Human Chorionic Gonadotropin Secretion Research Articles

Calcitriol affects hCG gene transcription in cultured human syncytiotrophoblasts

BackgroundIn pregnancy, maternal serum concentrations of calcitriol significantly rise as a result of increased renal and placental contribution in order to assure calcium supply for the developing fetus. Considering that placenta is a site for vitamin D activation, and the versatility and potency of calcitriol, it is feasible that this hormone participates in fetal/placental development and physiology. In the present work we studied calcitriol actions upon human chorionic gonadotropin (hCG) secretion and expression in cultured trophoblasts, as well as vitamin D receptor (VDR) and CYP27B1 immunolocalization in placental villi.MethodsQuantification of hCG in culture media was performed by immunoassay. Expression studies were carried out by real time PCR. Analysis of CYP27B1 and VDR localization in placental slides were performed by immunohistochemistry. Statistical significance was established by one way ANOVA using Tukey test for comparisons.ResultsCalcitriol regulated hCG in a time-dependent manner: at 6 h the secosteroid stimulated hCG, whereas longer incubations (24 h) showed opposite effects. Interestingly, calcitriol stimulatory effects on hCG were accompanied by an increase in intracellular cAMP content and were abolished by pre-incubation of the cells with a selective protein kinase A inhibitor. Immunohistochemical techniques showed differential VDR localization in the syncytiotrophoblast layer or in the vascular smooth muscle cells depending on the epitope to which the antibodies were raised (specific for the carboxy- or amino-terminal regions, respectively). CYP27B1 was immunolocalized in the syncytiotrophoblast layer of placental villi.ConclusionThe presence and location of the vitamin D activating enzyme CYP27B1 as well as the specific receptor for vitamin D were shown in placental sections. The latter, together with findings demonstrating specific effects of calcitriol acting through the VDR and the cAMP/PKA signaling pathway upon hCG expression and secretion, indicate that there is a functional vitamin D endocrine system in the placenta, and recognize calcitriol as an autocrine regulator of hCG.

Noise magnetic fields mitigates the inhibition of secretion function of primary human villous trophoblasts induced by 50 Hz magnetic fields

To explore the effects of 50 Hz sinusoidal magnetic fields (MF) on secretion function of primary human villous trophoblasts in vitro, and the interference effect of "noise" MF. The trophoblasts were isolated from human villus by trypsin digestion and incubated in DMEM medium.Then the trophoblasts were exposed to 0.4 mT 50 Hz MF and/or "noise" MF respectively for different durations. Each exposure group was matched with one control group which was from the same villus and cultured with the same condition except the MF exposure. The concentrations of human chorionic gonadotropin (HCG) and progesterone in the culture medium were measured by immunofluorescence. Statistical significance of differences between means was determined by one way-ANOVA with P<0.05 considered significant. 50 Hz MF inhibited the HCG and progesterone secretion significantly when exposure for 72 h (compared with control group, P<0.05). There was no significant change of HCG and progesterone secretion when trophoblasts were exposed to 0.4 mT "noise" MF within 72 h (compared with control group, P>0.05). However, by superimposing the "noise" MF, the inhibition of HCG and progesterone secretion of trophoblasts induced by 50 Hz MF was eliminated. The exposure to 50 Hz MF for long period could inhibit trophoblasts secreting HCG and progesterone, and the "noise" MF with the same intensity could eliminate the effects induced by 50 Hz MF.

