Norepinephrine Neurons in the Nucleus of the Solitary Tract Suppress Luteinizing Hormone Secretion in Female Mice.

Stress impairs fertility, at least in part, via inhibition of gonadotropin secretion. Luteinizing hormone (LH) is an important gonadotropin that is released in a pulsatile pattern in males and in females throughout the majority of the ovarian cycle. Several models of stress, including acute metabolic stress, suppress LH pulses via inhibition of neurons in the arcuate nucleus of the hypothalamus that coexpress kisspeptin, neurokinin B, and dynorphin (termed KNDy cells) which form the pulse generator. The mechanism for inhibition of KNDy neurons during stress, however, remains a significant outstanding question. Here, we investigated a population of catecholamine neurons in the nucleus of the solitary tract (NTS), marked by expression of the enzyme dopamine beta-hydroxylase (DBH), in female mice. First, we found that a subpopulation of DBH neurons in the NTS is activated (express c-Fos) during metabolic stress. Then, using chemogenetics, we determined that activation of these cells is sufficient to suppress LH pulses, augment corticosterone secretion, and induce sickness-like behavior. In subsequent studies, we identified evidence for suppression of KNDy cells (rather than downstream signaling pathways) and determined that the suppression of LH pulses was not dependent on the acute rise in glucocorticoids. Together these data support the hypothesis that DBH cells in the NTS are important for regulation of neuroendocrine and behavioral responses to stress.

An i-motif-regulated enhancer, eRNA and adjacent lncRNA affect Lhb expression through distinct mechanisms in a sex-specific context.

Genome-wide studies have demonstrated regulatory roles for diverse non-coding elements, but their precise and interrelated functions have often remained enigmatic. Addressing the need for mechanistic insight, we studied their roles in expression of Lhb which encodes the pituitary gonadotropic hormone that controls reproduction. We identified a bi-directional enhancer in gonadotrope-specific open chromatin, whose functional eRNA (eRNA2) supports permissive chromatin at the Lhb locus. The central untranscribed region of the enhancer contains an iMotif (iM), and is bound by Hmgb2 which stabilizes the iM and directs transcription specifically towards the functional eRNA2. A distinct downstream lncRNA, associated with an inducible G-quadruplex (G4) and iM, also facilitates Lhb expression, following its splicing in situ. GnRH activates Lhb transcription and increased levels of all three RNAs, eRNA2 showing the highest response, while estradiol, which inhibits Lhb, repressed levels of eRNA2 and the lncRNA. The levels of these regulatory RNAs and Lhb mRNA correlate highly in female mice, though strikingly not in males, suggesting a female-specific function. Our findings, which shed new light on the workings of non-coding elements and non-canonical DNA structures, reveal novel mechanisms regulating transcription which have implications not only in the central control of reproduction but also for other inducible genes.

In vivo imaging of the GnRH pulse generator reveals a temporal order of neuronal activation and synchronization during each pulse.

A hypothalamic pulse generator located in the arcuate nucleus controls episodic release of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) and is essential for reproduction. Recent evidence suggests this generator is composed of arcuate "KNDy" cells, the abbreviation based on coexpression of kisspeptin, neurokinin B, and dynorphin. However, direct visual evidence of KNDy neuron activity at a single-cell level during a pulse is lacking. Here, we use in vivo calcium imaging in freely moving female mice to show that individual KNDy neurons are synchronously activated in an episodic manner, and these synchronized episodes always precede LH pulses. Furthermore, synchronization among KNDy cells occurs in a temporal order, with some subsets of KNDy cells serving as "leaders" and others as "followers" during each synchronized episode. These results reveal an unsuspected temporal organization of activation and synchronization within the GnRH pulse generator, suggesting that different subsets of KNDy neurons are activated at pulse onset than afterward during maintenance and eventual termination of each pulse. Further studies to distinguish KNDy "leader" from "follower" cells is likely to have important clinical significance, since regulation of pulsatile GnRH secretion is essential for normal reproduction and disrupted in pathological conditions such as polycystic ovary syndrome and hypothalamic amenorrhea.

