Regulation Of Estradiol Research Articles

Chronic Administration of Cannabinoid Agonists ACEA, AM1241, and CP55,940 Induce Sex-Specific Differences in Tolerance and Sex Hormone Changes in a Chemotherapy-Induced Peripheral Neuropathy.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of chemotherapy treatment, routinely manifesting as increased pain sensitivity (allodynia) in distal extremities. Despite its prevalence, effective treatment options are limited. Cannabinoids are increasingly being evaluated for their ability to treat chronic pain conditions, including CIPN. While previous studies have revealed sex differences in cannabinoid-mediated antinociception in acute and chronic pain models, there is a paucity of studies addressing potential sex differences in the response of CIPN to cannabinoid treatment. Therefore, we evaluated the long-term antiallodynic efficacy of cannabinoid receptor type 1 (CB1)-selective, cannabinoid receptor type 2 (CB2)-selective, and CB1/CB2 mixed agonists in the cisplatin CIPN model, using both male and female mice. CB1 selective agonism was observed to have sex differences in the development of tolerance to antiallodynic effects, with females developing tolerance more rapidly than males, while the antiallodynic effects of selective CB2 agonism lacked tolerance development. Compound-specific changes to the female estrous cycle and female plasma estradiol levels were noted, with CB1 selective agonism decreasing plasma estradiol while CB2 selective agonism increased plasma estradiol. Chronic administration of a mixed CB1/CB2 agonist resulted in increased mRNA expression of proinflammatory cytokines and endocannabinoid regulatory enzymes in female spinal cord tissue. Ovarian tissue was noted to have proinflammatory cytokine mRNA expression following administration of a CB2 acting compound while selective CB1 agonism resulted in decreased proinflammatory cytokines and endocannabinoid regulatory enzymes in testes. These results support the need for further investigation into the role of sex and sex hormones signaling in pain and cannabinoid-mediated antinociceptive effects. SIGNIFICANCE STATEMENT: CIPN is a common side effect of chemotherapy. We have found that both CB1 and CB2 receptor agonism produce antinociceptive effects in a cisplatin CIPN model. We observed that tolerance to CB1-mediated antinociception developed faster in females and did not develop for CB2-mediated antinociception. Additionally, we found contrasting roles for CB1/CB2 receptors in the regulation of plasma estradiol in females, with CB1 agonism attenuating estradiol and CB2 agonism enhancing estradiol. These findings support the exploration of cannabinoid agonists for CIPN.

Immune-hormonal imbalance in chemical cancerogenesis

The present article deals with experimental and clinical aspects of immuno-hormonal interactions in chemical carcinogenesis i.e., formation of DNA-adducts with chemical carcinogens as a trigger of tumor initiation; synthesis of specific antibodies as markers of human exposure to environmental carcinogens; immunomodulation of chemical carcinogenesis by the specific antibodies in experimental studies; interactions of antibodies against environmental carcinogens with endogenous steroid hormones in human carcinogenesis; immunological interference and inversion of immuno-hormonal interactions by the action of antibodies against environmental carcinogens; immune stimulation of tumor progression in cancer patients. It is shown that antibodies specific to estradiol and progesterone participate in regulation of serum estradiol and progesterone levels in healthy women. Excessive production of antibodies against benzo[a]pyrene is associated with impaired physiological balance between the levels of antibodies to estradiol and progesterone, thus causing disturbed physiological balance between serum estradiol and progesterone. Immuno-hormonal imbalance promotes tumor initiation, its growth and progression. The new approaches to the personalized cancer immunoprediction and immune prevention are discussed. Coordinated synthesis of antibodies against benzo[a]pyrene and estradiol seems to reflect production of DNA-adducts with genotoxic metabolic effects of these compounds manifesting as synergistic carcinogenic effects upon the target cells. Hence, simultaneously increased levels of serum antibodies against benzo[a]pyrene and estradiol in healthy people may be considered an immunological marker of high oncological risk and an reason to use of new immunoprotective tools against polycyclic aromatic hydrocarbons and phytoestrogens. However, ability of these antibodies to raise the blood serum levels of environmental carcinogens and endogenous estradiol, as shown in vitro and in vivo, excludes the opportunity for active cancer immune prevention. Usage of anticarcinogen vaccines aimed for induction of protective secretory antibodies is likely to further increase high levels of procarcinogenic serum antibodies against benzo[a]pyrene and estradiol, followed by additional enhancement of immuno-hormonal imbalance and promotion of carcinogenesis. Development of probiotics transduced with genes encoding human antibodies against environmental carcinogens may present an alternative approach to cancer immune prevention. The antibodies produced by such probiotics would bind appropriate carcinogens and prevent their invasion into the organism, thus inhibiting emergence of DNA-adducts and suppressing synthesis of specific autoantibodies that may promote carcinogenesis. The aim is to substantiate the concept of immuno-hormonal imbalance for the carcinogen-induced hormone-dependent tumors.

