adrenal hyperplasia) and adrenal cortical tumorigenesis driven by high LH/human chorionic gonadotropin (hCG) levels (adrenal tumors in pregnant and postmenopausal females). We studied the immunohistochemical expression of LH/hCG receptor (LH/hCG-R) in normal adrenal glands from 12 kidney donors (four male and eight female, two of which were <50 years of age and six were >50 years of age). Some of these specimens also contained aldosterone producing micronodules (APMs). Staining was performed for Synaptophysin, aldosterone synthase (CYP11B2), LH/hCG-R, WNT/β-Catenin, and DLK-1. In normal adrenal tissue, we first used synaptophysin stain to identify the nerves in the adrenal cortex as well as the adrenal medulla (M). CYP11B2 staining demonstrated immunoreactivity in a linear pattern throughout the Zona Glomerulosa (ZG) in five of the 12 samples. Faint expression of LH/hCG-R was detected in all twelve samples throughout the three layers of the adrenal cortex: the ZG, Zona Fasciculata (ZF) and Zona Reticularis (ZR). However, there were occasional cells in both the ZR and ZF that stained intensely for LH/hCG-R expression. LH/hCG-R immunoreactivity was also noted in the progenitor-rich subcapsular (SC) region. WNT β-Catenin, a transcription factor involved in the proliferation of adrenal cortical cells, stained most heavily in the SC/ZG region, possibly representing adrenal cortical progenitor cells. DLK-1, an adrenal cortical progenitor cell marker, was also expressed in the subcapsular zone. In adrenal tissues containing APMs, CYP11B2 immunostaining revealed areas of CYP11B2 positive cells that dip into the ZF, with no preserved linear staining for CYP11B2 in the ZG. LH/hCG-R stained most densely in the SC and ZG regions, with little to no immunoreactivity in the APMs. WNT β-Catenin likewise stained the SC and ZG regions with no expression in the APMs. Our findings suggests that LH/hCG-R is expressed sporadically in normal adrenal cortical tissue, but densely at times in all three zones of the adrenal cortex and the subcapsular area where the putative adult progenitor cells reside. The LH/hCG-R does not appear to be expressed throughout the entirety of APMs. Presentation: Friday, June 16, 2023

Pre- and postnatal developmental exposure to the polychlorinated biphenyl mixture aroclor 1221 alters female rat pituitary gonadotropins and estrogen receptor alpha levels

Polychlorinated-biphenyls (PCBs) are industrial compounds, which were widely used in manufacturing of electrical parts and transformers. Despite being banned in 1979 due to human health concerns, they persist in the environment. In humans and experimental model systems, PCBs elicit toxicity in part by acting as endocrine-disrupting chemicals (EDCs). Aroclor 1221 (A1221) is a weakly estrogenic PCB mixture known to alter reproductive function in rodents. EDCs can impact hormone signaling at any level of the hypothalamic-pituitary-gonadal (HPG) axis, and we investigated the effects of A1221 exposure during the prenatal and postnatal developmental periods on pituitary hormone and steroid receptor expression in female rats. Examining offspring at 3 ages, postnatal day 8 (P8), P32 and P60, we found that prenatal exposure to A1221 increased P8 neonate pituitary luteinizing hormone beta (Lhb) mRNA and LHβ gonadotrope cell number while decreasing LH serum hormone concentration. No changes in pituitary hormone or hormone receptor gene expression were observed peri-puberty at P32. In reproductively mature rats at P60, we found pituitary follicle stimulating hormone beta (Fshb) mRNA levels increased by prenatal A1221 exposure with no corresponding alterations in FSH hormone or FSHβ expressing cell number. Estrogen receptor alpha (ERα) mRNA and protein levels were also increased at P60, but only following postnatal A1221 dosing. Together, these data illustrate that exposure to the PCB A1221, during critical developmental windows, alters pituitary gonadotropin hormone subunits and ERα levels in offspring at different phases of maturation, potentially impacting reproductive function in concert with other components of the HPG axis.