Phosphatases modified by LH signaling in ovarian follicles: testing their role in regulating the NPR2 guanylyl cyclase†.

In response to luteinizing hormone (LH), multiple proteins in rat and mouse granulosa cells are rapidly dephosphorylated, but the responsible phosphatases remain to be identified. Because the phosphorylation state of phosphatases can regulate their interaction with substrates, we searched for phosphatases that might function in LH signaling by using quantitative mass spectrometry. We identified all proteins in rat ovarian follicles whose phosphorylation state changed detectably in response to a 30-min exposure to LH, and within this list, identified protein phosphatases or phosphatase regulatory subunits that showed changes in phosphorylation. Phosphatases in the phosphoprotein phosphatase (PPP) family were of particular interest because of their requirement for dephosphorylating the natriuretic peptide receptor 2 (NPR2) guanylyl cyclase in the granulosa cells, which triggers oocyte meiotic resumption. Among the PPP family regulatory subunits, PPP1R12A and PPP2R5D showed the largest increases in phosphorylation, with 4-10 fold increases in signal intensity on several sites. Although follicles from mice in which these phosphorylations were prevented by serine-to-alanine mutations in either Ppp1r12a or Ppp2r5d showed normal LH-induced NPR2 dephosphorylation, these regulatory subunits and others could act redundantly to dephosphorylate NPR2. Our identification of phosphatases and other proteins whose phosphorylation state is rapidly modified by LH provides clues about multiple signaling pathways in ovarian follicles.

The effect of NK3-Saporin injection within the arcuate nucleus on puberty, the LH surge, and the response to Senktide in female sheep†.

The timing of puberty onset is reliant on increased gonadotropin-releasing hormone (GnRH). This elicits a corresponding increase in luteinizing hormone (LH) due to a lessening of sensitivity to the inhibitory actions of estradiol (E2). The mechanisms underlying the increase in GnRH release likely involve a subset of neurons within the arcuate (ARC) nucleus of the hypothalamus that contain kisspeptin, neurokinin B (NKB), and dynorphin (KNDy neurons). We aimed to determine if KNDy neurons in female sheep are critical for: timely puberty onset; the LH surge; and the response to an intravenous injection of the neurokinin-3 receptor (NK3R) agonist, senktide. Prepubertal ewes received injections aimed at the ARC containing blank-saporin (control, n = 5) or NK3-saporin (NK3-SAP, n = 6) to ablate neurons expressing NK3R. Blood samples taken 3/week for 65 days following surgery were assessed for progesterone to determine onset of puberty. Control ewes exhibited onset of puberty at 33.2 ± 3.9 days post sampling initiation, whereas 5/6 NK3-SAP treated ewes didn't display an increase in progesterone. After an artificial LH surge protocol, surge amplitude was lower in NK3-SAP ewes. Finally, ewes were treated with senktide to determine if an LH response was elicited. LH pulses were evident in both groups in the absence of injections, but the response to senktide vs saline was similar between groups. These results show that KNDy cells are necessary for timely puberty onset and for full expresson of the LH surge. The occurrence of LH pulses in NK3-SAP treated ewes may indicate a recovery from an apulsatile state.

Luteinizing hormone stimulates ingression of mural granulosa cells within the mouse preovulatory follicle†.

Luteinizing hormone (LH) induces ovulation by acting on its receptors in the mural granulosa cells that surround a mammalian oocyte in an ovarian follicle. However, much remains unknown about how activation of the LH receptor modifies the structure of the follicle such that the oocyte is released and the follicle remnants are transformed into the corpus luteum. The present study shows that the preovulatory surge of LH stimulates LH receptor-expressing granulosa cells, initially located almost entirely in the outer layers of the mural granulosa, to rapidly extend inwards, intercalating between other cells. The cellular ingression begins within 30 min of the peak of the LH surge, and the proportion of LH receptor-expressing cell bodies in the inner half of the mural granulosa layer increases until the time of ovulation, which occurs at about 10 h after the LH peak. During this time, many of the initially flask-shaped cells appear to detach from the basal lamina, acquiring a rounder shape with multiple filipodia. Starting at about 4 h after the LH peak, the mural granulosa layer at the apical surface of the follicle where ovulation will occur begins to thin, and the basolateral surface develops invaginations and constrictions. Our findings raise the question of whether LH stimulation of granulosa cell ingression may contribute to these changes in the follicular structure that enable ovulation.

