The beneficial effect of Allium Cepa bulb extract on reproduction of rats; A two-generation study on fecundity and sex hormones.

Allium Cepa Linn. (Onions) has extensively been used in traditional medicine, is one of the important Allium species regularly used in our daily diet, and has been the source of robust phenolic compounds. The current study is intended to evaluate the fecundity-enhancing effect of A. Cepa on the reproductive performance of two successive generations of rats; F0 and F1. A. Cepa extract was initially tested for in vitro antioxidant assay via DPPH and ROS, followed by in vivo toxicity testing. In the fecundity assessment, eighteen pairs of male and female rats (n = 36, 1:1, F0 generation) were divided into three groups and dosed with 75mg/kg and 150 mg/kg daily of A. Cepa extract and saline respectively, up to pre-cohabitation, cohabitation, gestation and lactation period. The reproductive performance, including body weight, live birth index, fertility index, and litter size, was assessed. Various parameters like Hematological, Hormonal (FSH, LH, Testosterone, estradiol), antioxidant markers (SOD, Glutathione peroxidase) and lipid profile of F0 and F1 generations were assessed with evaluation of histopathology of male and female organs. Ethanolic extract of A. Cepa showed the greatest antioxidant potential in DPPH and ROS methods. The continued exposure of the F0 and F1 generations to A. Cepa extract did not affect body weight, fertility index, litter size, and survival index. However, semen pH, sperm motility, sperm count, sperm viability, and semen volume were significantly improved in both generations. We have found pronounced fecundity outcomes in both genders of F0 and F1 generations with A. Cepa 150mg/kg/day extract as compared to control. Results showed that A. Cepa significantly increased (P < 0.05) hemoglobin, follicular stimulating hormone (FSH), luteinizing hormone (LH), plasma testosterone and glutathione peroxidase activities, while total lipid, LDL, and cholesterol were significantly decreased (P < 0.05) in both generations. Histology of both generations of animals reveals enhanced spermatogenesis and enhanced folliculogenesis with improved architecture. Altogether, the present results suggest that A. Cepa extract improved fecundity in both male and female rats by improving hormonal activities and oxidative stress.

Granulosa Cells Alone, Without Theca Cells, Can Mediate LH-induced Oocyte Meiotic Resumption.

Signaling in the granulosa cells of mammalian ovarian follicles is necessary for maintaining prophase arrest in the oocyte and for mediating the resumption of meiosis in response to luteinizing hormone (LH). However, the follicle also includes an outer layer of theca cells, some of which express receptors for LH. To investigate whether theca cells are required for maintaining meiotic arrest and reinitiating meiosis in response to LH, we mechanically separated the granulosa cells and oocyte from the theca and basal lamina. This was accomplished by cutting a slit in the outer surface of isolated follicles such that the mural granulosa cells and cumulus-oocyte complex were extruded from the theca shell, forming a lawn of cells on an organotypic membrane. The remnant of theca cells and basal lamina was then removed. The separation of the granulosa cells from the theca cells and basal lamina was demonstrated by immunofluorescence localization of endomucin (blood vessels of the theca) and laminin gamma (basal lamina). Cells comprising these granulosa cell-oocyte complexes expressed LH receptors and were connected by gap junctions. Oocytes within these granulosa cell complexes maintained meiotic arrest and resumed meiosis in response to LH, showing that the granulosa cells alone, without theca cells, transduce these signals. This semi-intact and mostly 2-dimensional preparation could facilitate imaging studies of follicle physiology.

The effects of flexible short protocol with gonadotropin-releasing hormone antagonist on preventing premature ovulation in poor responders.