Persistently expressed human chorionic gonadotropin induces premature luteinization and progressive alterations on the reproductive axis in female mice

The hypothalamic–pituitary–gonadal axis plays a fundamental role in the endocrine regulation of the reproductive function in mammals. Any change in the function of the participating hormones or their receptors can lead to alterations in sexual differentiation, the onset of puberty, infertility, cancer development, and other dysfunctions. In this study, we analyzed the influence of persistently elevated levels of the human chorionic gonadotropin hormone (hCG), a powerful agonist of pituitary luteinizing hormone (LH), on the reproductive axis of female mice. As a consequence of chronic hCG hypersecretion through a global expression of the hCGbeta-subunit in transgenic (TG) female mice, a series of events perturbed the prepubertal to juvenile transition. The imbalance in gonadotropin action was first manifested by precocious puberty and alterations in gonadal hormone production, with the consequent ovarian function disruption and infertility in adulthood. The expansion of cumulus cells in vivo and in vitro, ovulatory capacity, and gene expression of ovulation-related marker genes after hormone stimulation were normal in 3-week-old TG females. However, the expression of genes related to steroidogenesis and luteinization such as Lhcgr, Prlr, and the steroidogenic enzymes Cyp11a1, Cyp17a1, and Cyp19a1 were significantly elevated in the TG females. This study demonstrates that the excessive secretion of hCG in concert with high prolactin, induced premature luteinization, and enhanced ovarian steroidogenesis, as was shown by the up-regulation of luteal cell markers and progesterone synthesis in the TG mice. Furthermore, progressively impaired reproductive function of the TG females occurred from the peripubertal stage to adulthood, thus culminating in infertility.

Common and female-specific roles of protein tyrosine phosphatase receptors N and N2 in mice reproduction

Simultaneous knockout of the neuroendocrine marker genes Ptprn and Ptprn2, which encode the protein tyrosine phosphatase receptors N and N2, causes infertility in female mice while males are fertile. To elucidate the mechanism of the sex-specific roles of Ptprn and Ptprn2 in mouse reproduction, we analyzed the effects of their double knockout (DKO) on the hypothalamic-pituitary–gonadal axis. In DKO females, delayed puberty and lack of ovulation were observed, complemented by changes in ovarian gene expression and steroidogenesis. In contrast, testicular gene expression, steroidogenesis, and reproductive organs development were not significantly affected in DKO males. However, in both sexes, pituitary luteinizing hormone (LH) beta gene expression and LH levels were reduced, as well as follicle-stimulating hormone beta gene and gonadotropin-releasing hormone (GnRH) gene, while the calcium-mobilizing and LH secretory actions of GnRH were preserved. Hypothalamic Gnrh1 and Kiss1 gene expression was also reduced in DKO females and males. In parallel, a significant decrease in the density of immunoreactive GnRH and kisspeptin fibers was detected in the hypothalamic arcuate nucleus of DKO females and males. The female-specific kisspeptin immunoreactivity in the rostral periventricular region of the third ventricle was also reduced in DKO females, but not in DKO males. These data indicate a critical role of Ptprn and Ptprn2 in kisspeptin-GnRH neuronal function and sexual dimorphism in the threshold levels of GnRH required to preserve reproductive functions.

Biotin Enhances Testosterone Production in Mice and Their Testis-Derived Cells.

Late-onset hypogonadism, a male age-related syndrome characterized by a decline in testosterone production in the testes, is commonly treated with testosterone replacement therapy, which has adverse side effects. Therefore, an alternative treatment is highly sought. Supplementation of a high dosage of biotin, a water-soluble vitamin that functions as a coenzyme for carboxylases involved in carbohydrate, lipid, and amino acid metabolism, has been shown to influence testis functions. However, the involvement of biotin in testis steroidogenesis has not been well clarified. In this study, we examined the effect of biotin on testosterone levels in mice and testis-derived cells. In mice, intraperitoneal treatment with biotin (1.5 mg/kg body weight) enhanced testosterone levels in the serum and testes, without elevating serum levels of pituitary luteinizing hormone. To investigate the mechanism in which biotin increased the testosterone level, mice testis-derived I-10 cells were used. The cells treated with biotin increased testosterone production in a dose- and time-dependent manner. Biotin treatment elevated intracellular cyclic adenosine monophosphate levels via adenylate cyclase activation, followed by the activation of protein kinase A and testosterone production. These results suggest that biotin may have the potential to improve age-related male syndromes associated with declining testosterone production.