The effects of short-term and long-term phthalate exposures on ovarian follicle growth dynamics and hormone levels in female mice†.

Di(2-ethylhexyl) phthalate and diisononyl phthalate are widely used as plasticizers in polyvinyl chloride products. Short-term exposures to phthalates affect hormone levels, ovarian follicle populations, and ovarian gene expression. However, limited data exist regarding the effects of long-term exposure to phthalates on reproductive functions. Thus, this study tested the hypothesis that short-term and long-term exposure to di(2-ethylhexyl) phthalate or diisononyl phthalate disrupts follicle dynamics, ovarian and pituitary gene expression, and hormone levels in female mice. Adult CD-1 female mice were exposed to vehicle, di(2-ethylhexyl) phthalate, or diisononyl phthalate (0.15 ppm, 1.5 ppm, or 1500 ppm) via the chow for 1 or 6 months. Short-term exposure to di(2-ethylhexyl) phthalate (0.15 ppm) and diisononyl phthalate (1.5 ppm) decreased serum follicle-stimulating hormone levels compared to control. Long-term exposure to di(2-ethylhexyl) phthalate and diisononyl phthalate (1500 ppm) increased the percentage of primordial follicles and decreased the percentages of preantral and antral follicles compared to control. Both phthalates increased follicle-stimulating hormone levels (di(2-ethylhexyl) phthalate at 1500 ppm; diisononyl phthalate at 1.5 ppm) and decreased luteinizing hormone levels (di(2-ethylhexyl) phthalate at 0.15 and 1.5 ppm; diisononyl phthalate at 1.5 ppm and 1500 ppm) compared to control. Furthermore, both phthalates altered the expression of pituitary gonadotropin subunit genes (Cga, Fshb, and Lhb) and a transcription factor (Nr5a1) that regulates gonadotropin synthesis. These data indicate that long-term exposure to di(2-ethylhexyl) phthalate and diisononyl phthalate alters follicle growth dynamics in the ovary and the expression of gonadotropin subunit genes in the pituitary and consequently luteinizing hormone and follicle-stimulating hormone synthesis.

Chronic estradiol exposure suppresses luteinizing hormone surge without affecting kisspeptin neurons and estrogen receptor alpha in anteroventral periventricular nucleus†.

Mammalian ovulation is induced by a luteinizing hormone surge, which is triggered by elevated plasma estrogen levels; however, chronic exposure to high levels of estradiol is known to inhibit luteinizing hormone secretion. In the present study, we hypothesized that the inhibition of the luteinizing hormone surge by chronic estradiol exposure is due to the downregulation of the estrogen receptor alpha in kisspeptin neurons at hypothalamic anteroventral periventricular nucleus, which is known as the gonadotropin-releasing hormone/luteinizing hormone surge generator. Animals exposed to estradiol for 2 days showed an luteinizing hormone surge, whereas those exposed for 14 days showed a significant suppression of luteinizing hormone. Chronic estradiol exposure did not affect the number of kisspeptin neurons and the percentage of kisspeptin neurons with estrogen receptor alpha or c-Fos in anteroventral periventricular nucleus, but it did affect the number of kisspeptin neurons in arcuate nucleus. Furthermore, chronic estradiol exposure did not affect gonadotropin-releasing hormone neurons. In the pituitary, 14-day estradiol exposure significantly reduced the expression of Lhb mRNA and LHß-immunoreactive areas. Gonadotropin-releasing hormone-induced luteinizing hormone release was also reduced significantly by 14-day estradiol exposure. We revealed that the suppression of an luteinizing hormone surge by chronic estradiol exposure was induced in association with the significant reduction in kisspeptin neurons in arcuate nucleus, luteinizing hormone expression in the pituitary, and pituitary responsiveness to gonadotropin-releasing hormone, and this was not caused by changes in the estrogen receptor alpha-expressing kisspeptin neurons in anteroventral periventricular nucleus and gonadotropin-releasing hormone neurons, which are responsible for estradiol positive feedback.