PURPOSE: The proportion of patients with poor ovarian response (POR) is increasing, but effective treatment remains a challenge. To control the hidden peaks of luteinizing hormone (LH) and premature ovulation for poor responders, this study investigated the efficacy of flexible short protocol (FSP) with gonadotropin-releasing hormone antagonist (GnRH-ant) on trigger day. METHODS: The 662 cycles of POR patients were retrospectively analyzed. The cohort was divided into control and intervention groups. The intervention group (group A) with 169 cycles received a GnRH-ant given on trigger day. The control (group B) with 493 cycles received only FSP. The clinical outcomes of the two groups were compared. RESULTS: Compared with group B, with gonadotropin-releasing hormone antagonist (GnRH-ant) on trigger day in group A the incidences of spontaneous premature ovulation decreased significantly (2.37% vs. 8.72%, P < 0.05). The number of fresh embryo-transfer cycles was 45 in group A and 117 in group B. There were no significant differences in clinical outcomes, including implantation rate, clinical pregnancy rate, live birth rate and the cumulative live birth rate (12.0% vs. 9.34%; 22.22% vs. 21.93%; 17.78% vs. 14.91%; 20.51% vs. 20%, respectively; P > 0.05) between the two group. CONCLUSION: FSP with GnRH-ant addition on trigger day had no effect on clinical outcomes, but could effectively inhibit the hidden peaks of luteinizing hormone (LH) and spontaneous premature ovulation in POR. Therefore, it is an advantageous option for POR women.

Pulsatile Gonadotropin-Releasing Hormone Therapy Is Associated With Better Spermatogenic Outcomes than Gonadotropin Therapy in Patients With Pituitary Stalk Interruption Syndrome.

OBJECTIVE: To compare the effects of combined gonadotropin and pulsatile gonadotropin-releasing hormone (GnRH) therapy on spermatogenesis in patients with pituitary stalk interruption syndrome (PSIS). METHODS: Male patients with PSIS (N = 119) were retrospectively studied. Patients received pulsatile GnRH therapy (N = 59) were divided into response and poor-response groups based on luteinizing hormone (LH) levels after 1-month treatment with a cutoff value of 1 or 2 IU/L. Participants with gonadotropin therapy were divided into human menopausal gonadotropin (hMG)/human chorionic gonadotropin (hCG) group (N = 60), and patients with pulsatile GnRH therapy were classified into GnRH group (N = 28) with treatment duration ≥6 months. RESULTS: The overall success rates of spermatogenesis for hMG/hCG and GnRH therapy were 51.67% (31/60) vs 33.90% (20/59), respectively. GnRH group required a shorter period to induce spermatogenesis (8 vs 15 months, P = .019). hMG/hCG group had higher median total testosterone than GnRH group [2.16, interquartile range(IQR) 1.06-4.89 vs 1.31, IQR 0.21-2.26 ng/mL, P = .004]. GnRH therapy had a beneficial effect on spermatogenesis compared to hMG/hCG therapy (hazard ratio 1.97, 95% confidence interval 1.08-3.57, P = .026). In patients with pulsatile GnRH therapy, compared with the poor-response group, the response group had a higher successful spermatogenesis rate (5.00% vs 48.72%, P = .002) and higher median basal total testosterone (0.00, IQR 0.00-0.03 vs 0.04, IQR 0.00-0.16 ng/mL, P = .026) with LH = 1 IU/L as the cutoff value after 1-month pulsatile GnRH therapy. CONCLUSIONS: Pulsatile GnRH therapy was superior to hMG/hCG therapy for spermatogenesis in patients with PSIS. Earlier spermatogenesis and higher concentrations of sperm could be obtained in the GnRH group if patients received therapy over 6 months.

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.

A novel lncRNA LOC105613571 binding with BDNF in pituitary promotes gonadotropin secretion by AKT/ERK-mTOR pathway in sheep associated with prolificacy.

The pituitary is a vital endocrine organ for synthesis and secretion of gonadotropic hormones (FSH and LH), and the gonadotropin showed fluctuations in animals with different fecundity. Long non-coding RNAs (lncRNAs) have been identified as regulatory factors for the reproductive process. However, the profiles of lncRNAs and their roles involved in sheep fecundity remains unclear. In this study, we performed RNA-sequencing for the sheep pituitary gland associated with different fecundity, and identified a novel candidate lncRNA LOC105613571 targeting BDNF related to gonadotropin secretion. Our results showed that expression of lncRNA LOC105613571 and BDNF could be significantly upregulated by GnRH stimulation in sheep pituitary cells in vitro. Notably, either lncRNA LOC105613571 or BDNF silencing inhibited cell proliferation while promoted cell apoptosis. Moreover, lncRNA LOC105613571 knockdown could also downregulate gonadotropin secretion via inactivation AKT, ERK and mTOR pathway. In addition, co-treatment with GnRH stimulation and lncRNA LOC105613571 or BDNF knockdown showed the opposite effect on sheep pituitary cells in vitro. In summary, BDNF-binding lncRNA LOC105613571 in sheep regulates pituitary cell proliferation and gonadotropin secretion via the AKT/ERK-mTOR pathway, providing new ideas for the molecular mechanisms of pituitary functions.