Novel pituitary actions of GnRH in teleost: The link between reproduction and feeding regulation.

Gonadotropin-releasing hormone (GnRH), as a vital hypothalamic neuropeptide, was a key regulator for pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the vertebrate. However, little is known about the other pituitary actions of GnRH in teleost. In the present study, two GnRH variants (namely, GnRH2 and GnRH3) and four GnRH receptors (namely, GnRHR1, GnRHR2, GnRHR3, and GnRHR4) had been isolated from grass carp. Tissue distribution displayed that GnRHR4 was more highly detected in the pituitary than the other three GnRHRs. Interestingly, ligand–receptor selectivity showed that GnRHR4 displayed a similar and high binding affinity for grass carp GnRH2 and GnRH3. Using primary culture grass carp pituitary cells as model, we found that both GnRH2 and GnRH3 could not only significantly induce pituitary reproductive hormone gene (GtHα, LHβ, FSHβ, INHBa, secretogranin-2) mRNA expression mediated by AC/PKA, PLC/IP3/PKC, and Ca2+/CaM/CaMK-II pathways but also reduce dopamine receptor 2 (DRD2) mRNA expression via the Ca2+/CaM/CaMK-II pathway. Interestingly, GnRH2 and GnRH3 could also stimulate anorexigenic peptide (POMCb, CART2, UTS1, NMBa, and NMBb) mRNA expression via AC/PKA, PLC/IP3/PKC, and Ca2+/CaM/CaMK-II pathways in grass carp pituitary cells. In addition, food intake could significantly induce brain GnRH2 mRNA expression. These results indicated that GnRH should be the coupling factor to integrate the feeding metabolism and reproduction in teleost.

Ethanolamine plasmalogens derived from scallops stimulate both follicle-stimulating hormone and luteinizing hormone secretion by bovine gonadotrophs

Brain ethanolamine plasmalogens (EPls) are the only known ligands of G-protein-coupled receptor 61, a novel receptor that stimulates follicle-stimulating hormone (FSH), but not luteinizing hormone (LH), secretion by bovine gonadotrophs. We hypothesized that the recently developed neuroprotective EPls extracted from scallop (Pecten yessoensis) (scallop EPls) could stimulate FSH secretion by gonadotrophs. To test this hypothesis, bovine gonadotrophs were cultured for 3.5 days and treated with increasing concentrations of scallop EPls. FSH secretion was stimulated by all tested concentrations of scallop EPls (P < 0.05). Surprisingly, LH secretion was stimulated by both 0.5 (P < 0.05) and 5 (P < 0.01) ng/mL of scallop EPls. To clarify the important differences between bovine brain and scallop EPls, we utilized two-dimensional liquid chromatography–mass spectrometry, which revealed 44 peaks, including 10 large peaks. Among them, eight were scallop-specific EPl molecular species, occupying approximately 58% of the total area percentage of scallop EPls. Almost all large peaks contained 4, 5, or 6 unsaturated double bonds in the carbon chain at the sn-2 position of the glycerol backbone. Our results showed that EPls from scallops, lacking pituitary glands, stimulated both FSH and LH secretion by bovine gonadotrophs.

Association of age, hormonal, and lifestyle factors with the Leydig cell biomarker INSL3 in aging men from the European Male Aging Study cohort.