Quantification of urinary gonadotropins by specific assays may improve the evaluation of sex-specific hormonal changes in early infancy.

OBJECTIVE: The aim of this study was to investigate the feasibility of different gonadotropin assays for determining total and intact luteinizing hormone (LH), and follicle-stimulating hormone (FSH) immunoreactivity in urine (U-LH-ir and U-FSH-ir, respectively) during early infancy. DESIGN, PATIENTS AND MEASUREMENTS: Morning urine samples were obtained from 31 infants, aged between 0 and 6 months, to study the age-related course of urinary gonadotropins. Additionally, we investigated bi-hourly urine samples of a 5-day-old male neonate for 24 h to observe the course of urinary gonadotropins during a daily cycle. We employed different immunofluorometric assays for measuring total and intact U-LH-ir, and U-FSH-ir. RESULTS: In neonates up to 21 days of age, the U-LH-ir levels measured by the regular LH assay (also detecting hCG) were significantly higher than those determined by the total (specific) LH assays (p = .004). U-FSH-ir was higher in girls than boys during both the first and the next 5 months (p = .02 and p < .001, respectively), whereas total U-LH-ir was higher in boys until 6 months of age (p < .001). Total U-LH-ir/U-FSH-ir ratio was significantly higher in boys than girls across the first half-year (p < .001). CONCLUSIONS: The assessment of total U-LH-ir and U-FSH-ir, and their respective ratio constitutes a noninvasive, practical and scalable tool to investigate sex-specific changes during early infancy, with the ratio being significantly higher in boys than girls. Only highly specific LH assays detecting beta-subunit and its core fragment in addition to intact LH should be used for determining U-LH-ir in the neonatal period to avoid potential cross-reactivity with hCG of placental origin.

The relationship between male and female endogenous reproductive hormones levels and subjective cognitive decline score: A cross-sectional analysis of the Pingyin cohort study.

OBJECTIVE: Reproductive hormones might impact disease course in cognitive decline. We examined the association between male and female endogenous reproductive hormones and subjective cognitive decline (SCD) score. DESIGN, PATIENTS AND MEASUREMENTS: A cross-sectional study design was used with baseline data from the Pingyin cohort study, involving 1943 participants aged 45-70 years. Oestrogen (E2), testosterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH) were measured in females and E2 and testosterone were measured in males. We categorised hormones into three levels of low, intermediate and high level. The 9-item subjective cognitive decline questionnaire (SCD-Q9) scores were collected to assess the symptoms of SCD. Multivariable logistic regression models were used to estimate odds ratios (ORs) and 95% confidence interval (CI) between categorised hormone levels and SCD status. Multivariable linear regression models were also used. RESULTS: Overall, 1943 participants were involved and 1285 (66.1%) were female. The mean age at baseline was 59.1 (standard deviation 7.1) years. Women with high testosterone levels had a higher probability of having SCD compared with those with low testosterone levels (OR 1.43, 95% CI 1.01-2.05). Men with a high level of testosterone (0.59, 0.35-0.98) and high testosterone/E2 ratio (0.55, 0.33-0.90) were related to decreased chances of having SCD. Each one-unit increase of testosterone was linked to reduced SCD score in males [(ß: -.029, 95% CI (-0.052, -0.007)]. CONCLUSION: There was sex-specific relationship between hormone levels and SCD abnormal. Those with higher testosterone levels in females may increase likelihood of experiencing SCD. Males with higher testosterone levels and higher testosterone/E2 ratio may be associated with reduced likelihood of SCD. The roles of endogenous reproductive hormone levels and their dynamic changes in cognitive function need further investigation.

Effect of LH level on HCG trigger day on clinical outcomes in patients with diminished ovarian reserve undergoing GnRH-antagonist protocol.

