Salivary unconjugated estriol levels in normal third trimester pregnancy - direct correlation with serum levels

A radioimmunoassay for salivary unconjugated estriol concentration during the third trimester of normal pregnancy is described. The performance characteristics of the method were established by determining the non-specific binding, the blank value of the endogenous estriol free ("stripped") saliva, the recovery experiment and intra- and interassay coefficient of the variations. The corresponding serum samples were also analyzed by the same method. An excellent correlation was found between salivary and serum estriol concentrations.     

孕中期双胎妊娠与单胎妊娠孕妇血清AFP与F-β-Hcg水平的比较

目的：检测双胎妊娠孕中期孕妇血清甲胎蛋白（AFP）和人绒毛膜促性腺激素游离B亚基（F-β-hCG）的水平,探索双胎妊娠时孕妇血清学筛查用于Down＇s胎儿高风险评估的AFP、F-β-hCG界定值。方法：收集双胎妊娠129例,孕中期（15～2l周）采集孕妇静脉血,用时间分辨荧光免疫分析技术测定血清AFP和F-β-hCG的浓度,并于分娩后随访,确定胎儿有无异常。另选2603例胎儿无异常的单胎妊娠作对照组。结果：129例双胎妊娠孕妇血清AFP浓度的中位教为98.98ng／ml,F-β-hCG浓度的中位数为32.20ng／mt;2603例单胎妊娠孕妇血清AFP和F-β-hCG浓度的中位数分别为52.15ng／ml和13.00ng／mt。双胎妊娠孕妇血清AFP和F-β-hCG的水平均明显高于对照组（P均〈0.01）。结论：鉴于双胎妊娠孕妇血清AFP和F-β-hCG水平明显升高,双胎妊娠的产前唐氏筛查风险评估时应引入正常双胎妊娠的AFP、F-β-hCG值。     

Level of alpha-fetoprotein in maternal serum before and after chorionic villus sampling

To evaluate incidence and severity of feto-maternal transfusion post-chorionic villus sampling (CVS), maternal serum AFP (MSAFP) were determined for 88 patients before and 15 minutes after CVS. To know whether MSAFP elevation could have clinical implications, a questionnaire was sent to the patients researching if they have had haemorrhages, temperature, spontaneous abortion or premature delivery in the period post CVS. Results of the present study indicate that 44.7% of patients present MSAFP significative elevation (greater than or equal to 8 micrograms/l), a variable elevation (from 8 to 423 micrograms/l). There is no relation between MSAFP elevation and unfavourable events post CVS.     

A test of maternal human chorionic gonadotropin during pregnancy as an adaptive filter of human gestations

The risk of abnormalities and morbidity among live births increases with advanced maternal age. Explanations for this elevated morbidity invoke several maternal mechanisms. The relaxed filter stringency (RFS) hypothesis asserts that mothers, nearing the end of their reproductive lifespan, reduce the stringency of a screen of offspring quality in utero based on life-history traits of parity and interbirth interval (IBI). A separate line of research implicates human chorionic gonadotropin (hCG) during pregnancy as a signal of offspring quality. We test the RFS hypothesis directly by examining whether the difference in gestational hCG across consecutive live births varies positively with the mother''s number of previous live births but inversely with her most recent IBI. We applied multivariable regression methods to a unique dataset of gestational hCG for over 500 000 live births from 2002 to 2007. The difference in gestational hCG across mothers'' consecutive live births varies positively with both mothers'' parity and IBI. These associations remain similar among older mothers (35+ years). Findings support the RFS hypothesis for the parity expectation but not for the IBI expectation. Further evidence for the RFS hypothesis among contemporary human gestations would have to invoke screening mechanisms other than hCG.     

The secretory patterns of relaxin and human chorionic gonadotropin in human pregnancy

Relaxin and human chorionic gonadotropin (hCG) were simultaneously determined in the same serum samples obtained from pregnant women. Although the secretory pattern of relaxin, in general, appeared to parallel that of hCG during human pregnancy, several discrepancies were discerned in the secretory patterns of the two hormones. The mean hCG concentration significantly differed between weeks 4-7 and 8-11 of pregnancy, but the mean relaxin concentration did not. The mean relaxin concentration began to decrease at weeks 16-19 whereas that of hCG did so at weeks 12-15. The mean relaxin concentration at weeks 4-7 was significantly higher than that at weeks 24-27, though there was no significant difference between the mean hCG concentrations in the two periods. These differences in the secretory pattern of relaxin from that of hCG indicate that relaxin secretion in pregnancy is not determined only by the circulating level of hCG. The responsiveness of the corpus luteum of pregnancy to hCG stimulation of relaxin secretion may vary as a function of the age of the corpus luteum, and this may partially account for the differences between the secretory pattern of relaxin and that of hCG observed in the present study.     