Reduction of human chorionic gonadotropin beta subunit expression by modified U1 snRNA caused apoptosis in cervical cancer cells

BackgroundSecretion of human chorionic gonadotropin, especially its beta subunit by malignant trophoblastic tumors and varieties of tumors of different origin is now well documented; however the role of hCG in tumorogenesis is still unknown.ResultsThis study documents the molecular presence of human chorionic gonadotropin beta subunit in uterine cervix cancer tissues and investigates a novel technique to reduce hCGβ levels based on expression of a modified U1 snRNA as a method to study the hormone's role in biology of human cervical cancer cells cultured in vitro. The property of U1 snRNA to block the accumulation of specific RNA transcript when it binds to its donor sequence within the 3' terminal exon was used. The first 10 nucleotides of the human U1 snRNA gene, which normally binds to the 5'ss in pre-mRNA were replaced by a sequence complementary to a 10-nt segment in the terminal exon of the hCGβ mRNA. Three different 5' end-mutated U1 snRNA expression plasmids were tested, each targeting a different sequence in the hCGβ mRNA, and we found each one blocked the expression of hCGβ in HeLa cells, a cervix carcinoma cell line, as shown by immunohistochemistry and qRT-PCR. Reduction of hCGβ levels resulted in a significantly increased apoptosis rate with almost 90% of cells transfected with modified anti-hCGβ U1 snRNAs showing morphological changes characteristic of the apoptotic process.ConclusionThese data suggest that human chorionic gonadotropin beta subunit may act as a tumor growth-stimulating factor.

Time-dependent action of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) and its metabolite DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) on human chorionic gonadotropin and progesterone secretion

Explants of human placenta were used to study the effects of two isomers of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) [p,p′-DDT and o,p′-DDT] and their DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) metabolites [p,p′-DDE and o,p′-DDE] on the secretion of progesterone and human chorionic gonadotropin (hCG). Explants were treated with 1, 10, 100 or 1000 ng/ml of each compound for 24 h or 72 h. We found opposite effects (stimulatory after short-term and inhibitory after long-term exposure) of all compounds on progesterone secretion. However, both short- and long-term exposure to all investigated compounds caused decreased hCG secretion. In conclusion, we suggest the existence of a local axis between steroid hormones and hCG in placenta. DDT (which has estrogenic properties) increases progesterone secretion and consequently decreases hCG secretion. After long-term exposure, the low level of hCG is insufficient to stimulate progesterone.

Effects of 50 Hz magnetic fields exposure on secretion of primary human villous trophoblasts

To explore the possible effects of 50 Hz magnetic fields (MF) exposure on HCG and progesterone secretion of human villous trophoblasts in vitro. The trophoblasts were isolated from human villus by trypsin digestion and incubated in DMEM medium. Then the trophoblasts were exposed to 0.2 mT, 0.4 mT 50 Hz MF for 6 h, 12 h, 24 h, 48 h and 72 h, respectively. Each exposure group was matched to one control group which was from the same villus and cultured with the same condition except the 50 Hz MF exposure. The concentration of human chorionic gonadotropin (HCG) and progesterone in the culture medium was detected by electrochemiluminescence immunoassay. Statistical significance of differences between means was determined by one way-ANOVA with P < 0.05 considered significant. Exposure of trophoblasts to 50 Hz MF at 0.2 mT intensity within 72 h did not affect the secretion level of HCG and progesterone (compared with blank control, P > 0.05). There was also no significant change of the secretion level of HCG and progesterone when trophoblasts were exposed to 0.4 mT 50 Hz MF within 48 h (compared with blank control, P > 0.05). However, 50 Hz MF inhibited the HCG and progesterone secretion significantly with exposure for 72 h (compared with blank control, P < 0.05). The exposure to 50 Hz MF for long period could inhibit trophoblasts excreting the HCG and progesterone, and the threshold intensity may be between 0.2 mT and 0.4 mT.

Hourly human chorionic gonadotropin secretion profiles during the peri-implantation period of successful pregnancies

To characterize the hourly profiles of hCG secretion in blood during conceptive cycles that ended in successful pregnancy. Prospective study. University fertility clinic and research laboratories. Healthy spontaneously ovulating women with regular menses, no history of infertility, and either no male partner or an azospermic partner. Frequent blood samples were collected daily from 11 spontaneously ovulating women during 11 cycles of artifical insemination with donor semen. The concentrations of hCG, LH, and FSH were measured in the blood by immunoassay. The concentration of hCG in the frequent blood samples and the rate that the concentration of hCG changed during the period of frequent sampling. For the conceptive cycles resulting in successful pregnancies analyzed, hourly hCG concentrations were observed to increase in a consistent nonpulsatile manner. These data provide the first characterization of the hourly secretion profile of hCG in early pregnancy as well as provide further evidence that individual daily blood samples are sufficient for the accurate assessment of pregnancy.