FSH stimulated bovine granulosa cell steroidogenesis involves both canonical and noncanonical WNT signaling

Gonadotrophins play key roles in follicular development; however, the underlying molecular mechanisms are not fully understood. Follicle stimulating hormone (FSH) regulation of aromatase and subsequent estradiol (E2) production relies on β-catenin, a key effector of WNT signaling. We previously demonstrated that treatment with the canonical WNT inhibitor, IWR-1, reduced FSH induced bovine granulosa cell E2 production in vitro. Here we demonstrated that intrafollicular injection in vivo with IWR-1 alters steroidogenesis and triggers a significant decrease in estrogen to progesterone ratio in the IWR-1 treated follicles compared to diluent injected control follicles. We next examined markers of canonical and noncanonical WNT signaling in dominant and subordinate follicles collected at different stages of follicular development and showed that protein for both CTNNB1 (canonical pathway) and phosphorylated (p)-LEF1 (noncanonical pathway) was significantly elevated in dominant compared to subordinate follicles at the early dominance stage of development. Therefore, we hypothesized that canonical and/or noncanonical WNT ligands modulate FSH stimulated E2 production. Hence, we examined the effects of specific WNT ligands on FSH stimulated E2 production in the absence of endogenous WNT production in vitro. Universal WNT signaling inhibitor, LGK-974 was able to inhibit FSH stimulation of E2 and reduce the abundance of proteins linked to canonical and noncanonical WNT pathway activation. Supplementation with the canonical ligand WNT2b did not affect the inhibitory effects of LGK-974 on FSH stimulated E2 production but rescued the LGK-974 mediated inhibition of CTNNB1 (canonical pathway) but not p-LEF1, p-JNK or p-P38 abundance (noncanonical pathway) abundance. In contrast, WNT5a treatment rescued FSH stimulated estradiol production and indices of activation of both the canonical (CTNNB1) and noncanonical (p-LEF1, p-JNK and p-P38) WNT signaling pathways in LGK-974 treated granulosa cells. Taken together, these results suggest that both canonical and noncanonical WNT pathways activation is linked to FSH stimulation of E2 production by bovine granulosa cells.

Anti-perimenopausal osteoporosis effects of Erzhi formula via regulation of bone resorption through osteoclast differentiation: A network pharmacology-integrated experimental study

Ethnopharmacological relevanceErzhi formula (EZF) consists of Ecliptae herba (EH) and Fructus Ligustri Lucidi (FLL) at a ratio 1:1, and constitutes a well-known formula in China that is commonly used for treating menopausal diseases. Aim of the studyIn this study, we explored the pharmacologic actions and potential molecular mechanisms underlying EZF's action in preventing and treating osteoporosis. Materials and methodsThe active components and related targets of EZF's anti-osteoporotic effects were predicted by network pharmacology, and functional enrichment analysis was also performed. We then used an osteoporosis model of ovariectomized (OVX) mice to detect the effects of EZF on osteoporosis. ResultsThe results from network pharmacology identified a total of 10 active ingredients from EH and 13 active ingredients from FLL that might affect 65 potential therapeutic targets. GO enrichment analysis revealed that EZF affected bone tissue primarily via hormone (particularly estradiol)-related pathways and bone resorption by osteoclast differentiation. KEGG analysis demonstrated that bone-related factors such as Runt-related transcription factor 2 (Runx2), Ca2, estrogen receptor1 (ESR1), androgen receptors (AR), and TNFα served as the primary targets during osteoclastic differentiation. In vivo experiments showed that the formula significantly improved the diminution in estrogen and the subsequent uterine atrophy induced by ovariectomy (P < 0.01 or 0.05), implying that the EZF exerted its actions via regulation of estradiol and the nourishing effects of the uterus in OVX mice. Dual-energy X-ray absorptiometry and micro-CT showed that EZF significantly inhibited bone loss and improved bone micro-architecture by statistically increasing the number of bone trabeculae and decreasing the separation of bone trabeculae in OVX mice (P < 0.01 or 0.05); EZF also inhibited bone loss and enhanced bone-fracture load. Furthermore, we confirmed that EZF reduced the calcium concentrations, augmented protein and mRNA levels for Runx2 in the bone marrow, and reduced PPARγ levels. RANKL—a key downstream regulatory protein of many targets that was referred to in our results of network pharmacology as being involved in the regulation of osteoclastogenesis—was significantly diminished by EZF; it also elevated OPG content. In addition, we used monocytes of bone-marrow origin to detect the effects of the potential components of EZF on osteoclast differentiation and found that wedelolactone, oleanolic acid, echinocystic acid, luteolin, and luteolin-7-o-glucoside significantly inhibited osteoclast differentiation from monocytes induced by 25 ng/mL MCSF and 50 ng/mL RANKL (P < 0.01 or 0.05). ConclusionsOur present study indicated that EZF significantly inhibited the bone loss induced by OVX in mice by its regulation of estradiol combined with the nourishing effect of the uterus, and that it also attenuated bone resorption by decreasing the RANKL/OPG ratio so as to inhibit osteoclast maturation.