Nutrition and Sexual Development in Bulls.

This manuscript provides an overview of the effects of nutrition during different stages of bull sexual development. Nutrition during the prepubertal period can modulate the hypothalamic GnRH pulse generator. Increased nutrition results in greater LH secretion, earlier puberty, and greater testicular mass in yearling bulls, whereas low nutrition has opposite effects. Targeting average daily gain from birth to 24 weeks of age to > 1.2 kg/d and limiting gain after 24 weeks of age to < 1.6 kg/d is recommended to optimize bull sexual development.

Phoenixin-14 as a novel direct regulator of porcine luteal cell functions†.

Phoenixin is a neuropeptide with a well-established role in the central regulation of reproductive processes; however, knowledge regarding its role in the ovary is limited. One of the main active phoenixin isoforms is phoenixin-14, which acts through G protein-coupled receptor 173. Our research hypothesis was that phoenixin-14 is expressed in porcine corpus luteum and exerts luteotropic action by affecting the endocrine function of luteal cells through G protein-coupled receptor 173 and protein kinase signaling. Luteal cells were cultured to investigate the effect of phoenixin-14 (1-1000 nM) on endocrine function. We showed that phoenixin-14 and G protein-coupled receptor 173 are produced locally in porcine corpus luteum and their levels change during the estrous cycle. We detected phoenixin-14 immunostaining in the cytoplasm and G protein-coupled receptor 173 in the cell membrane. Plasma phoenixin levels were highest during the early luteal phase. Interestingly, insulin, luteinizing hormone, progesterone, and prostaglandins decreased phoenixin-14 levels in luteal cells. Phoenixin-14 increased progesterone, estradiol, and prostaglandin E2 secretion, but decreased prostaglandin F2α, upregulated the expression of steroidogenic enzymes, and downregulated receptors for luteinizing hormone and prostaglandin. Also, phoenixin-14 increased the expression of G protein-coupled receptor 173 and the phosphorylation of extracellular signal-regulated kinase 1/2, protein kinase B, inhibited the phosphorylation of protein kinase A, and had mixed effect on AMP-activated protein kinase alpha and protein kinase C. G protein-coupled receptor 173 and extracellular signal-regulated kinase 1/2 mediated the effect of phoenixin-14 on endocrine function of luteal cells. Our results suggest that phoenixin is produced by porcine luteal cells and can be a new regulator of their function.

Effect of follicle-stimulating hormone and luteinizing hormone on apoptosis, autophagy, and the release and reception of some steroid hormones in yak granulosa cells through miR-23a/ASK1 axis.