Subcellular localization of intracellular forms of human chorionic gonadotropin in first trimester placenta

To determine the subcellular sites for synthesis and processing of human chorionic gonadotropin subunits in cells, first trimester placental cells were fractionated subcellularly on sucrose density gradients. Analysis of the subcellular fractions by immunobinding techniques revealed that the rough endoplasmic reticulum-rich fraction contained only intermediates having high-mannose oligosaccharides, but the Golgi-rich fraction contained not only intermediates but also mature forms which were resistant to endoglycosidase H but sensitive to neuraminidase. These results show that human chorionic gonadotropin subunits are synthesized in the rough endoplasmic reticulum as forms containing high-mannose oligosaccharides, and their maturation occurs in the Golgi apparatus by trimming with endogenous glycosidases. They are then modified by addition of complex oligosaccharides and terminal sialic acid through glycosyltransferases.     

Role of calcium in secretion of chorionic gonadotropin by first trimester human placenta.

The role of calcium in regulation of secretion of human chorionic gonadotropin (hCG) by first trimester human placental minces in vitro has been investigated. Depletion of calcium in the medium by addition of EGTA resulted in a drastic decrease in the levels of immunoreactive hCG in the medium with consequent of accumulation of hCG in the tissue. Addition of A 23187 which is a calcium ionophore resulted in a dose dose dependent increase in the hCG in the medium and this stimulatory response could not be observed in the absence of calcium. Use of lanthanum (a calcium antagonist) in place of calcium in the medium used resulted in a significant decrease in the levels of hCG in the medium. Addition of veratridine (a sodium channel activator) stimulated hCG secretion in a dose dependent manner. These results suggest that calcium is essential for normal secretion of hCG by human placenta.     

Overexpression of human chorionic gonadotropin causes multiple reproductive defects in transgenic mice

Human CG is a pregnancy marker secreted by the placenta, and it utilizes the same receptors as does LH. Human CG is a heterodimer, and its subunits are expressed in tissues other than placenta. Similarly, LH/hCG receptors are also expressed in multiple tissues; however, the physiological significance of this expression is unknown. Free hCGbeta is efficiently secreted in vitro in transfected cells and is highly expressed in many human cancers; however, the biological effects of free hCGbeta in vivo are unknown. To study in vivo consequences of elevated levels of free hCGbeta and hCG dimer in both male and female reproductive physiology, we used mouse metallothionein 1 promoter to generate multiple lines of transgenic mice that overexpressed either one or both subunits of hCG. Although mice expressing the glycoprotein hormone alpha subunit are normal and fertile, both male and female transgenic mice overexpressing only the hormone-specific hCGbeta subunit are infertile. The hCGbeta subunit-expressing transgenic female mice progressively develop cystic ovaries, whereas the male transgenic mice are infertile but otherwise are not phenotypically discernible. In contrast, both the male and female transgenic mice coexpressing high levels of the hCG subunits (i.e., the hCG dimer) demonstrate multiple reproductive defects. The male transgenic mice have Leydig cell hyperplasia, very high levels of serum testosterone, reduced testis size, and dramatically enlarged seminal vesicles and are infertile and display overly aggressive behavior when caged with females. The female transgenic mice are also infertile, have elevated levels of serum estradiol, and progressively develop hemorrhagic and cystic ovaries with thecal layer enlargement and stromal cell proliferation and degenerating kidneys. These results suggest that the in vivo biological effects of ectopically expressed free hCGbeta subunit are distinct from those of the hCG dimer and are gender specific. These transgenic mice are useful models for studying the biology of free hCGbeta subunit, for further analyzing the gain of function effects of hCG during early Leydig cell development, and for studying the roles of hCG in ovarian and kidney pathophysiology and function.     