Le choriocarcinome infantile : une tumeur exceptionnelle et curable

Choriocarcinoma is a malignant growth of trophoblastic cells characterized by secretion of human chorionic gonadotropin (hCG). Infantile choriocarcinoma is a very rare tumor, which is a complication of gestational choriocarcinoma and usually had very poor prognosis before chemotherapy was used. We report 1 new case as well as a review of the literature since 1945. Our case report describes the successful treatment by chemotherapy of a newborn with cerebral metastasis. Several features are important: Infantile choriocarcinoma occurs in infants aged 0 to 6 months. Anemia, hepatomegaly and hemorrhagic syndromes are the main symptoms with sometimes cerebral, cutaneous or ear-nose and throat localisations. But diagnosis can be difficult when clinical symptoms are poor. The main diagnostic criterion is a very high plasmatic or urinary level of hCG or β-hCG in the newborn. Histological pattern is not mandatory for diagnosis. Thoracoabdominal CT scan and cerebral MRI are necessary to find metastases. Recommanded treatment is chemotherapy and surgery is discussed when a tumoral residue remains. Post-treatment surveillance is based on clinical and radiological examination as well as negativation of β-hCG. Choriocarcinoma occuring simultaneously in mother and child have been reported. Therefore it is necessary to assay maternel serum β-hCG when infantile choriocarcinoma is disclosed and to assay serum β-hCG in the newborn when the mother has gestational choriocarcinoma. Infantile choriocarcinoma is a very chemosensitive tumor and is thereby potentially curable. Early diagnosis is the most important prognostic factor.

HCG Secretion in Human Choriocarcinoma JAR Cells is MAPK but not Stat3 Dependent: Contributions of TNFα and IL-1β to Inflammation-induced hCG Secretion

Inflammatory mediators play critical physiologic roles throughout the course of normal pregnancy. At the same time, uncontrolled inflammation appears to have an adverse affect on pregnancy outcome. Thus, a crucial task of reproductive immunology is to define the mechanisms through which inflammation is controlled at the maternal-fetal interface. We examined the signaling pathways activated in the human choriocarcinoma cell line, JAR, in response to an in vitro model of an inflammatory challenge. We incubated JAR cells with medium from peripheral blood mononuclear cells (PBMC) that had been activated with either LPS or PHA. Conditioned medium from each experimental model induced MAP kinase and Stat3 phosphorylation as well as human chorionic gonadotropin (hCG) secretion from JAR cells. hCG secretion could be blocked by pharmacologic inhibition of MAP kinase but not by inhibition of Stat3 using an siRNA approach. The MAPK activators IL-1beta and TNFalpha both induced hCG secretion from JAR cells, but not the Stat3 activators IFN-gamma and IL-6. Furthermore, hCG secretion induced by conditioned media could be blocked by IL-1 receptor antagonist. We conclude that inflammation at the maternal-fetal interface may involve complex webs of regulatory and counter-regulatory mechanisms that involve multiple cytokines and at least two major, independent cell-signaling systems.

Endocrinology of pregnancy: Consequences for the diagnosis and treatment of pregnancy disorders

Placental human chorionic gonadotropin and corpus luteum secretion of progesterone and oestradiol are the main endocrine events at the beginning of pregnancy, whilst the luteo-placental shift is an important step during the later stages. Progesterone not only affects decidualisation, but is the major immunological determinant and controls uterine contractibility and cervical competence. These properties all contribute considerably towards the correct development of pregnancy and delivery at term.