Взаимосвязи между форменными элементами крови, половыми гормонами и системой ПОЛ у женщин с эссенциальной гипертонией

У женщин, больных гипертонической болезнью, существуют тесные корреляционные взаимосвязи между различными форменными элементами крови и уровнем артериального давления, показателями деятельности сердца, тестами, характеризующими состояние гемодинамики, тромбодинамики и коагуляционной активности крови. Цель исследования - изучение роли различных форменных элементов крови и их соотношения в регуляции уровня эстрогена, прогестерона и пролактина, ТБК-активных продуктов и антиоксидантной активности у больных гипертонической болезнью. Методика. Исследования проведены на 72 больных гипертонической болезнью, контрольную группу составили 12 женщин с нормальным артериальным давлением. Больные были разделены на 2 группы: в 1-ю группу вошли 37 пациенток с гипертонической болезнью II стадии, находящиеся на гипотензивной терапии, 2-ю - составили 35 женщин с гипертонией II стадии, которые кроме медикаментозного лечения, регулярно проходили курсы кинезотерапии на протяжении 2-3 лет. Результаты. Методом корреляционного анализа установлено, что у здоровых женщин и больных гипертонической болезнью, изучаемые взаимосвязи могут носить как однонаправленный, так и разнонаправленный характер. У здоровых женщин обнаруживается прямая связь между количеством лимфоцитов и уровнем прогестерона и обратная - с уровнем пролактина. Прямая связь также выявлена между индексом нейтрофилы/базофилы и прогестероном. При гипертонии у больных 1-й группы обнаруживается прямая связь между количеством эритроцитов и прогестероном, числом эозинофилов и пролактином; индекса лимфоциты/эозинофилы с эстрадиолом; индексов нейтрофилы/моноциты, нейтрофилы/базофилы и лимфоциты/базофилы с прогестероном. Отрицательная корреляция выявляется между индексами нейтрофилы/лимфоциты и нейтрофилы/эозинофилы с пролактином. У больных 2-й группы обнаружены прямые корреляционные связи между абсолютным количеством лейкоцитов, нейтрофилов и эозинофилов и отрицательная связь индекса эритроциты/лейкоциты с пролактином. При оценке корреляционных взаимосвязей показателей крови с показателями активности оксидантно/антиоксидантной системы показано, что у здоровых женщин существуют положительные связи между числом моноцитов с содержанием ТБК-продуктов и активностью антиоксидантной системы; эозинофилов с активностью антиоксидантной системы; индекса лейкоциты/тромбоциты с уровнем ТБК-продуктов. При гипертонической болезни в группе без кинезотерапии (1-я группа) выявлена отрицательная взаимосвязь между общим числом эритроцитов и показателями активности антиоксидантной системы. Заключение. Практически все форменные элементы крови и различные их взаимоотношения у здоровых и больных гипертонической болезнью играют существенную роль в регуляции уровня эстрадиола, прогестерона, пролактина и состояния системы перекисного окисления липидов - антиоксидантная активность. Close correlations exist between different blood cells (BC), blood pressure, heart function, results of hemodynamics tests, thrombodynamics, and blood coagulation in women with hypertension. Aim. The study addressed the role of different BCs and their combinations in regulation of estrogen, progesterone, prolactin, TBA-reactive substances (TBARS), and antioxidant activity (AOA) in hypertensive patients. Methods. The study included 12 healthy women (control) and 72 patients with essential hypertension (EH). Patients with EH were divided into two groups; the first group (EH-1) consisted of 37 women with stage II EH receiving an antihypertensive therapy and the second group (EH-2) consisted of 35 women who, in addition to the drug therapy, yearly underwent 3-4 courses of kinesitherapy for 2-3 year on a regular basis. Results. Both in healthy women and patients of the EH-1 and EH-2 groups, the studied relationships were either positive or negative. In healthy women, LYM positively correlated with progesterone and inversely correlated with prolactin, and the NEU/BAS ratio positively correlated with progesterone. In patients of the EH-1 group, there were positive correlations of RBC with progesterone; EOS with prolactin; and LYM/EOS with estradiol; and NEU/MON, NEU/BAS, and LYM/BAS with progesterone. The NEU/LYM and NEU/EOS ratios inversely correlated with prolactin. In patients of the EH-2 group, there were positive correlations of WBC, NEU, and EOS with prolactin and inverse correlations of the RBC/WBC ratio with prolactin. Evaluation of correlations between blood indexes and the oxidant/antioxidant system showed that in healthy women, there were positive correlations of the MON count with TBARS and AOA; EOS with AOA; and the WBC/PLT ratio with TBARS. Patients of the EH-1 group showed a negative correlation of the total RBC count with AOA. Conclusion. In both healthy subjects and EH groups, almost all BCs and their relationships play a significant role in regulation of estradiol, progesterone, prolactin, and the lipid peroxidation/AOA system.