Reduction of testicular human chorionic gonadotropin receptors by human chorionic gonadotropin in vivo and in vitro

Changes in rat and human testicular human chorionic gonadotropin (hCG) binding sites induced by hCG were estimated in vivo and in vitro. After a single administration of hCG, the specific 125I-hCG bindings were significantly reduced for 7 and 5 days in rat and human testes, respectively. Thereafter, 125I-hCG bindings had recovered to pretreatment values by the 14th day after the administration. Occupied hCG bindings accounted for about half of the reduced bindings on the day after administration of hCG. After this time, however, the occupancy did not contribute so much to the reduction of the bindings. In experiments in vitro using the organ culture technique, an exposure to hCG for 24 h induced a dose-related significant loss of the specific 125I-hCG bindings for 7 and 5 days in rat and human testes, respectively. Thereafter, the loss was gradually recovered. These patterns of changes in 125I-hCG bindings in vitro were similar to those in vivo. These findings suggest that the reduction in hCG binding sites by hCG is due to not only occupancy but also downregulation of the binding sites and that the testicular organ culture method used in the present study is useful to study hormonal regulation of testicular function, especially in human testes.     

Effect of fetal sex on maternal and fetal human chorionic gonadotropin levels and comparison of their levels in paired umbilical arteries and veins

There were discordant results regarding the effect of fetal sex on human chorionic gonadotropin (hCG) concentrations in maternal or fetal circulation and regarding whether the levels in umbilical arteries are equal to those in umbilical veins. Totally, 188 singleton pregnancies at 36 to 42 weeks of gestation without any obstetrical or medical complication were studied. The hCG levels were measured by radioimmunoassay specific for hCG using Sb3 antibody raised against beta-subunit of hCG. The maternal ages and parities between those who gave birth to a male or a female baby were not different statistically. The birth weights between male and female babies were also not different. The serum hCG levels had a wide range in maternal circulation (200-75,200 mIU/ml) and their distribution was positively skewed. The mean value (geometric mean, G.M.) in maternal circulation for those who carried a female fetus (11,500 mIU/ml) was significantly higher than that for those carrying a male fetus (6,470 mIU/ml) (P less than 0.001, Student's t-test). The hCG concentrations in umbilical veins of female fetuses were also higher than in those of male fetuses (G.M., 26.8 vs 19.5 mIU/ml, P less than 0.01, Student's t-test). Umbilical arterial hCG levels (G.M., 10.05 mIU/ml) were statistically not different from umbilical venous levels (G.M., 10.92 mIU/ml) (paired t-test).(ABSTRACT TRUNCATED AT 250 WORDS)     

Intracellular immature subunits of human chorionic gonadotropin in first trimester placental cells: purification and characterization

As we previously reported [Sakakibara et al. (1986) Biochem. Biophys. Res. Commun. 137, 443-452; and Tominaga et al. (1989) J. Biochem. 105, 992-997], subunits of human chorionic gonadotropin (hCG) containing immature N-linked sugar chains (immature subunits), i.e., the 21 kDa form of alpha-subunit and the 23 and 19 kDa forms of beta-subunit, are present predominantly in first trimester placental cells. The molecular mass of intracellular hCG consisting of these subunits, based on gel filtration, was approximately 200 kDa, suggesting homo- or hetero-oligomerization of intracellular hCG. In the present study, we purified the 21 kDa form of alpha-subunit as well as the 23 and 19 kDa forms of beta-subunit from fresh normal first trimester placental tissues by gel filtration and reverse-phase high-performance liquid chromatography. Purified subunits were hydrolyzed (with a decrease in their molecular weighs) by endoglycosidase H and alpha-mannosidase but not by sialidase or sialidase followed by O-glycanase, indicating that those forms have presumably only high-mannose-type N-linked sugar chains but not O-linked sugar chains of the type present in mature beta-subunit. Fifteen cycles of Edman degradation of the purified forms of the subunits were performed. Only one phenylthiohydantoin amino acid, which was the same amino acid as in the urinary beta-subunit, was detected at each step for the mixture of 23 and 19 kDa forms of beta-subunit, indicating that the protein backbones of both forms are identical to each other as well as to the urinary beta-subunit.(ABSTRACT TRUNCATED AT 250 WORDS)     

The synthesis and secretion of human chorionic gonadotropin by tissue slices from first trimester placentas

Placental tissue slices from first trimester placentas synthesize and secrete proteins labeled by radioactive glucosamine are preferentially secreted as compared to proteins in general. One of the proteins synthesized and secreted is hCG. Processing and secretion of proteins, including hCG, by the tissue slices need a two-hour period. Both secretion and glycosylation of the protein can take place independently of protein synthesis. A method was developed for the specific determination of newly synthesized radioactive hCG in placental tissue.Department of Reproductive Biology, Case Western Reserve University, Cleveland, Ohio, USA     

Determination of serum unconjugated estrone, estradiol-17β and estriol during pregnancy by selected ion monitoring

A simple, rapid and highly specific method by selected ion monitoring (SIM), using 9α,11α-[²H₂]estrone, [2,4-²H₂]estradiol-17β and 2,4-[²H₂]estriol as internal standards, was developed for the determination of serum estrogens during pregnancy. Serum samples were submitted to a simple extraction procedure and were analysed after formation of the trifluoroacetic anhydride derivative. The inter-assay coefficients of variation for estrone, estradiol-17β and estriol were 3.73%, 3.42% and 3.49%, respectively. The results obtained by SIM were compared with analysis performed using radioimmunoassay.     