Follicle-stimulating hormone (FSH), luteinizing hormone (LH), miR-23a, apoptosis signal-regulating kinase 1(ASK1)/c-Jun N-terminal kinase (JNK), autophagy and apoptosis play crucial roles in follicular development. However, their role in yak granulosa cells (GCs) remains unknown. Therefore, we examined the effect of miR-23a, ASK1, FSH, and LH on apoptosis, autophagy, and the release and reception of some steroid hormones in these cells. Our results showed that miR-23a overexpression significantly increased the abundance of Beclin1, the LC3II/I ratio, and the number of Ad-mRFP-GFP-LC3-labeled autophagosomes, and decreased p62 abundance. Additionally, Bax abundance and the number of terminal deoxynucleotidyl transferase deoxynucleotide triphosphate nick end labeling-positive cells were reduced, while Bcl2 expression was increased. Overexpression of miR-23a also significantly increased the abundance of estradiol receptor α (ER-α) and ß (ER-ß) and the concentrations of estradiol (E2), progesterone (P4) in yak GCs. Here, treating yak GCs with miR-23a decreased ASK1 expression, which regulates ASK1/JNK-mediated apoptosis, autophagy, E2 and P4 levels, and ER-α/ß abundance. In contrast, treatment of yak GCs with FSH (10 µg/mL) and LH (100 µg/mL) increased miR-23a abundance, regulating the subsequent effect on ASK1/JNK-mediated apoptosis, autophagy, ER-α/ß abundance, and E2 and P4 concentrations. In conclusion, miR-23a enhances autophagy in yak GCs, attenuates apoptosis, and increases ER-α/ß abundance and E2 and P4 concentrations by downregulating ASK1. Additionally, FSH and LH can regulate these effects of miR-23a by altering its expression. These results provide important insights that can inform the development of strategies to reduce abnormal follicular atresia and improve the reproductive rate of yaks.

Conditional Oprk1-dependent Kiss1 deletion in kisspeptin neurons caused estrogen-dependent LH pulse disruption and LH surge attenuation in female rats.

The gonadotropin-releasing hormone (GnRH) pulse and surge are considered to be generated by arcuate kisspeptin/neurokinin B/dynorphin A (KNDy) neurons and anteroventral periventricular nucleus (AVPV) kisspeptin neurons, respectively, in female rodents. The majority of KNDy and AVPV kisspeptin neurons express κ-opioid receptors (KORs, encoded by Oprk1) in female rodents. Thus, this study aimed to investigate the effect of a conditional Oprk1-dependent Kiss1 deletion in kisspeptin neurons on the luteinizing hormone (LH) pulse/surge and fertility using Kiss1-floxed/Oprk1-Cre rats, in which Kiss1 was deleted in cells expressing or once expressed the Oprk1/Cre. The Kiss1-floxed/Oprk1-Cre female rats, with Kiss1 deleted in a majority of KNDy neurons, showed normal puberty while having a one-day longer estrous cycle and fewer pups than Kiss1-floxed controls. Notably, ovariectomized (OVX) Kiss1-floxed/Oprk1-Cre rats showed profound disruption of LH pulses in the presence of a diestrous level of estrogen but showed apparent LH pulses without estrogen treatment. Furthermore, Kiss1-floxed/Oprk1-Cre rats, with Kiss1 deleted in approximately half of AVPV kisspeptin neurons, showed a lower peak of the estrogen-induced LH surge than controls. These results suggest that arcuate and AVPV kisspeptin neurons expressing or having expressed Oprk1 have a role in maintaining normal GnRH pulse and surge generation, the normal length of the estrous cycle, and the normal offspring number in female rats.

Effect of dexamethasone administration on gonadal-fertility functions in female albino rats.

Introduction: dexamethasone is misused for skin whitening with broad effects on steroidogenesis and ovarian functions. Here in we investigated the impact of dexamethasone administration on gonadotropin Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH), prolactin, and ovarian tissues in albino rats. Methods: in the experimental study, 36 female albino rats weighting (140-162 g) were divided into three groups: control, normal dose received dexamethasone (8.3 µg/kg/day) and high dose (24.9 µg/kg/day), for 30 and 60 days. follicle stimulating hormone, luteinizing hormone, and prolactin (PRL) were measured. Histological ovarian sections were examined. Results: luteinizing hormone, follicle stimulating hormone and prolactin significantly increased (p-value < 0.05) following dexamethasone treatment compared to control. The ovary sections showed degenerative tissue with necrosis of the Graafian follicles, stromal fibrosis, and vacuolation of the interstitial cells. Conclusion: the study concludes that dexamethasone administration has a potentially adverse effect on gonadotropin, prolactin, and ovarian follicle cells in female albino rats.

Luman regulates the activity of the LHCGR promoter.