BackgroundAging in men is accompanied by a broad range of symptoms, including sexual dysfunction, cognitive and musculoskeletal decline, obesity, type 2 diabetes, cardiovascular disease and hypertension, organ degeneration/failure, and increasing neoplasia, some of which are associated with declining levels of Leydig cell‐produced testosterone. High natural biological variance, together with multiple factors that can modulate circulating testosterone concentration, may influence its interpretation and clinical implications. Insulin‐like peptide 3 is a biomarker of Leydig cell function that might provide complementary information on testicular health and its downstream outcomes.ObjectivesTo characterize insulin‐like peptide 3 as a biomarker to assess gonadal status in aging men.Methods and materialsA large European multicenter (European Male Aging Study) cohort of community‐dwelling men was analyzed to determine how insulin‐like peptide 3 relates to a range of hormonal, anthropometric, and lifestyle parameters.Results and discussionInsulin‐like peptide 3 declines cross‐sectionally and longitudinally within individuals at approximately 15% per decade from age 40 years, unlike testosterone (1.9% per decade), which is partly compensated by increasing pituitary luteinizing hormone production. Importantly, lower insulin‐like peptide 3 in younger men appears to persist with aging. Multiple regression analysis shows that, unlike testosterone, insulin‐like peptide 3 is negatively dependent on luteinizing hormone and sex hormone‐binding globulin and positively dependent on follicle‐stimulating hormone, suggesting a different mechanism of gonadotropic regulation. Circulating insulin‐like peptide 3 is negatively associated with increased body mass index or waist circumference and with smoking, and unlike testosterone, it is not affected by weight loss in obese individuals. Geographic variation in mean insulin‐like peptide 3 within Europe appears to be largely explained by differences in these parameters. The results allowed the establishment of a European‐wide reference range for insulin‐like peptide 3 (95% confidence interval) adjusted for increasing age.ConclusionInsulin‐like peptide 3 is a constitutive biomarker of Leydig cell functional capacity and is a robust, reliably measurable peptide not subject to gonadotropin‐dependent short‐term regulation and within‐individual variation in testosterone.

The Effect of Air Pollutants on liver Enzymes and Pituitary Gland Hormones of Smokers and non-smokers of Oil Refinery and Gas Station Workers in Basra/Iraq

Air pollutants that originated from oil refineries and gas pump stations can have a negative effect on humanorgans, especially liver and brain. This study focuses on evaluating the pollutants from oil refinery and gasstation on workers’ health by measuring three hepatic enzymes GOT (Glutamic Oxaloacetic Transaminase),GPT (Glutamic Pyruvic Transaminase), ALP(Alkaline phosphatase) and three pituitary gland hormones LH(Luteinizing hormone), FSH (Follicle-stimulating hormone), TSH (Thyroid-stimulating hormone). Study groupswere (i) 33 males from Basra oil refinery workers including 16 smoker and 17 non-smoker (ii) 23 male from Gasstation, 11 of them were smoker while the other 12 are non-smoker (iii) 24 male local volunteers from Basra (allhad non-oil related job) as a control group, 12 smoker and 12 non-smokers. All three groups’ subjects had neitherfamily history of raspatory problems nor diabatic. The results indicated a significance decrease in FSH, LH, TSHhormones and GPT, ALP enzymes of oil refinery workers, comparing to the control group. The same trend wasalso observed among gas station workers, suggesting hepatotoxicity and alternation in pituitary hormones.Pollutants that circulating around oil industry sites can negatively impact human body especially for those whowork near these locations.

P-661 dydrogesterone as an alternative to supress LH surge in single stimulus protocols with follitropin delta