Activation of PPARG inhibits dominant follicle development in cattle

The peroxisome proliferator-activated receptor gamma (PPARG, also called NR1C3) is a nuclear receptor of the peroxisome proliferator-activated receptor family (PPAR). PPARs are involved in the regulation of apoptosis, cell cycle, estradiol and progesterone synthesis, and metabolism. However, the role of PPARs and their regulation during follicular development and ovulation in monovular species remain poorly understood. In this study, a well-established intrafollicular injection model was used to investigate if the PPARG participates in the regulation of dominant follicle development and ovulation in cattle. Findings from this study revealed that the relative mRNA abundance of PPARG was similar between dominant and subordinate follicles around follicle deviation, decreased after the LH surge, and increased before ovulation. In addition, a quadratic correlation was found between PPARG mRNA levels in granulosa cells and progesterone concentration in the follicular fluid. Intrafollicular injection of 50 μM Troglitazone (TGZ; a PPARG agonist) inhibited follicular growth and decreased CYP19A1 mRNA abundance in granulosa cells. These findings indicate that PPARG is involved in the regulation of steroidogenesis, follicle growth and ovulation in cattle.

41 Regulation of preovulatory estradiol and its impacts throughout the bovine estrous cycle.

41 Regulation of preovulatory estradiol and its impacts throughout the bovine estrous cycle.

The regulation of estradiol on growth dynamics of human LECs affected by increasing telomerase activity

Background Human LECs can express telomerase activity, which participates in the formation of cataract.It is reported that estrogen can increase the expression of telomerase activity in human endometrial cancer and breast cancer cells and play an important role in promoting proliferation and anti-apoptosis, but whether estrogen exerts its role on human LECs is still unclear. Objective This study aimed to investigate whether β-estradiol (β-E2) can increase the telomerase activity of human LECs and the influence of β-E2 on proliferation and apoptosis of human LECs. Method Human LECs line was cultured and passaged in vitro, and 1×10-6 mol/L β-E2 was added in the medium for 0, 6, 12, 24 and 48 hours, and reverse transcription PCR was used to determine the optimal time of the expression of human telomerase reverse transcriptase (hTERT) mRNA in the cells.Cultured cells were divided into five groups.The cells in the blank contol group were cultured in the routin medium.Ethanol of 0.1% was added in the solvent control group, and 1×10-8, 1×10-7 or 1×10-6 mol/L β-E2 was added in the medium in different contents of β-E2 groups, respectively.The relative expression level of hTERT mRNA in different groups was detected by reverse transcription PCR.Telomere repeat amplification protocol (TRAP)-ELISA was employed to determine the telomerase activity.The proliferative value of the cells was assayed by cell counting kit-8, and the apoptosis rate of the cells was examined by Hoechst33258 staining. Results The optimal time of β-E2 to rise the expression of hTERT mRNA (absorbance) was at 24 hours under the 1×10-6 mol/L.The relative expression levels of hTERT mRNA in the cells were 0.477±0.015, 0.712±0.013 and 0.914±0.031 in the 1×10-8, 1×10-7 and 1×10-6 mol/L β-E2 group, which were signifincatly higher than 0.428±0.010 in the blank control group and 0.426±0.010 in the solvent control group(all at P<0.05). The telomerase activity values (absorbance) were 0.711±0.015, 0.941±0.010 and 1.249±0.047 in the 1×10-8, 1×10-7 and 1×10-6 mol/L β-E2 group, which were higher than 0.535±0.013 in the blank control group and 0.543±0.013 in the solvent control group (all at P=0.000). The proliferantive values of the cells (absorbance) were significantly raised in the 1×10-8 mol/L β-E2 group compared with 1×10-7 and 1×10-6 mol/L β-E2 group (both at P=0.000), and no significnant difference was found in the proliferetive values between the blank control group and the solvent control group (P=0.718, 0.856). The apoptosis rates of the cells in the 1×10-8, 1×10-7 and 1×10-6 mol/L β-E2 group were lower than those in the the blank control group and the solvent control group (all at P=0.000), and there was no significant difference between the blank control group and the solvent control group (P=0.777). No obvious correlation was found between the HLECs preliferative values and hTERT mRNA expression levels or telomerase activity values (r=-0.299, P=0.278; r=-0.157, P=0.576). However, significantly negative correlations were seen between apoptosis rates and hTERT mRNA expression levels or telomerase activity values (r=-0.975, P=0.000; r=-0.981, P=0.000). Conclusions β-E2 can increase the activity of telomerase in human LECs, and high dose of β-E2 can inhibit apoptosis, but it dose not promote proliferation. Key words: Epithelial cells, lens; Estradiol; Telomerase; Cataract, age-related; Apoptosis; Proliferation; Cell, cultured; Cell line

