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At least 19 recordsLinked to original sources
PubMed1982

[Determination of serum unconjugated estetrol by selected ion monitoring with application of deuterated estetrol as an internal standard].

A rapid and highly specific method for determination of serum estetrol during pregnancy and at delivery is developed using a gas chromatography-mass spectrometry with application of newly synthesized deuterated estetrol as an internal standard. Evaluation of the method assessed by recovery experiments was 102.4 and 103.0 percent when 2 and 4ng of estetrol was added to 0.5ml of male serum. The coefficient of variation were 2.54 and 2.84 percent, respectively. The results obtained by the present method are correlated well with those obtained by conventional RIA. Serum unconjugated estetrol levels during pregnancy increased with progressing gestation. The levels from the 36th to the 40th week were 749.8 +/- 281.5pg/ml (mean +/- S.D.) The levels in umbilical cord blood at delivery were also measured: Umbilical vein were 8,064.0 +/- 6,595.4pg/ml which were statistically higher than in umbilical artery (3,515.9 +/- 1,553.8pg/ml) and in maternal peripheral vein (1,209.0 +/- 530.3pg/ml).

Deuterium↗
PubMed1976

Syntheses of estetrol monoglucuronides.

Four possible monoglucuronides of estetrol (estra-1,3,5(10)-triene-3,15 alpha, 16 alpha, 17 beta-tetraol) have been prepared from appropriately protected estetrol by the Koenigs-Knorr reaction employing cadmium carbonate as a catalyst. Condensation of methyl acetobromoglucuronate with estetrol 15,16,17-triacetate provided the 3-glucuronide acetate-methyl ester in a satisfactory yield. Introduction of the glucuronyl residue into C-17 was similarly attained by the use of estetrol 3-benzoate 15,16-acetonide. When estetrol 3,17-diacetate and acetobromosugar were stirred in anhydrous toluene in the presence of cadmium salt, the reaction occurred at C-16 and C-15 yielding two isomeric monoglucuronide derivatives in a ratio of ca. 5 to 2. Removal of the protecting groups in the four glucuronide acetate-methyl esters gave the desired estetrol glucuronides, respectively. These synthetic substrates underwent readily enzymatic hydrolysis with beef-liver beta-glucuronidase to afford estetrol.

Animals↗
PubMed1984

Uterine vascular effects of estetrol in nonpregnant ewes.

Estetrol is produced by the fetal liver and has been suggested to be a sensitive indicator of fetal well-being. Although the uterine vascular effects of estrogens (17 beta-estradiol, estriol, and estrone) have been extensively investigated in our laboratory and those of others, the ability of estetrol to dilate the ovine uterine vasculature is not presently known. The present experiment was designed to compare the vasoactivity of estetrol to that of a second pregnancy-associated estrogen, estriol. Five nonpregnant oophorectomized ewes were chronically instrumented with catheters in the femoral artery, femoral vein, uterine arteries, and electromagnetic flow probes on both uterine arteries. Upon recovering from operation, animals received unilateral intra-arterial (uterine) injections of either estriol (0.1, 0.3, 1, and 3 micrograms) or estetrol (1, 3, 10, and 30 micrograms). Ewes received only one dose of either estetrol or estriol daily and all doses were given in a randomized order. Uterine blood flow responses were continuously monitored and the time of onset, peak, and duration were recorded. The time of onset (38 +/- 2 minutes), time of peak response (75 +/- 1 minute), and duration (189 +/- 7 minutes) were approximately equal to those observed for estriol. On the basis of the data obtained in the present study we have determined that estetrol is 15 to 30 times less potent than estriol as a uterine vasodilator.

Animals↗
PubMed1976

Radioimmunoassay of 15alpha-hydroxyestriol (estetrol) in pregnancy serum.

A more specific antisera against 15alpha-hydroxyestriol (estetrol) was produced in rabbits by immunization with 6-oxoestetrol-6-carboxy-methyloximino-bovine serum albumin. The synthesis of estetrol tetraacetate was greatly improved. Characterization of estetrol antisera revealed that it is more specific than those formerly obtained. A simple method of extraction of estetrol with alcohol from serum with high recovery is described. A radioimmunoassay method for pregnancy serum is characterized in regard to its specificity, accuracy, sensitivity and precision. The method is able to measure as little as 50 pg/tube or 167 pg/ml of serum. The intraassay coefficient of variation is 7.8% and that for interassay including personnel variation is 14.2%. Accuracy of the method, as determined by the recovery of non-radioactive estetrol (1 ng/ml) added to non-pregnancy serum, is found to be 89 +/- 8 (SD)%, CV = 8.7%, without correction for experimental losses. One hundred twelve pregnancy sera were analysed; the values obtained from normal subjects in the third trimester ranged from 240-950 pg/ml. The values obtained by this method are somewhat lower than those reported previously, presumably due to the higher specificity of the antibody.