Abstract Study question Is oral dydrogesterone (DYG) 30 mg daily efficient on prevention of premature luteinizing hormone (LH) surge in ART cycles? Summary answer Oral dydrogesterone demonstrated to be as safe and effective as GnRH-ant in IVF/ICSI cycles intended to freeze-all / PGT-A, oocyte preservation and embryo banking programs What is known already The use of progesterone (PG) to inhibit pituitary LH surge during ovarian stimulation have been described over the last decades. Due to its harmful effect on the endometrium, PG suppression is mainly reserved for freeze-all cycles. Dydrogesterone (DYG), a known and safe synthetic progesterone, has been tested for this purpose based on the concept of its more selective PG receptors activity, which could reduce the inconveniences of side effects with less relevant androgenic, estrogenic, glyco or mineralocorticoid activity. Accordind to some recent work, DYG would be an effective tool both in cycles intended to freeze-all or in oocyte preservation strategies. Study design, size, duration Observational, comparative single center study, comparing the effect of DYG and gonadotropin releasing hormone (GnRH) antagonists on prevention of premature luteinizing hormone (LH) surge as well as to evaluate the number of metaphase II oocytes. From January 2019 to January 2020, 143 no age restrictions patients underwent both IVF/ICSI or oocyte preservation, all of them receiving the same single stimulus protocol with follitropin delta (Rekovelle). Participants/materials, setting, methods 92 IVF/ICSI plus 51 oocyte cryopreservation cycles underwent deltafollitropin (Rekovelle®, Ferring Pharmaceuticals) in a fixed daily and individualized SC-dose. Clinical decision led to a GnRH-antagonist (CTA-Cetrorelix acetate, Cetrotide®, Merck) 0,25 mg/d initiated in a flexible schedule in presence of one follicle ≥14 mm and continued throughout the stimulation period (48 cycles) or dydrogesterone (DYG), 10mg 8/8 hours (Duphaston®, Abbott) combined to gonadotrophin from the beginning of stimulation until the day after the trigger (95 cycles). Main results and the role of chance DYG-group had a mean age significantly higher (37.8 x 35.8-p 0.002) but there were no differences in mean parameters of BMI (24.08 x 24.81), days of stimulation (9.95 x 10.08), AMH (2.30 x 2.52), AFC (14.6 x 16.2). In the same way, no differences were observed between follicles 15 mm to 18 mm (3.06 x 3.68) and ≥ 18 mm (4.56 x 3.9), with a tendency for a greater number of larger follicles in the DYG-group. Metaphase II oocytes (7.48 x 7.33) was similar in both groups. One patient from each group experienced a premature LH surge (3.54 x 3.06) and one case in the DYG-group had no oocyte in a single 20mm aspirated follicle. There happened no cancelling. No patients experienced moderate to severe ovarian hyper stimulation syndrome, even when AMH&amp;gt;3 ng/mL. Cancelling criteria: no follicles with a diameter 17 mm by day 15. Oocyte retrieval took place 36 hours after trigging. Primary outcome was the incidence of premature LH surge. Secondary outcomes included follicles ≥ 15 mm and &amp;lt; 18 mm and ≥ 18 mm on hCG day, metaphase II oocytes, number of cancelled cycles and OHSS symptoms. Statistics were performed by Mann-Whitney test. Limitations, reasons for caution The main limitation point is the small number of patients. Despite having relative experience with the use of DYG, in this work we limited the sample to consider only one type of stimulus protocol, making the groups more homogeneous for the analysis. Wider implications of the findings Dydrogesterone is as effective as GnRH-ant in reducing premature LH surge. It can be considered for IVF/ICSI cycles intended to freeze-all / PGT-A, oocyte preservation and for embryo banking strategies, representing lower costs in these cases. Trial registration number not applicable

Outcomes of a GnRH Agonist Trigger Following a GnRH Antagonist or Flexible Progestin-Primed Ovarian Stimulation Cycle.