Protein kinase B is required for follicle-stimulating hormone mediated beta-catenin accumulation and estradiol production in granulosa cells of cattle

Follicle-stimulating hormone regulation of ovarian estradiol (E2) production requires involvement of beta-catenin (CTNNB1), a transcriptional co-factor. In cultured granulosa cells (GC) of cattle, FSH treatment increased protein abundance of CTNNB1 as well as protein kinase B (AKT), a molecule known to regulate components of the CTNNB1 degradation complex. However, whether FSH induction of CTNNB1 is through direct modulation of AKT remains to be determined. To investigate specific contributions of AKT to CTNNB1 accumulation, GC were treated with insulin-like growth factor-I (IGF-I), a well-established AKT activator, in the presence or absence of FSH. Granulosa cells treated with FSH, IGF-I, and IGF-I plus FSH had increased CTNNB1 accumulation compared with controls (P≤0.02; n=6). E2 medium concentrations were greater (P=0.09; n=4) in FSH treated cells compared to controls (166 and 100±28pg/mL, respectively). Treatment with IGF-I and IGF-I plus FSH increased (P<0.01) E2 to comparable concentrations. Subsequently, GC treated with lithium chloride (LiCl), a pharmacological activator of AKT, provided a response consistent with IGF-I treated cells, as LiCl, FSH, and FSH plus LiCl increased CTNNB1 accumulation compared with non-treated controls (P≤0.03; n=3). In contrast, inhibition of AKT signaling with LY294002 suppressed the ability of FSH and IGF-I to regulate CTNNB1. Additionally, LY294002 treatment reduced FSH and IGF-I mediated E2 medium concentrations (P≤0.004). These results demonstrate that activation of AKT is required for gonadotropin regulation of CTNNB1 accumulation and subsequent ovarian E2 production.

Estradiol Elicits Proapoptotic and Antiproliferative Effects in Human Trophoblast Cells.

During the first trimester of pregnancy, appropriate regulation of estradiol (E2) is essential for normal placental development. Previous studies demonstrate that premature elevation in E2 concentrations can lead to abnormal placentation, but have not fully elaborated the mechanism of this effect in the first-trimester trophoblast. Our aim was to determine whether E2 elicits trophoblast cell death or inhibits proliferation. The first-trimester human cytotrophoblast cell line HTR-8/SVneo was cultured in phenol red-free medium containing charcoal-stripped serum and treated with 17beta-E2 at concentrations between 0 and 100 nM. TUNEL and invasion assays indicated that E2 significantly increased cell death and reduced cell invasion at 10 nM, and nuclear Ki67 expression revealed that it decreased cell proliferation at 1 nM. A similar effect on cell death was observed in first-trimester placental explants. The E2 antagonist fulvestrant blocked all effects of E2. Immunohistochemistry showed that protein expression of proapoptotic caspases 3, 8, and 9 increased at E2 concentrations of 25 nM and greater, whereas expression of antiapoptotic BCL2-alpha decreased at E2 concentrations of 10 nM and greater. Additionally, treatments with estrogen receptor (ER) alpha-specific and ERbeta-specific agonists at concentrations between 0 and 1000 nM indicated that only ERalpha mediates E2's effects, although immunohistochemistry and Western immunoblotting showed that HTR-8/SVneo cells and placental explants express both ERalpha and ERbeta. Taken together, these findings reveal the interplay between elevated serum E2 and apoptosis in the first trimester of pregnancy. These factors could be associated with pregnancy complications including infertility and uteroplacental insufficiency.

Estrogen regulation of microcephaly genes and evolution of brain sexual dimorphism in primates.