RESEARCH QUESTION: Does luteinizing hormone (LH) levels on human chorionic gonadotropin (HCG) trigger day (LHHCG) affect the clinical outcomes of patients with diminished ovarian reserve (DOR) undergoing gonadotropin-releasing hormone antagonist (GnRH-ant) protocol? METHODS: Retrospective analysis fresh embryo transfer cycles of DOR patients who underwent GnRH-ant protocol from August 2019 to June 2023. The participants were divided into different groups according to LHHCG level and age. The clinical data and outcomes were compared between groups. RESULTS: In patients with DOR, the HCG positive rate (59.3% versus 39.8%, P = 0.005), embryo implantation rate (34.5% versus 19.7%, P = 0.002), clinical pregnancy rate (49.2% versus 28.4%, P = 0.003), live birth rate (41.5% versus 22.7%, P = 0.005) in LHHCG < 2.58 IU/L group were significantly higher than LHHCG ≥ 2.58 IU/L group. There was no significant correlation between LHHCG level and clinical pregnancy in POSEIDON group 3. In POSEIDON group 4, the HCG positive rate (52.8% versus 27.0%, P = 0.015), embryo implantation rate (29.2% versus 13.3%, P = 0.023), clinical pregnancy rate (45.3% versus 18.9%, P = 0.010) in LHHCG < 3.14 IU/L group were significantly higher than LHHCG ≥ 3.14 IU/L group. Logistic regression analysis indicated that LHHCG level was an independent influencing factor for clinical pregnancy in POSEIDON group 4 patients (OR = 3.831, 95% CI: 1.379-10.643, P < 0.05). CONCLUSIONS: LHHCG level is an independent factor affecting pregnancy outcome of fresh embryo transfer in DOR patients undergoing GnRH-ant protocol, especially for advanced-aged women. LHHCG had a high predictive value for POSEIDON group 4 patients, and LHHCG ≥ 3.14 IU/L predicts poor pregnancy outcomes.

Development of a reporter gene-based assay for the bioactivity determination of rhLH pharmaceutical products.

To establish an in vitro biological activity detection method for luteinizing hormone (LH), the hLHCGR-CREB-HEK293 cell line was constructed to stably express human luteinizing hormone/chorionic gonadotropin receptor (hLHCGR). After optimization, the rhLH starting working concentration was 800 mIU/mL with 4-fold serial dilutions, 10 concentrations and an incubation time of 5 h. The method was confirmed to be highly specific, with good accuracy, precision and linearity, meeting the needs of process research and release testing, and can be used as a routine detection method for LH biological activity. With the increasing demand for research and development of rhLH biologically similar drugs, establishing a stable and simple activity assay method to evaluate the biological activity of rhLH can provide technical support for quality control of rhLH products and powerful tools for comparability research of similar products.

Pubertal luteinizing hormone levels in children with chronic kidney disease and association with change in glomerular filtration rate.

BACKGROUND: Children with chronic kidney disease (CKD) are at risk for abnormalities in pubertal development. We aimed to describe the timing of pubertal onset by luteinizing hormone (LH) levels and the association between hormonal onset of puberty with changes in GFR. METHODS: Data from the Chronic Kidney Disease in Children (CKiD) study were collected prospectively. GFR was estimated at annual visits and measured by iohexol clearance every other year. LH was measured from stored repository serum samples in a nested sample of 124 participants. Hormonal onset of puberty was defined as LH level greater than or equal to 0.3 IU/L. A mixed effects model with random intercepts and slopes was used to compare the slope of decline of GFR before and after hormonal onset of puberty. The model was adjusted for age, glomerular disease diagnosis, baseline proteinuria on the log scale, and BMI. RESULTS: Median age at hormonal onset of puberty was 9.9 years (IQR 8.1, 11.9) in girls and 10.2 years (IQR 9.2, 11.0) in boys. The mixed effects model showed faster decline in both estimated GFR and measured GFR in boys after hormonal onset of puberty (p < 0.001), and a similar but attenuated accelerated estimated GFR decline was observed for girls with no difference for measured GFR. CONCLUSIONS: LH levels in the post-pubertal range were observed prior to clinical manifestations of puberty in children with CKD. Hormonal onset of puberty was associated with faster decline in GFR, particularly among boys with CKD.