Addendum to: Yoshida Y (2005) Secretion of human chorionic gonadotropin in early pregnancy. Med Mol Morphol 38:104–111

Addendum to: Yoshida Y (2005) Secretion of human chorionic gonadotropin in early pregnancy. Med Mol Morphol 38:104–111

Sphingosine-1-phosphate inhibition of placental trophoblast differentiation through a Gi-coupled receptor response

The failure of placental trophoblasts to differentiate properly is thought to play an important role in the cause of pregnancy disorders such as preeclampsia. We looked at the effects of the bioactive lipid sphingosine-1-phosphate (S1P) on the differentiation of primary human cytotrophoblasts (CTs) into syncytiotrophoblasts (STs) in culture. We found that S1P inhibited CT differentiation measured by human chorionic gonadotropin (hCG) secretion and the expression of placental alkaline phosphatase but had no effect on their fusion into multinucleated syncytialized cells. G-protein-linked S1P receptors 1, 2, and 3 were found in CTs by reverse transcriptase-polymerase chain reaction, and receptor 1 was found by Western blot analysis. Disruption of G(i) signaling with pertussis toxin reversed the inhibitory effects of S1P. S1P reduced intracellular cAMP, and the addition of 8-bromo-cAMP reversed S1P inhibition of hCG secretion. Therefore, we suggest that S1P inhibits the differentiation of CTs into STs through G(i)-coupled S1P receptor interaction(s), leading to the inhibition of adenylate cyclase and reduced production of intracellular cAMP. This is the first reported effect of S1P on placental trophoblast function.

Secretion of human chorionic gonadotropin in early pregnancy

Remarkable secretion from the syncytial trophoblast of chorionic villi was observed in early pregnancy. Histology and histochemistry revealed many cytoplasmic protrusions containing numerous secretory granules, which were of basophilic glycoprotein in nature. Also, immunohistochemistry proved that these were human chorionic gonadotropin (hCG). Electron microscopy clarified the overall secretory process, which started with the production of small granules in the Golgi complex; then, the granules migrated toward the cell surface, increasing their size by fusing with each other, and gathered in cytoplasmic protrusions, then liquefied to be liberated by a mode of exocytosis into the maternal bloodstream (intervillous space). This remarkable hCG secretion, morphologically represented by the many cytoplasmic protrusions containing numerous secretory granules, arose synchronously on the surface of almost all chorionic villi. This phenomenon was limited to the eighth and ninth weeks of gestation, concurring with the maximal hCG concentration of maternal blood serum during pregnancy.

Human chorionic gonadotropin (hCG) may be a marker of systemic oxidative stress in normotensive and preeclamptic term pregnancies

Objectives: In vitro studies on placental function have revealed interactions between levels of secretion of human chorionic gonadotropin (hCG) by trophoblastic cells and oxidative stress generated by hydrogen peroxide (H 2O 2). Here, we have examined the relationship between maternal levels of hCG and H 2O 2 in vivo in term pregnancies with and without preeclampsia. Design and methods: We measured serum levels of hCG and H 2O 2 in twenty preeclamptic and twenty normotensive term pregnant women (controls), using an enzymatic immunoassay and an electrochemical method, respectively. Results: Higher levels of serum hCG and H 2O 2 were observed in patients with preeclampsia in comparison to controls. A significant positive correlation between serum hCG concentration and H 2O 2 production was found. Conclusion: Our results show that: (1) systemic hCG levels are correlated with an oxidative stress state in term pregnant women with preeclampsia and (2) circulating hCG may be a monitoring tool of oxidative stress during pregnancy.

Induction of zinc transporters by forskolin in human trophoblast BeWo cells

During pregnancy, the zinc level in fetal serum is up to two-fold higher than that in the maternal serum at the end of pregnancy, but the mechanism of zinc release from the placenta into fetal circulation is not well understood. In this study, we determined the expression profiles of zinc transporters in human trophoblast BeWo cells, a representative human trophoblast cell line. Zn transporter 1–8 (ZnT1–8), Zrt/IRT-like protein 1 and Zn transporter-like transporter 1 were detected in BeWo cells by reverse transcription-polymerase chain reaction. Forskolin (FK) is a representative inducer of differentiation of BeWo cells cytotrophoblast into syncytiotrophoblast. Treatment of BeWo cells with FK resulted in morphological changes of BeWo cells into syncytiotrophoblast cells and secretion of human chorionic gonadotropin, which is a characteristic of syncytiotrophoblast cells. Treatment of BeWo cells with FK elevated ZnT1, 2 and 4 mRNA levels. These data about expression profiles of ZnTs may be useful for further investigation of placental biology.