BackgroundSexual dimorphism in brain size is common among primates, including humans, apes and some Old World monkeys. In these species, the brain size of males is generally larger than that of females. Curiously, this dimorphism has persisted over the course of primate evolution and human origin, but there is no explanation for the underlying genetic controls that have maintained this disparity in brain size.ResultsIn the present study, we tested the effect of the female hormone (estradiol) on seven genes known to be related to brain size in both humans and nonhuman primates, and we identified half estrogen responsive elements (half EREs) in the promoter regions of four genes (MCPH1, ASPM, CDK5RAP2 and WDR62). Likewise, at sequence level, it appears that these half EREs are generally conserved across primates. Later testing via a reporter gene assay and cell-based endogenous expression measurement revealed that estradiol could significantly suppress the expression of the four affected genes involved in brain size. More intriguingly, when the half EREs were deleted from the promoters, the suppression effect disappeared, suggesting that the half EREs mediate the regulation of estradiol on the brain size genes. We next replicated these experiments using promoter sequences from chimpanzees and rhesus macaques, and observed a similar suppressive effect of estradiol on gene expression, suggesting that this mechanism is conserved among primate species that exhibit brain size dimorphism.ConclusionsBrain size dimorphism among certain primates, including humans, is likely regulated by estrogen through its sex-dependent suppression of brain size genes during development.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0398-x) contains supplementary material, which is available to authorized users.

The relationship between reproductive history and hormones and BRCA mutations

Recent studies report a possible role of BRCA genes in female reproduction, especially in regulation of estradiol (E2) levels by altering aromatase activity. This study aims to investigate the reproductive environment including reproductive history and hormone levels in women with and without BRCA gene (1 or 2) mutations.

Regulation of Estradiol and Progesterone Production by CRH-R1 and -R2 Is through Divergent Signaling Pathways in Cultured Human Placental Trophoblasts

CRH and its related peptides urocortins (UCN) have been identified in placenta and implicated to play pivotal roles in the regulation of pregnancy and parturition in humans. The objectives of present study were to investigate the effects of endogenous CRH and its related peptides in the regulation of steroid production in placenta. Placental trophoblasts were isolated from term placenta tissues and cultured for 72 h. Estradiol (E(2)) and progesterone (P(4)) contents in culture media were determined by radioimmunoassay. Treatment of cultured trophoblasts with CRH or UCNI antibody showed decreased E(2), whereas increased P(4) production. Treatment of cells with CRH receptor type 1 antagonist antalarmin or CRH receptor type 2 (CRH-R2) antagonist astressin-2b also decreased E(2) but increased P(4) production. Knockdown of CRH receptor type 1 or CRH-R2 cells showed a decrease in E(2) production and an increase in P(4) production. In CRH-R2 knockdown cells, CRH stimulated GTP-bound Gαs protein and phosphorylated phospholipase C-β3. Adenylyl cyclase and protein kinase A inhibitors blocked CRH-induced increased E(2) production but not decreased P(4) production. PLC inhibitor U73122 and protein kinase C inhibitor chelerythrine blocked the effects of CRH on E(2) and P(4) production in CRH-R2 knockdown cells. UCNIII, the specific CRH-R2 agonist, stimulated GTP-bound Gαi protein and phosphorylated phospholipase C-β3 expression. Both U73122 and chelerythrine blocked UCNIII-induced increased E(2) production and decreased P(4) production. We suggest that CRH and its related peptides might be involved in changes in the progesterone to estrogen ratio during human pregnancy.

Effects of dietary oxidized oil on laying performance, lipid metabolism, and apolipoprotein gene expression in laying hens

We studied the effects of dietary oxidized oils on serum lipid metabolic indices, estradiol level, and the gene expression of apolipoprotein B-100 and apolipoprotein VLDL-II in laying hens. Hy-Line Grey hens (280 ± 10 d old; average egg production, 90.0 ± 2.5%) were allotted to 1 of 4 dietary treatments, which were supplemented with 0 (control group), 1% (low oxidized group), 2% (moderately oxidized group), or 4% (highly oxidized group) thermally oxidized soybean oil. Each treatment contained 6 replicates, with 12 birds each. The feeding trial lasted for 30 d. Laying performance data were recorded weekly. Other indices were measured on d 0, 2, 6, 14, and 30 of the feeding trial. Hens in the moderately and highly oxidized groups had significantly lowered feed conversion ratios (P < 0.05). Those in the highly oxidized group also had decreased concentrations of serum very low density lipoprotein cholesterol on d 30 (P < 0.05) compared with the very low density lipoprotein cholesterol of hens in the moderately oxidized group. Hens in the moderately oxidized group had significantly increased expression of apolipoprotein B-100 (P < 0.05) from d 6 to 30. Consequently, hepatic triglyceride increased in this group on d 30 (P < 0.05). Serum triglyceride decreased in the moderately oxidized group on d 30 (P < 0.05), which may have been caused by the activation of peroxisome proliferator-activating receptor α. Serum estradiol levels were not significantly affected by oxidized oils at any time of measurement, but were significantly different between d 0 and 30 within the moderately oxidized group. This fact indicated that the effect of oxidized oils on apolipoprotein B-100 might partially be a cumulative result of the increasing secretion of estradiol. The results suggested that oxidized oil may affect the performance of laying hens through the regulation of apolipoproteins and estradiol.