Functional characterization of follicle-stimulating hormone and luteinizing hormone receptors in cloudy catshark, Scyliorhinus torazame.

The follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) in cloudy catshark were cloned, and recombinant FSHR and LHR were expressed for characterization. Ventral lobe extract (VLE) from the pituitary contains homologous FSH and LH, and it stimulated the cAMP signaling of FSHR and LHR dose-dependently. Two transcript variants of LHR (LHR-L with exon 10 and LHR-S without) were identified, and LHR-S was the dominant form with higher basal cAMP activity without VLE stimulation. Among various developmental stages of follicles, FSHR expression was mainly associated with the pre-vitellogenic and early white follicles. When follicles were recruited into vitellogenesis, the expression of FSHR decreased while of LHR was upregulated reciprocally, suggesting that LHR may also be responsible for the control of vitellogenesis in chondrichthyans. The expression of LHR-L was upregulated among maturing follicles before ovulation, indicating LHR-L could have a specific role in receiving the LH surge signal for final maturation. Plasma LH-like activity was transiently increased prior to the progesterone (P4)-surge and testosterone-drop at the beginning of P4-phase, supporting a pituitary control of follicle-maturation via LH signaling in chondrichthyans. The expression of follicular LHR was downregulated during the P4-phase when LH-like activity was high, indicating that the LH-dependent downregulation of LHR is conserved in chondrichthyans as it is in other vertebrate lineages. (213 words).

In vivo effect of recombinant Fsh and Lh administered to meagre (Argyrosomus regius) at the initial stages of sex differentiation.

Recombinant gonadotropins, follicle stimulating (rFsh) and luteinizing hormone (rLh), offer the potential to induce gametogenesis in prepubertal fish. This study aimed to determine the in vivo effect of the administration of Argyrosomus regius rFsh and rLh on the reproductive development of prepubertal meagre juveniles at the initial stages of sexual differentiation. Juvenile meagre, 9-months old with mean weight of 219 ± 3.9 g (mean ± SEM) were randomly distributed into nine groups (n = 8 per group). Experimental groups were treated weekly with an acute injection of either rFsh or rLh. Control groups were injected with saline solution. In a 3-week experiment, different groups were administered with different doses 6, 12 or 18 µg kg-1 of rFsh or rLh or saline solution. In a 6-week experiment a group was administered with 12 µg kg-1 of rFsh and a second group with saline solution. The fish were held in a single 10 m3 tank with natural photoperiod (Feb. - March) and temperature 16.1 ± 0.4 °C. At the start of the experiment (n = 8) and at the end of the 3-week experiment, fish were blood sampled and sacrificed. Blood was analysed for 17ß-estradiol (E2) and 11-ketotestosterone (11-KT). Gonads and liver were dissected and weighed. Gonads were fixed in Bouins solution and processed for histological analysis. Juvenile meagre at the start of the experiment were in the initial stages of sexual differentiation, indicated by the presence of the ovarian cavity or testes duct that was surrounded by undifferentiated embryonic germ stem cells and somatic cells. At the end of the 3-week experiment, there was no significant difference in gonadosomatic index (GSI) amongst control (initial and saline treated) and the experimental groups. After three weeks of application of rFsh, rLh or saline all fish presented a similar gonadal structure as at the start of the experiment. However, the incidence of sporadic developing germ cells (principally spermatogonia, spermatocytes, spermatids, but also perinucleolar stage oocytes) generally increased in rGth treated meagre. A mean of 44 % of meagre treated with rFsh or rLh presented sporadic isolated developing germ cells, mainly male cells. Plasma steroid levels of E2 decreased significantly from the start of the experiments to the end. At the end of the experiments there were no differences in plasma E2 amongst Control fish and rGth treated fish. Plasma 11-KT showed no change from the start of the experiment to week 3. However, a significant increase was observed in a proportion of the rFsh group after six weeks of treatment compared to the start of the experiment and the saline control group on week 6. The application of rFsh or rLh to meagre at the initial stages of sex differentiation did not stimulate steroid production until week six (11-KT) and had a limited, but evident effect on the development of sporadic isolated germ cells. However, we conclude that rGth, rFsh or rLh did not stimulate large developmental changes in sexually undifferentiated meagre gonads.