Hyperthyroidism due to secretion of human chorionic gonadotropin in a patient with metastatic choriocarcinoma

A 26-year-old pregnant woman presenting with repeated episodes of vaginal bleeding, weight loss, and shortness of breath was diagnosed with choriocarcinoma with metastases to both lungs. Chorionic gonadotropin levels (hCG) were >2.5 x 10(6)mU/mL. Consistent with hCG-induced subclinical hyperthyroidism, she had a suppressed TSH of 0.037 mU/L (0.49 - 4.67), a T4 of 18.1 microg/dL (4.9 - 10.7), and T3 of 136 ng/dL (45 - 137). Chemotherapy with a combined regimen with etoposide, methotrexate, and dactinomycine was started. The initial course was complicated by urosepsis with respiratory distress requiring endotracheal intubation for 3 days. She then improved rapidly, and her thyroid function tests were within normal limits by day 12. Six months later, after ten cycles of chemotherapy, the patient was in remission without signs of residual tumor or hCG-induced paraneoplastic activity.

Secretion and excretion of human chorionic gonadotropin during early pregnancy

To characterize the profiles of human chorionic gonadotropin (hCG) secretion in blood and its subsequent excretion in urine during conceptive cycles that ended in successful pregnancy and in spontaneous abortion. A prospective study. University fertility clinic and research laboratories. Healthy, spontaneously ovulating women with regular menses, no history of infertility, and either no male partner or an azoospermic partner. Blood and urine samples were collected daily from 63 spontaneously ovulating women during 167 cycles of artificial insemination (AI) with donor semen; hCG concentrations were measured in blood and urine, and luteinizing hormone (LH) and follicle-stimulating hormone (FSH) concentrations were measured in blood by immunoassay. Fecundity, the day of ovulation, the day of hCG detection, and the concentration of hCG on the day of detection in blood and urine. In 62 conceptions detected, 14 resulted in clinical spontaneous abortion (CAB) and 8 resulted in early pregnancy loss (EPL). When successful pregnancies and pregnancy losses were compared, no significant differences existed between the days of hCG appearance in serum or in urine, the concentrations of hCG on the day of detection, or the incremental change in hCG concentration on the day of detection. These data validate the use of urinary hCG as a biomarker for assessing peri-implantation pregnancy events.

The extent and variability of effects of culture conditions on the secretion of human chorionic gonadotrophin and interleukin-6 by human, term placental explants in culture

Culture of explants derived from third trimester human placenta is used in a range of contexts as an experimental model that retains tissue architecture. This study aimed to explore the variability between, and within, individuals of secretion by explants of human chorionic gonadotrophin (hCG) and interleukin-6 (IL-6). Standard culture medium contained hydrocortisone, insulin, retinoic acid and serum. Under these conditions explants displayed significant differences in the time-course and extent of hCG secretion. Peak hCG secretion varied between 1.19 and 242 mIU/mg protein/h (coefficient of variation (CV) = 111%) and could occur between days 4 and 7 of culture. hCG secretion was more variable if explant protein was <400 μg. Unadjusted day 7 hCG secretion showed marked variation: intra-placental CV = 15%, inter-placental CV = 86%. When day 7 hCG secretion was standardised by day 6 secretion, intra-placental CV was 6.9%, inter-placental CV was 4.0%. When this standardisation was applied, hCG secretion during day 7 of culture was not affected by removal of hydrocortisone, insulin or serum from the medium or by the addition of tumour necrosis factor-α (TNF-α). The secretion of IL-6 during day 7 of culture (standardised by taking natural logarithms) was increased markedly by the addition of TNF-α but unaltered by removing hydrocortisone, insulin or serum. Thus, we have shown that although variable, secretion by placental explants can be used to investigate how placental tissue adapts to different culture conditions. However, explants of the same protein content may have markedly different secretory properties.