DiurnalIn Vivoand RapidIn VitroEffects of Estradiol on Voltage-Gated Calcium Channels in Gonadotropin-Releasing Hormone Neurons

A robust surge of gonadotropin-releasing hormone (GnRH) release triggers the luteinizing hormone surge that induces ovulation. The GnRH surge is attributable to estradiol feedback, but the mechanisms are incompletely understood. Voltage-gated calcium channels (VGCCs) regulate hormone release and neuronal excitability, and may be part of the surge-generating mechanism. We examined VGCCs of GnRH neurons in brain slices from a model exhibiting daily luteinizing hormone surges. Mice were ovariectomized (OVX), and a subset was treated with estradiol implants (OVX+E). OVX+E mice exhibit negative feedback in the A.M. and positive feedback in the P.M. GnRH neurons express prominent high-voltage-activated (HVA) and small low-voltage-activated (LVA) macroscopic (whole-cell) Ca currents (I(Ca)). LVA-mediated currents were not altered by estradiol or time of day. In contrast, in OVX+E mice, HVA-mediated currents varied with time of day; HVA currents in cells from OVX+E mice were lower than those in cells from OVX mice in the A.M. but were higher in the P.M. These changes were attributable to diurnal alternations in L- and N-type components. There were no diurnal changes in any aspect of HVA-mediated I(Ca) in OVX mice. Acute in vitro treatment of cells from OVX and OVX+E mice with estradiol rapidly increased HVA currents primarily through L- and R-type VGCCs by activating estrogen receptor beta and GPR30, respectively. These results suggest multiple mechanisms contribute to the overall feedback regulation of HVA-mediated I(Ca) by estradiol. In combination with changes in synaptic inputs to GnRH neurons, these intrinsic changes in GnRH neurons may play critical roles in estradiol feedback.

Estrogen receptor α is expressed on the cell-surface of embryonic hypothalamic neurons

Although the biological activity of estrogen is generally mediated through nuclear estrogen receptors, a large body of evidence indicates that estrogen may also affect target cells upon binding to putative membrane estrogen receptors (mER) coupled to intracellular signaling cascades; however, no agreement has been reached on the nature and precise location of the putative estrogen receptor (ER) responsible for these rapid effects. In the present report we show that the expression of ERα is associated with the plasma membrane fraction of rat hypothalamic tissue at embryonic day 16. Moreover, our experiments extend these results to rat hypothalamic neurons in vitro showing that ERα can be detected from the cell exterior as a biotinylated cell-surface protein. We have also shown that the mERα is under regulation of estradiol, and the ERα agonist, 4,4′,4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol, induced extracellular-signal-regulated kinase signaling in a dose-dependent manner and in a time-course not compatible with genomic actions, supporting the notion of a membrane-initiated phenomenon.

Follicular fluid nitric oxide (NO) concentrations in stimulated cycles: the relationship to embryo grading

The microenvironment of the ovarian follicle is vital for normal oocyte development, folliculogenesis, and timely ovulation. We investigated the concentration of nitric oxide (NO) in follicular fluid, collected during oocyte retrieval after in-vitro fertilization and embryo transfer (IVF-ET) and its relationship to oocyte and embryo grading. A total of 53 follicular fluid samples were obtained from 15 patients undergoing IVF-ET program, oocyte retrieval by transvaginal guidance was per formed approximately 34-35 h after the hCG administration in stimulated cycles. Using a modified grading system the samples were divided in Group 1 with very few fragments in the cytoplasm with equal size blastomeres (best embryos) and Group 2 with significant or severe fragmentation or blastomeres of distinctively unequal size. Follicular NO was measured as nitrite/nitrate. The mean concentration of NO follicular fluid is significantly higher in Group 2 than in Group 1 (57.54 +/- 12.67 nmol/mg vs. 42.43 +/- 16.32 nmol/mg). Using the correlation analysis, we observed a direct correlation between follicular NO and embryo grading (r = 0.61; P < 0.001) and an inverse correlation between follicular NO and serum 17beta-estradiol (r = -0.28; P < 0.05). High levels of NO in human follicles may be detrimental. The inverse correlation found between NO and serum concentrations of 17beta-estradiol may be explained as a regulation of estradiol on maturation process of the oocytes and embryos in stimulated cycles through NO mediation.