Testosterone in male mammals is mainly secreted by testicular Leydig cells, and its secretion process is regulated by the hypothalamic-pituitary-gonadal axis. After receiving the luteinizing hormone (LH) stimulus signal, the lutropin/choriogonadotropin receptor (LHCGR) on the Leydig cell membrane transfers the signal into the cell and finally increases the secretion of testosterone by upregulating the expression of steroid hormone synthase. In previous experiments, we found that interfering with the expression of the Luman protein can significantly increase testosterone secretion in MLTC-1 cells. In this experiment, we found that knockdown of Luman in MLTC-1 cells significantly increased the concentration of cAMP and upregulated the expression of AC and LHCGR. Moreover, an analysis of the activity of the LHCGR promoter by a dual luciferase reporter system showed that knockdown of Luman increased the activity of the LHCGR promoter. Therefore, we believe that knockdown of Luman increased the activity of the LHCGR promoter and upregulated the expression of LHCGR, thereby increasing the concentration of intracellular cAMP and ultimately leading to an increase of testosterone secretion by MLTC-1 cells.

Hormone measurements and histomorphological observations in male Bactrian camels.

The aim of this study was to investigate the effect of age on the hypothalamic-pituitary-gonadal (HPG) axis hormones and to determine the morphological changes of the testis. The Bactrian camels were divided into two groups based on their ages. The results showed that the testicular weight was significantly heavier in adult male camels than in pubertal male camels (P < 0.05). There were also significant differences between testicular length, testicular width, and testicular volume (P < 0.05). In the testes of both pubertal and adult male camels, Sertoli cells, spermatogonia, spermatocytes, round spermatids, and elongated spermatids were observed. Adult male camels had more Sertoli cells (P < 0.01) and elongated spermatids (P < 0.05). The concentrations of testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were higher in the plasma and testes of adult camels than in pubertal camels (P < 0.05). E2 concentrations were lower in adult camels than in pubertal camels (P < 0.05). The testosterone levels in testicular tissue were higher than in blood plasma in both adult and pubertal stage (P < 0.05). In conclusion, these findings provide supportive knowledge and show the significant differences in terms of testicular volume, testicular hormone concentrations, and testicular morphology between different developmental stages in Bactrian camels.

The involvement of let-7 in hCG-induced progesterone synthesis via regulating p27Kip1 and p21Cip1 expression.

Progesterone is essential in females to maintain a regular menstrual cycle and pregnancy. The luteinizing hormone (LH) surge induces the luteinization of granulosa cells and thecal cells to form the corpus luteum, which is responsible for progesterone synthesis. However, the specific mechanism of how hCG, the analog of LH, regulates progesterone synthesis has yet to be fully discovered. In this study, we found that progesterone level was increased in adult wild-type pregnant mice 2 and 7 days post-coitum, along with a decrease in let-7 expression compared with the estrus stage. Besides, the let-7 expression was negatively correlated with progesterone level in post-delivery day 23 wild-type female mice after being injected with PMSG and hCG. Then, using let-7 transgenic mice and a human granulosa cell line, we found that overexpression of let-7 antagonized progesterone level via targeting p27Kip1 and p21Cip1 and steroidogenic acute regulatory protein (StAR) expression, which is a rate-limiting enzyme in progesterone synthesis. Furthermore, hCG suppressed let-7 expression by stimulating the MAPK pathway. This study elucidated the role of microRNA let-7 in regulating hCG-induced progesterone production and provided new insights into its role in clinical application.

Sphingosine-1-phosphate regulation of luteinising hormone-induced steroidogenesis and proliferation of bovine theca cells in vitro.