Diagnosis and monitoring of pregnancy in mice: correlations between maternal weight, fetal and placental mass and the maternal serum levels of progesterone, pregnancy-associated murine protein-2 and alpha-fetoprotein

Outbred Bom:NMRI mice were weighed daily for 18 days from observation of a vaginal plug. In a separate experiment, fetuses and placentae were weighed on each day of pregnancy. Pregnancy can be determined with 99% certainty on day 12 of gestation by the maternal body weight increase from day 1. The pregnancy-specific proteins alpha-fetoprotein (m-AFP) and pregnancy-associated murine protein-2 (PAMP-2), of fetal and placental origin respectively, were detectable on days 8 and 10 in the maternal circulation. Significant correlations were observed between m-AFP and fetal weight and PAMP-2 and placental weight. These markers may therefore be useful in the monitoring of fetal growth and placental growth respectively.     

Heterogeneity of human chorionic gonadotropin in various biological fluids as revealed by chromatofocusing

This study demonstrates that chromatofocusing is powerful in analyzing multiple forms of hCG from biological fluids. For analyzing hCG from biological fluids, it is necessary to perform chromatofocusing, in the range of pH 6.2-3.0 and pH 9.0-6.0. By chromatofocusing, highly purified hCG (CR121) was found to be acidic, in the range of pI 4.22-3.8, and hCG beta was more acidic, in the range of pI 4.0-3.2. Moreover, hCG from the first trimester pregnancy, hydatidiform mole or choriocarcinoma was also mainly acidic. Therefore, chromatofocusing in the range of 6.2-3.0 was suitable for analyzing purified hCG, hCG beta, and urinary hCG from the first trimester pregnancy, hydatidiform mole and choriocarcinoma. On the other hand, because hCG in the third trimester pregnancy and the toxemia of pregnancy were mainly alkaline, the chromatofocusing system in the range of pH 9.0-6.0 was suitable for analyzing hCG from the third trimester pregnancy and the toxemia of pregnancy.     

Multiple causes of pregnancy failure in hamsters precociously ovulated by human chorionic gonadotropin

Cycling adult female hamsters can be induced to mate and ovulate 24 h early by the injection of 20 IU human chorionic gonadotropin (hCG) at 1500 h on Day 3 (day before proestrus), but pregnancy is not established. Although there is evidence of decreased sperm transport in precociously ovulated females, this does not appear to be the primary cause of infertility. Reduced size and vascularity of corpora lutea (CL) in treated females suggests incomplete or failed CL activation. Control and hCG-treated females were killed by exsanguination under ether anesthesia at intervals for the first 5 days after mating. Serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin, estradiol, and progesterone were measured by radioimmunoassay. Luteinizing hormone in treated animals was very high at 2200 h on Day 1 after mating (31 h after the hCG injection), due to endogenous release, and dropped below control levels thereafter. Follicle-stimulating hormone, by contrast, was significantly lower than controls at 2200 h on Day 1 and remained low until 2200 h on Day 3 after mating. Prolactin in treated animals was not different from that in controls, except for 1000 h on Day 4, when it showed a significant dip. Estradiol in treated animals was significantly higher than in controls at 2200 h on Day 1 (when LH was also high and FSH was low), and remained high at 1000 h and 2200 h on Day 2, dropping thereafter to control levels. Progesterone was initially at control levels but had dropped significantly by 1000 h on Day 2 and remained low for the next 24 h. These results suggest that pregnancy failure is due to inadequate activation of corpora lutea. This may be due to: 1) immaturity of follicles at the time of ovulation; 2) inappropriate timing of preovulatory events; 3) the luteolytic effects of high levels of LH or estradiol or both; 4) the low level of FSH in the early stages of corpus luteum development; or 5) a combination of the above. Abnormalities of prolactin secretion were not investigated in detail but cannot be ruled out at this time.