Cutaneous Metastasis of Choriocarcinoma : A Case Report

Choriocarcinoma is one of the malignant tumors of trophoblastic cells characterized by the secretion of human chorionic gonadotrophin (hCG) (1-3). Cutaneous metastasis is a rare presentation of choriocarcinoma but a poor prognostic sign because it is associated only with widespread disease (3-5). A 52-yr-old female complaining of dyspnea for 2 months, presented with fingertip sized erythematous nodules on the left side of the neck and the right side of the upper back of 1 month duraton. She has suffered from Behçet's disease since 1999. Microscopic examination of a nodule of upper back demonstrated biphasic pattern of cytotrophoblasts and hCG-positive syncytiotrophoblasts, and the typical histologic features of choriocarcinoma. She was referred to the gynecological oncology department. After 17 cycles of combination chemotherapy, the serum hCG level has fallen from 700,000 to under 2.0 mIU/mL and the skin lesions have almost disappeared. However, after 3 months, total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed due to elevated serum hCG level (4,447.7 mIU/mL), and she is scheduled to receive post-operative adjuvant chemotherapy.

Expression of cFABP and PPAR in trophoblast cells: effect of PPAR ligands on linoleic acid uptake and differentiation

Throughout gestation, fetal growth depends, in part, on placental transfer of maternal essential fatty acid (EFA) and long-chain polyunsaturated fatty acid. All fatty acid (FA) can cross lipid bilayer by simple diffusion, such as those in the syncytiotrophoblasts, the multinucleated, terminally differentiated trophoblast cells. The trophoblasts differentiation process is accompanied by an increase of human chorionic gonadotropin (hCG) secretion and an inhibition of Human Achaete-Scute Homologue-2 expression (Hash-2). Furthermore, a number of FA-binding proteins (FABPs) have been identified in membrane and cytoplasm of mammalian cells, which are thought to facilitate the transfer of FA across membranes and their intracellular channeling. Thus, the aim of this study was to investigate the implication of cFABPs in linoleic acid (LA) uptake by human trophoblast cells according to differentiation. Moreover, since peroxisome proliferator-activated receptor (PPARs) regulate the expression of cFABP and play an important role in trophoblast cells differentiation, the effects of PPARs ligands are verified on cFABP expression and differentiation. Herein, we reported the increase of the expression of liver and heart FABP (L- and H-FABP) upon differentiation of trophoblast cells, an inhibition of PPARα and β, while PPARγ levels remains unchanged. The nonselective peroxisome-proliferating agents, bezafibrate and LA, impaired trophoblast differentiation, and reduced L- and H-FABP expression. Furthermore, cobalt, a chemical agent known to mimic hypoxia, inhibits trophoblast cells differentiation and diminishes H-, L-FABP and PPARs expression. Finally, both treatments show no influence on LA uptake by trophoblast cells. In conclusion, this study showed that there is no correlation between the expression of H- and L-FABP and LA uptake by trophoblast cells and that bezafibrate and LA greatly impaired trophoblast cells differentiation.

RNA interference-induced reduction in CD98 expression suppresses cell fusion during syncytialization of human placental BeWo cells

The physiological importance of CD98 surface antigen in regulating placental trophoblast cell fusion has been studied in a cell model of syncytialization (the cytotrophoblast cell line BeWo following increased intracellular cAMP by forskolin treatment) using RNA interference. CD98 protein abundance (determined by Western blot) was decreased by 40–50% following double-stranded small interfering RNA transfection. Cell fusion (determined by quantitative flow cytometry) was similarly inhibited and human chorionic gonadotropin secretion was suppressed. These findings show that CD98 is involved in the process of cell fusion necessary for syncytiotrophoblast formation.