CONTEXT: Sphingosine-1-phosphate (S1P) is synthesised by follicle granulosa cells under the influence of follicle-stimulating hormone and seems to be necessary for the biological effects of this gonadotrophin. AIMS: To determine if luteinising hormone (LH) increases S1P production and if this sphingolipid, either induced by LH or added to culture media, regulates steroidogenesis and cell viability in bovine theca cells. METHODS: We used bovine theca cell cultures treated with: S1P (0, 0.1, 1 and 10µM; Experiment 1), LH (0, 0.02, 0.2 and 2ngmL-1 ; Experiment 2) and LH (0.02ngmL-1 ) plus a sphingosine kinase inhibitor (SKI-178; 0, 5 and 10µM; Experiment 3). KEY RESULTS: Treatment with S1P did not affect (P >0.05) theca cell viability or their ability to produce progesterone and testosterone. LH (0.02ngmL-1 ) increased (P <0.05) S1P production, and stimulated the expression of phosphorylated sphingosine kinase-1 (pSPHK1). However, the inhibition of SPHK1, by a specific SPHK1 inhibitor (SKI-178), reduced (P <0.05) cell viability and progesterone secretion. Additionally, the use of SKI-178 increased theca cell testosterone production (P<0.05). CONCLUSIONS: S1P added to culture media did not affect cell viability or steroid synthesis. However, LH stimulated the production of S1P, by increasing phosphorylation of SPHK1 in theca cells. This intracellular S1P was inhibitory on testosterone production but augmented progesterone and viable cell number. IMPLICATIONS: These results suggest a novel signalling pathway for LH in theca cells and underline the importance of S1P in the regulation of steroid synthesis.

Intrafollicular Retinoic Acid Signaling Is Important for Luteinizing Hormone-Induced Oocyte Meiotic Resumption.

It has been clear that retinoic acid (RA), the most active vitamin A (VA) derivative, plays a central role in governing oocyte meiosis initiation. However, it has not been functionally determined if RA participates in luteinizing hormone (LH)-induced resumption from long-lasting oocyte meiotic arrest, which is essential for haploid oocyte formation. In the present study, using well-established in vivo and in vitro models, we identified that intrafollicular RA signaling is important for normal oocyte meiotic resumption. A mechanistic study indicated that mural granulosa cells (MGCs) are the indispensable follicular compartment for RA-prompted meiotic resumption. Moreover, retinoic acid receptor (RAR) is essential for mediating RA signaling to regulate meiotic resumption. Furthermore, we found zinc finger protein 36 (ZFP36) is the transcriptional target of RAR. Both RA signaling and epidermal growth factor (EGF) signaling were activated in MGCs in response to LH surge, and two intrafollicular signalings cooperate to induce rapid Zfp36 upregulation and Nppc mRNA decrease, which is critical to LH-induced meiotic resumption. These findings extend our understanding of the role of RA in oocyte meiosis: RA not only governs meiotic initiation but also regulates LH-induced meiotic resumption. We also emphasize the importance of LH-induced metabolic changes in MGCs in this process.

Ovulatory signal-triggered chromatin remodeling in ovarian granulosa cells by HDAC2 phosphorylation activation-mediated histone deacetylation.

BACKGROUND: Epigenetic reprogramming is involved in luteinizing hormone (LH)-induced ovulation; however, the underlying mechanisms are largely unknown. RESULTS: We here observed a rapid histone deacetylation process between two waves of active transcription mediated by the follicle-stimulating hormone (FSH) and the LH congener human chorionic gonadotropin (hCG), respectively. Analysis of the genome-wide H3K27Ac distribution in hCG-treated granulosa cells revealed that a rapid wave of genome-wide histone deacetylation remodels the chromatin, followed by the establishment of specific histone acetylation for ovulation. HDAC2 phosphorylation activation coincides with histone deacetylation in mouse preovulatory follicles. When HDAC2 was silenced or inhibited, histone acetylation was retained, leading to reduced gene transcription, retarded cumulus expansion, and ovulation defect. HDAC2 phosphorylation was associated with CK2α nuclear translocation, and inhibition of CK2α attenuated HDAC2 phosphorylation, retarded H3K27 deacetylation, and inactivated the ERK1/2 signaling cascade. CONCLUSIONS: This study demonstrates that the ovulatory signal erases histone acetylation through activation of CK2α-mediated HDAC2 phosphorylation in granulosa cells, which is an essential prerequisite for subsequent successful ovulation.

Effect of a neurokinin 3 receptor-selective agonist administration on the embryos recovered from superovulated cows.