Measurement of luteinizing hormone surge in vaginal discharge: a potential biomarker that enables simple, non-invasive prediction of the periovulatory period.

BACKGROUND: Predicting the periovulatory period is very important for conception. Current approaches to predicting the periovulatory period include monitoring of basal body temperature and urine luteinizing hormone (LH) concentration; however, these methods are time-consuming. Here, we examined the potential of using vaginal discharge (VD) as a non-invasive means of sample collection for determining the LH surge that indicates ovulation. METHODS: Urine and VD samples were collected from 35 healthy women aged 20-39 years. VD samples were collected with panty liners to reduce the burden on participants. Daily first urine samples and used panty liners were collected from the 10th through 19th days of the menstrual cycle. Urine and VD LH (uLH and vLH) levels in the samples were measured by enzyme-linked immunosorbent assay. Measured vLH baseline and first surge values were analyzed using Student's t-test and ROC curves. RESULTS: Samples for a total of 55 menstrual cycles were collected. We used uLH surge to establish the date of ovulation. uLH surges were observed in 49 cycles, 34 of which had corresponding VD samples that qualified for measurement. Five cycles were excluded due to a lack of vLH data. In the remaining 29 cycles, the vLH surge appeared within the fertile window 90% of the time, and the sensitivity and specificity of the test were 86% and 83%, respectively. CONCLUSIONS: VD has potential for use as a sample for predicting the periovulatory period by measuring LH content.

Central δ/κ opioid receptor signaling pathways mediate chronic and/or acute suckling-induced LH suppression in rats during late lactation.

In mammals, secretion of tonic (pulsatile) gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) is often suppressed during lactation. Suppression of GnRH/LH pulses in lactating dams is assumed to be caused by suckling stimuli and a chronic negative energy balance due to milk production. The present study aimed to investigate whether the central enkephalin-δ opioid receptor (DOR) signaling mediated the suppression of LH secretion by acute suckling stimuli and/or chronic negative energy balance due to milk production in rats during late lactation when dams were under a heavy energy demand. On postpartum day 16, the number of Penk (enkephalin mRNA)-expressing cells in the arcuate nucleus was significantly higher in lactating rats than in non-lactating control rats. Pulsatile LH secretion was suppressed in rats with chronic suckling or acute 1-h suckling stimuli 6 h after pup removal on day 16 of lactation. Central DOR antagonism significantly increased the mean LH concentrations and the baseline of LH pulses in rats with chronic suckling but not with acute suckling stimuli on day 16 of lactation. Besides, central κ opioid receptor (KOR) antagonism increased the amplitude of LH pulses in rats with the acute suckling stimuli on day 16 of lactation. These results suggest that central DOR signaling mediates the suppression of LH secretion caused by a negative energy balance in rats receiving chronic suckling during late lactation. On the other hand, central KOR signaling likely mediates acute suckling stimuli-induced suppression of LH secretion in rats during late lactation.

Clinical parameters that predict a premature LH rise in patients undergoing ovarian stimulation for IVF.

Background: Normal reproductive function requires adequate regulation of follicle stimulating hormone (FSH) and luteinizing hormone (LH) secretion. During ovarian stimulation for in-vitro fertilization (IVF), some patients will demonstrate an early rise in LH despite being treated with a gonadotropin releasing-hormone (GnRH) antagonist, sometimes necessitating cycle cancellation. Previous studies have demonstrated a possible link between a premature LH rise with ovarian response to gonadotropins. We sought to determine what clinical parameters can predict this premature LH rise and their relative contribution. Methods: A retrospective study of 382 patients who underwent IVF treatment at Rambam Medical Center. The patients were stratified into age groups. A model predicting premature LH rise based on clinical and demographic parameters was developed using both multiple linear regression and a machine-learning-based algorithm. Results: LH rise was defined as the difference between pre-trigger and basal LH levels. The clinical parameters that significantly predicted an LH rise were patient age, BMI, LH levels at stimulation outset, LH levels on day of antagonist administration, and total number of stimulation days. Importantly, when analyzing the data of specific age groups, the model's prediction was strongest in young patients (age 25-30 years, R2 = 0.88, p < .001) and weakest in older patients (age > 41 years, R2 = 0.23, p = .003). Conclusions: Using both multiple linear regression and a machine-learning-based algorithm of patient data from IVF cycles, we were able to predict patients at risk for premature LH rise and/or LH surge. Utilizing this model may help prevent IVF cycle cancellation and better timing of ovulation triggering.