Chemical Phenomena↗
PubMed1977

A radioimmunoassay of plasma unconjugated and conjugated estetrol.

A radioimmunoassay for the measurement of both unconjugated and conjugaged estetrol in plasma has been developed. The antiserum obtained after 6 months of immunization with 6-oxoestetrol-6-(O-carboxy-methyl)oxim-BSA was used at a final dilution of 1:90,000 and showed almost no cross reaction with other steroids except for estriol at 1.24%. Esterol-glucosiduronate was synthesized by incubating with adrenalectomized rat liver homogenate and uridine diphosphoglucuronic acid. Then, plasma estetrol-glucosiduronate was measured in the same manner for unconjugated estetrol after hydrolysis with beta-glucuronidase. Sephadex LH-20 column chromatography (7X110 mm, benzene:methanol, 85:15) was employed for accurate assessment. The sensitivity was 10 pg and the smallest amount measurable was 40 pg/sample. The method bland was consistently negligible. The intra and inter assay precision was 11.8% and 14.2% for unconjugated estetrol and that for estetrol-glucosiduronate was 13.5% and 17.1%.

Antibody Specificity↗
PubMed1991

Automated direct high-performance liquid chromatographic assay for estetrol, estriol, cortisone and cortisol in serum and amniotic fluid.

An automated direct assay for the simultaneous determination of unconjugated estetrol, estriol, cortisone and cortisol in serum and amniotic fluid, using high-performance liquid chromatography with electrochemical detection and ultraviolet detection, has been developed. The analysis time is ca. 1 h. This system offers good reproducibility with low coefficients of variation (estetrol, 2.3%; estriol, 2.3%; cortisone, 2.6%; cortisol, 1.9%). Detection limits are low enough for routine determinations (estetrol and estriol, 150 pg; cortisone and cortisol, 5 ng). Comparison of the values measured by the present method and by radioimmunoassay revealed significant correlations for estetrol (r = 0.787, p less than 0.01), estriol (r = 0.957, p less than 0.01), cortisone (r = 0.956, p less than 0.01) and cortisol (r = 0.865, p less than 0.01). This system proved to be valuable in monitoring feto-placental function.

Amniotic Fluid↗
PubMed1985

Daily variation of serum unconjugated estriol and estetrol in normal pregnancy.

Serum unconjugated estriol and estetrol were assayed daily in seven nondiabetic, uncomplicated third-trimester pregnancies to define the daily variation of these compounds. When compared to the mean of the three preceding days' values, or to the highest mean of three consecutive daily values previously obtained in a pregnancy, daily estriol and estetrol values fell greater than or equal to 40% on 1.2 and 0% of occasions, respectively. Isolated estriol values represented falls of greater than or equal to 40% from previously obtained single estriol values on 2% of occasions, and no isolated estetrol values fell greater than or equal to 40% from any other isolated values obtained in a given pregnancy. These results define the stability of daily serum estriol and estetrol in late-gestation normal pregnancy, although they emphasize the large variability encountered when comparing isolated estriol values.

Circadian Rhythm↗
PubMed1981

[The determination of unconjugated estrone, estradiol, estriol and estetrol in serum or amniotic fluid by high performance liquid chromatography with an amperometric detector (author's transl)].

A simultaneous microdetermination of unconjugated estrone, estradiol, estriol and estetrol in serum or amniotic fluid by High Performance Liquid Chromatography with an Amperometric Detector is described. Steroids in serum or amniotic fluid were extracted with 10 volumes of ethyl ether, and then ether extract was evaporated to dryness under N2 gas. After defatting with a mixture of 50% methanol/n-hexane, the methanol phase was evaporated to dryness under N2 gas. The residue was applied to microcolumn packed with 2 ml volume of Sephadex LH-20 in the eluting solvent benzene/methanol (85:15). Fractions contained estrone and estradiol; estriol and estetrol were collected and then evaporated to dryness under N2 gas. The sample solution was applied to HPLC using a reverse phase ODS column and acetonitrile: 0.1M KH2 PO4 47:53 for estrone and estradiol fraction, and 30:70 for estriol and estetrol fraction as a mobile phase, respectively. The fraction of each estrogen was separated completely within a 20 minute period. The limit of detection of estrone, estradiol, estriol and estetrol was 50 pg, respectively.

Amniotic Fluid↗
PubMed1985

15- and 16-hydroxylations of androgens and estrogens in the human fetal liver: a critical step in estetrol biosynthesis.

To elucidate the main metabolic pathways which lead to the foeto-placental biosynthesis of estetrol (I), we investigated the 15 alpha- and 16 alpha-hydroxylations of potential precursors of this estrogen in the human fetal liver. We determined the 15 alpha- and 16 alpha-hydroxylation capacity of the fetal liver for each precursor by GC-MS. The results suggest that estetrol is derived only from estradiol sulfate (II) and DHEA sulfate (III). 15 alpha-Hydroxy-androstenedione (IV) can no longer be regarded as a good precursor of estetrol. The phenolic pathway appears to be a more likely route than the neutral pathway, even when derived from DHEA sulfate.