Expression of aromatase and estrogen sulfotransferase in preinvasive and invasive breast cancer

Intratumoral estradiol levels in postmenopausal women with breast cancer are thought to be mainly regulated by the aromatase-mediated conversion from androgens and estrogen sulfotransferase (EST)-mediated reduction of bioavailability. While in invasive breast cancer (IBC) the role of both enzymes has been extensively studied and has led to the use of aromatase inhibitors as a key therapeutic strategy, comparably little is still known about their role in the local regulation of estradiol in ductal carcinoma in situ (DCIS). We have performed immunohistochemistry to investigate the expression of aromatase and sulfotransferase in custom-made breast cancer tissue arrays containing 96 samples of pure DCIS and in 104 tumor biopsies which contain both, DCIS and invasive components. We found that aromatase was equally detectable in epithelial components of both, DCIS and IBC (P = 0.884, Chi square test). However, stromal aromatase expression was significantly higher in IBC compared to adjacent DCIS components (P = 0.034, Chi square test). Whereas no significant difference was observed for epithelial aromatase expression in high versus non-high grade DCIS (P = 0.735 Chi square test), epithelial EST levels were found to be significantly down-regulated in high-grade DCIS compared to non-high grade cases (P = 0.042). We have demonstrated the presence of both aromatase and EST in malignant epithelium and adjacent stromal fibroblasts in DCIS. Lower stromal aromatase expression in preinvasive breast cancer and lower EST levels in high-grade DCIS suggest that the net effect of intratumoral estradiol (E2)-modulating enzymes results in lower local E2 levels in earlier stages of breast tumorigenesis.

Reproductive Experience Reduces Circulating 17β-Estradiol and Prolactin Levels during Proestrus and Alters Estrogen Sensitivity in Female Rats

The reproductive experiences of pregnancy, parturition, and lactation affect a range of neural and endocrine processes after the end of lactation. In women, previous parity results in reduced circulating prolactin (PRL) and androgen levels years after giving birth. Reductions in PRL secretion also occur in reproductively experienced, female rats. In the present study we examined the status and regulation of estradiol (E(2)) and PRL during the reproductive cycle after reproductive experience. These hormones regulate one another and have been implicated in a number of disease and aging processes. Using a rat model, the patterns of E(2) and PRL secretion, pituitary PRL content, and estrogen receptor alpha expression were characterized from 1200-1800 h on proestrus in age-matched, primiparous and nulliparous animals. The possible effect of parity on estrogen sensitivity was then examined by challenging nonlactating, ovariectomized, age-matched, multiparous and nulliparous rats with estradiol benzoate (EB; 0, 1, 5, 25, and 125 microg/kg) and measuring PRL responses 24 and 48 h later. Previous parity resulted in modest, yet significant, reductions in E(2) and PRL levels on proestrus, a limited increase in pituitary estrogen receptor alpha expression, and a significant shift in estrogen sensitivity, as measured by EB-induced PRL secretion. Nulliparous animals were more sensitive than multiparous rats to the two lower doses of EB, whereas multiparous animals were more responsive to the highest EB dose. These unique parity-induced alterations in the female's endocrine state that persist beyond lactation may impact a multitude of estrogen-mediated processes over the female's adult life span.

The COMT val158met Polymorphism Is Associated with Early Pubertal Development, Height and Cortical Bone Mass in Girls

Estrogens are involved in accretion of bone mass during puberty. Catechol-O-Methyltransferase (COMT) is involved in the degradation of estrogens. In this cross-sectional study we investigated associations between the COMT val158met polymorphism, which results in a 60-75% difference in enzyme activity between the val (high activity = H) and the met (low activity = L) variant, and skeletal phenotypes in 246 healthy pre/early pubertal girls. Girls with COMT(LL) were 5.4 cm taller than COMT(HH) girls. Dual x-ray absorptiometry showed higher values of bone mineral content (BMC), and larger areas of total body, femur and spine in COMT(LL). Cortical BMC, measured by peripheral quantitative computerized tomography in the tibia, was 9.8% higher in COMT(LL) compared with COMT(HH). This was due to a larger cortical cross sectional area while the cortical volumetric bone mineral density was not associated with COMT genotype. COMT(LL) girls had higher serum levels of free estradiol and insulin like growth factor. Regression models indicated that COMT genotype exerted effects on skeletal growth mainly via a regulation of free estradiol, resulting in an affected pubertal development (Tanner staging). We propose that the COMT(LL) genotype results in higher free estradiol levels and earlier pubertal development, leading to an increased skeletal growth in pre/early pubertal girls. Possible consequences for the adult skeleton however can be determined only after cessation of growth.