A suggested explanation for the pituitary-suppressive effects of progestin-primed ovarian stimulation cycles (PPOS) is pituitary luteinizing hormone (LH) depletion with progestin exposure during the follicular phase. The GnRH agonist (GnRHa) trigger releases endogenous LH from the pituitary, and if the LH depletion theory is correct, the response to the agonist trigger would be dampened in PPOS cycles. In this study, we compared the performance of the GnRHa trigger after PPOS and GnRH antagonist ovarian stimulation cycles. All women who underwent ovarian stimulation with the GnRH antagonist or flexible PPOS (fPPOS) and received a GnRH agonist trigger were eligible for inclusion. Outcomes included number of metaphase-II (MII) oocytes retrieved per cycle, rates of empty follicle syndrome, maturation, fertilization, blastulation, and cumulative clinical pregnancy per stimulation cycle. During the screening period, there were 166 antagonists and 58 fPPOS cycles triggered with a GnRH agonist. Groups were matched for potential confounders using propensity score matching. Progestin-downregulated cycles had 19% high mature oocyte yield (median: 14 vs. 19 MII oocytes, P = 0.03). Cumulative ongoing pregnancy or live birth rates were estimated after matching for transferred embryo count, and rates were similar between GnRH antagonist and fPPOS group (57.0% vs. 62.1%, P = 0.68). However, the number of remaining blastocysts was higher in the fPPOS group (median: 5.0 vs. 6.0, P < 0.001). LH levels were higher in fPPOS cycles compared to GnRH antagonist cycles up to the trigger day (P < 0.001). After the GnRHa trigger, fPPOS cycles were associated with a steeper LH surge compared with antagonist cycles (P = 0.02). Higher endogenous gonadotropin levels through the stimulation period and an LH surge of higher magnitude following a GnRHa trigger suggest a milder pituitary suppression by fPPOS, which needs to be confirmed in larger samples. It appears that progestins do not deplete pituitary LH reserves and a GnRHa trigger is usable after PPOS in women with high ovarian reserve.

Pituitary luteinizing hormone synthesis starts in aromatase (cyp19a1b)-positive cells expressing esr1 and esr2b at the onset of puberty in Takifugu rubripes (fugu)

Unlike mammals, teleost fish have high aromatase activity (AA) in the pituitary. However, the cells responsible for oestradiol synthesis and the local physiological roles of this hormone remain unclear. Hence, we investigated the effects of age and development on steroidogenic activity, mRNA expression, and cyp19a1b localization in the pituitary gland of the Japanese pufferfish Takifugu rubripes. Under aquaculture conditions, AA was highest after puberty, and the mRNA expression levels of cyp19a1b and the oestrogen receptors esr1 and 2b and the level of serum testosterone (T) were significantly increased after puberty compared with the other developmental stages in male and female pufferfish. Immunohistochemistry using multiple antibodies and in situ hybridization analysis revealed that Cyp19a1b colocalizes with luteinizing hormone (LH) in pituitary cells. Furthermore, Esr1 was localized in the nuclei of all hormone-producing cells, whereas Esr2b was localized only in the nuclei of Cyp19- and LH-positive cells. The administration of an aromatizable androgen (T) or oestrogen (E2) to reproductively inactive females induced LH synthesis in vivo. We prepared spheroids from pituitary cells to investigate the role of local E2 in LH synthesis in vitro. Immunohistochemical analysis of spheroids showed that T-induced LH synthesis could be blocked by an aromatase inhibitor and/or an ER antagonist but not an AR antagonist. Taken together, these findings suggest that LH synthesis is initiated in cyp19a1b-, esr1-, and esr2b-expressing cells at the onset of puberty under the control of steroidal feedback, and both feedback and local oestrogen may be involved in controlling LH synthesis in these cells.

Mechanism of Action of an Environmentally Relevant Organochlorine Mixture in Repressing Steroid Hormone Biosynthesis in Leydig Cells.