Superovulation (SOV) treatment of cows results in unovulated follicles and inconsistent quality of the recovered embryos. It has been demonstrated that luteinizing hormone (LH) secretion is suppressed during SOV treatment of cows, which may cause insufficient follicle development and variation in the development of recovered embryos and unovulated follicles. Pulsatile gonadotropin-releasing hormone/LH secretion is controlled by the activity of kisspeptin, neurokinin B and dynorphin (KNDy) neurons in the arcuate nucleus in many mammals. As neurokinin B promotes the activity of KNDy neurons, we hypothesized that senktide, a neurokinin B receptor agonist, has the potential as a therapeutic drug to improve the ovulation rate and quality of recovered embryos in SOV-treated cows via stimulation of LH secretion. Senktide was administered intravenously (30 or 300 nmol/min) for 2 h, beginning from 72 h after the start of SOV treatment. LH secretion was examined before and after administration, and embryos were collected 7 d after estrus. Senktide administration increased LH secretion in SOV-treated cows. The ratios of code 1, code 1 and 2, and blastocyst stage embryos to recovered embryos were increased by senktide (300 nmol/min) administration. Moreover, the mRNA levels of MTCO1, COX7C, and MTATP6 were upregulated in recovered embryos of senktide (300 nmol/min)-administered animals. These results indicate that the administration of senktide to SOV-treated cows enhances LH secretion and upregulates the expression of genes involved in mitochondrial metabolism in embryos, thereby improving embryo development and embryo quality.

The State of the Organs of the Female Reproductive System after a 5-Day "Dry" Immersion.

The impact of weightlessness on the female reproductive system remains poorly understood, although deep space exploration is impossible without the development of effective measures to protect women's health. The purpose of this work was to study the effect of a 5-day "dry" immersion on the state of the reproductive system of female subjects. On the fourth day of the menstrual cycle after immersion, we observed an increase in inhibin B of 35% (p < 0.05) and a decrease in luteinizing hormone of 12% (p < 0.05) and progesterone of 52% (p < 0.05) compared with the same day before immersion. The size of the uterus and the thickness of the endometrium did not change. On the ninth day of the menstrual cycle after immersion, the average diameters of the antral follicles and the dominant follicle were, respectively, 14% and 22% (p < 0.05) higher than before. The duration of the menstrual cycle did not change. The obtained results may indicate that the stay in the 5-day "dry" immersion, on the one hand, can stimulate the growth of the dominant follicle, but, on the other hand, can cause functional insufficiency of the corpus lutea.

Enkephalin-δ Opioid Receptor Signaling Mediates Glucoprivic Suppression of LH Pulse and Gluconeogenesis in Female Rats.

Energy availability is an important regulator of reproductive function at various reproductive phases in mammals. Glucoprivation induced by 2-deoxy-D-glucose (2DG), an inhibitor of glucose utilization, as an experimental model of malnutrition suppresses the pulsatile release of GnRH/LH and induces gluconeogenesis. The present study was performed with the aim of examining whether enkephalin-δ-opioid receptor (DOR) signaling mediates the suppression of pulsatile GnRH/LH release and gluconeogenesis during malnutrition. The administration of naltrindole hydrochloride (NTI), a selective DOR antagonist, into the third ventricle blocked the suppression of LH pulses and part of gluconeogenesis induced by IV 2DG administration in ovariectomized rats treated with a negative feedback level of estradiol-17â€…ß (OVX + low E2). The IV 2DG administration significantly increased the number of Penk (enkephalin gene)-positive cells coexpressing fos (neuronal activation marker gene) in the paraventricular nucleus (PVN), but not in the arcuate nucleus (ARC) in OVX + low E2 rats. Furthermore, double in situ hybridization for Penk/Pdyn (dynorphin gene) in the PVN revealed that approximately 35% of the PVN Penk-expressing cells coexpressed Pdyn. Double in situ hybridization for Penk/Crh (corticotropin-releasing hormone gene) in the PVN and Penk/Kiss1 (kisspeptin gene) in the ARC revealed that few Penk-expressing cells coexpressed Crh and Kiss1. Taken together, these results suggest that central enkephalin-DOR signaling mediates the suppression of pulsatile LH release during malnutrition. Moreover, the current study suggests that central enkephalin-DOR signaling is also involved in gluconeogenesis during malnutrition in female rats.