Comparative Analysis of Commercial Immunoassays for the Determination of Total, Intact, and Nonintact Luteinizing Hormone in Urine.

BACKGROUND: In our recent publications, we reported the identification of three different molecular forms of total luteinizing hormone (LH) in urine, the intact LH, the free beta-subunit (LHß), and its core fragment of LHß (LHßcf), the latter two establishing the nonintact portion of LH. Following the discontinuation of the Delfia immunofluorometric assay (IFMA) (Wallac, PerkinElmer Finland, Finland), a leading method for detecting urinary LH for 30 years, this study seeks to assess the efficacy of three alternative commercial immunoassays in identifying various forms of U-LH. METHODS: Diluted urine samples underwent gel filtration to separate them into fractions, each containing different forms of LH. These were then assayed using Delfia IFMA, Architect LH (Abbott, USA), Elecsys LH Cobas (Roche, Switzerland), and Immulite 2000 LH (Siemens, Germany) immunoassays. RESULTS: Both Delfia and Immulite assays detected total U-LH, that is, all three forms of U-LH, including intact LH, LHß, and LHßcf. Cobas detected only intact LH and LHß, whereas Architect detected solely the intact LH. CONCLUSIONS: Immulite assay can be an alternative tool to detect all forms of urinary LH, a feature likely to be instrumental in developing noninvasive, practical, and scalable solutions for evaluating total U-LH changes during minipuberty in neonates, during the onset of central puberty in peripubertal children, puberty-associated disorders in adolescents, and the fertility window in women, with a special focus on postpeak changes.

Evaluating breast ultrasonography as a complementary diagnostic method in girls with central precocious puberty.

BACKGROUND: Assessment of breast development by physical examination can be difficult in the early stages and in overweight girls. OBJECTIVE: To investigate ultrasonography (US) for evaluation of early breast development. MATERIALS AND METHODS: In a prospective study, 125 girls (age 7.1 ± 1.5 years) with breast development before 8 years underwent US breast staging, breast volume, and elastography, in addition to clinical/hormonal evaluation for precocious puberty. Accuracy of US for determining breast development and predicting progression to central precocious puberty was investigated. RESULTS: Physical examination revealed glandular breast enlargement in 100 and predominantly lipomastia in 25. Breast US in the former confirmed glandular breast development in 92 (group 1, physical examination and US positive), but not in 8 (group 2, physical examination positive, US negative). Comparison of the two groups demonstrated lower Tanner and US staging, bone age/chronological age, basal luteinizing hormone (LH), breast volume, and uterine volume in group 2. In the 25 lipomastia patients, US demonstrated no breast tissue in 19 (group 3, physical examination and US negative), but US stage ≥ II in 6 (group 4, physical examination negative, US positive) without differences in clinical parameters. After follow-up of 19.8 ± 4.2 months, 46/125 subjects were diagnosed with precocious puberty. US stage, total breast volume, and shear-wave speeds were significantly higher in these 46 patients. Multivariate analyses demonstrated breast volume > 3.4 cc had odds ratio of 11.0, sensitivity of 62%, and specificity of 89, in predicting progression to precocious puberty, being second only to stimulated LH for all variables. CONCLUSION: Breast US is a useful predictive tool for diagnosis of precocious puberty in girls. Higher US stages and higher breast volume on US increased the likelihood of eventual diagnosis of precocious puberty.