Within Leydig cells, steroidogenesis is induced by the pituitary luteinizing hormone (LH). The binding of LH to its receptor increases cAMP production, which then activates the expression of genes involved in testosterone biosynthesis. One of these genes codes for the steroidogenic acute regulatory (STAR) protein. STAR is part of a complex that shuttles cholesterol, the precursor of all steroid hormones, through the mitochondrial membrane where steroidogenesis is initiated. Organochlorine chemicals (OCs) are environmental persistent organic pollutants that are found at high concentrations in Arctic areas. OCs are known to affect male reproductive health by decreasing semen quality in different species, including humans. We previously showed that an environmentally relevant mixture of OCs found in Northern Quebec disrupts steroidogenesis by decreasing STAR protein levels without affecting the transcription of the gene. We hypothesized that OCs might affect STAR protein stability. To test this, MA-10 Leydig cell lines were incubated for 6 h with vehicle or the OCs mixture in the presence or absence of 8Br-cAMP with or without MG132, an inhibitor of protein degradation. We found that MG132 prevented the OC-mediated decrease in STAR protein levels following 8Br-cAMP stimulation. However, progesterone production was still decreased by the OC mixture, even in the presence of MG132. This suggested that proteins involved in steroid hormone production in addition to STAR are also affected by the OC mixture. To identify these proteins, a whole cell approach was used and total proteins from MA-10 Leydig cells exposed to the OC mixture with or without stimulation with 8Br-cAMP were analyzed by 2D SDS-PAGE and LC-MS/MS. Bioinformatics analyses revealed that several proteins involved in numerous biological processes are affected by the OC mixture, including proteins involved in mitochondrial transport, lipid metabolism, and steroidogenesis.

Pituitary Luteinizing Hormone Analysis for Estimation of Time Passed Since Death: Biochemical Study (An Experimental Study)

Pituitary Luteinizing Hormone Analysis for Estimation of Time Passed Since Death: Biochemical Study (An Experimental Study)

Uterine HOXA11 antisense long non-coding RNA prevents decidualization: A new pathway-regulating pregnancy

To achieve a successful pregnancy, coordinated development of the embryo and uterine endometrium are normally archived by coupling ovulation to progesterone production. A surge of pituitary luteinizing hormone triggers the release of oocytes and simultaneously initiates the conversion of the ovarian follicle to the corpus luteum, which produces large quantities of progesterone. Progesterone, in turn, drives endometrial differentiation, also known as decidualization. The decidualized endometrium is briefly receptive to the developing embryo, allowing the embryo to attach and implant in the uterine endometrium, thus establishing the early pregnancy.

Ovarian Sensitivity Decreased Significantly in Patients With Insulin Resistance Undergoing in vitro Fertilization and Embryo Transfer.

Ovarian sensitivity could affect the outcome of in vitro fertilization and embryo transfer (IVF-ET). The objective of this study was to explore the relationship between the ovarian sensitivity index (OSI) and traditional ovarian response makers and observe the relationship between OSI and insulin resistance (IR). The patients enrolled in this study included 131 patients with polycystic ovary syndrome (PCOS) with IR (PCOS-IR), 52 patients with PCOS without IR (PCOS-N), 164 patients with control with IR (control-IR), 133 patients with control without IR (control-N), 295 patients with IR, 184 patients with non-IR, 183 patients with PCOS, and 297 patients with control (patients with non-PCOS). All patients received standard long protocol or the gonadotropin-releasing hormone (GnRH) antagonist protocol to induce follicular development. The two protocols downregulated the pituitary function or blocked the pituitary luteinizing hormone (LH) secretion with a GnRH antagonist. Both protocols can block premature LH surges because premature luteinization is not conducive to follicular development. All patients underwent IVF or intracytoplasmic sperm injection (ICSI). Embryo transfer was carried out according to the specific situation of each patient. The OSI was significantly reduced in patients with IR. The OSI had a significant positive relationship with anti-Müllerian hormone (AMH), antral follicle count (AFC), basal LH/follicle-stimulating hormone (FSH), dominant follicle number on trigger day, retrieved oocytes, embryo number, and high-quality embryo number. OSI had a significant negative relationship with age, body mass index (BMI), basal FSH, initial dose of Gn, and total dose of Gn. The receiver operating characteristic (ROC) curve of OSI demonstrated a better accuracy in distinguishing patients with positive pregnancy and clinical pregnancy, with an area under the curve (AUC) of 0.662 (95% CI, 0.598–0.727) and 0.636 (95% CI, 0.577–0.695), respectively. Patients could get a higher rate of dominant follicle count (p < 0.0001) through the treatment of standard long protocol when compared with GnRH antagonist protocol. The OSI has a significant correlation with traditional ovarian response markers and could be a good predictor of positive pregnancy and clinical pregnancy for patients with IR.