Androgens↗
PubMed1975

Plasma estetrol as an index of fetal well-being.

Estetrol (15alpha-hydroxyestriol or E4) is considered to be a specific product of fetal liver and has been suggested as a good indicator of fetal well-being. The concentration of unconjugated estetrol (E4) was measured by rapid and specific radioimmunoassay in 1 ml of maternal plasma. E4 levels prior to the 18th week of pregnancy were often undetectable (smaller than 50 pg/ml). The mean plasma E4 level at term of 1.2 ng/ml was 7-fold higher than that observed at 24 weeks of gestation, and no diurnal variations were found. E4 levels in fetal plasma at term were 12-fold higher than those in maternal plasma and no fetal arterial venous differences were found. Umbilical vein but not maternal plasma levels of patients undergoing vaginal delivery were higher than those undergoing cesarean section (P smaller than 0.05) suggesting increased adrenal output of E4 precursors during labor. In patients with severe Rh-isoimmune disease plasma E4 levels were not helpful in assessing fetal well-being. However, in patients with chronic hypertension or pre-eclampsia, subnormal plasma E4 concentrations always preceded intrauterine fetal death. Plasma E4 appears to be a good indicator of fetal well-being in patients with hypertensive disease of pregnancy.

Amniotic Fluid↗
PubMed1975

[Excretion of estriol, estetrol, 16-epi-estriol, 16-keto-estradiol and 16-hydroxyestrone in the 24-hour urine of pregnant women in the last trimester].

In this publication a method is given which allows simultaneous estimation of estriol, estetrol, 16-epiestriol, 16-ketoestradiol and 16-hydroxyestrone in urine of pregnant women. First conjugates are precipitated with ammoniumsulfate and hydrolyzed. Then the steroids are extracted and converted to azodyes by reacting with the diazonium salt dark blue r. After separation by thin layer chromatography the azodyes are measured by remission analysis with a chromatogramm spectrophotometer. From the data obtained from 66 cases norm groups were set up for the excretion of the steroids in the 3rd trimester of pregnancy. In the last month of pregnancy the average excretion, expressed in % of excreted estriol, is as follows: estetrol 5,7%, 16-epiestriol 3,1%, 16-ketoestradiol 7,0%, 16-hydroxyestrone 5,3%.

Adult↗
PubMed1978

Precursor role of 15alpha-hydroxyestradiol and 15alpha-hydroxyandrostenedione in the formation of estetrol.

Studies were designed to elucidate the origin of estetrol (15alpha-hydroxyestriol (estra-1,3,5(10)triene-3,15alpha,17beta-tetrol) or E4) during late human pregnancy. 3H-Labelled 15alpha-hydroxyestradiol (3,15alpha-dihydroxyestra-1,3,5(10)-trien-17-one or 15E2) and 14C-labelled 17beta-estradiol (estra-1,3,5(10)-triene-3,17beta-diol or E2) were infused into the fetus during transfusion in utero for erythroblastosis fetalis, and in another study the same substrates were injected intravenously into the maternal circulation. In a third study, 3H-labelled 15alpha-hydroxyandrostenedion (15alpha-hydroxyandrost-4-ene-3,17-dione or 15delta4) and 14C-labelled E2 were infused into the fetus. Maternal urine was collected for 5--6 days, and after Glusulase hydrolysis, the following metabolites were isolated: estriol (estra-1,3,5(10)-triene-3,16alpha,17beta-triol or E3) containing 14C only and 15alpha-hydroxyestrone (3,15alpha-dihydroxyestra-1,3,5(10)-trien-17-one or 15E1), 15E2, and E4, all containing both labels. From the isotope content of these metabolites, it was concluded that E4 was derived from both fetal E2 and 15delta4 and only partially via 15E2. When administered to the fetus E2 and 15delta4 contributed approximately equal amounts to urinary E4. The yield of 15alpha-hydroxylated estrogens from E2 injected into the mother was very low indicating the predominantly fetal origin of the 15alpha-hydroxylase. 15delta4 was a better precursor than E2 for urinary 15E2.

Androstenedione↗
PubMed1979

Radioimmunoassay of unconjugated and total serum estetrol using a 125I-iodinated tracer.

A radioimmunossay (RIA) for the measurement of both unconjugated and total serum estetrol has been developed, using an antiserum to an E4-3-conjugate and a 125I-radioiodinated E4 tracer. Assay of dried ethyl ether extracts was used for the determination of unconjugated E4, while a direct measurement of unextracted hydrolyzed serum in the presence of 0.3% 8-anilino-1-naphthalene sulphonic acid (ANS) proved adequate for total E4. Assay reliability was evaluated and the procedure standardized through a series of tests aimed at assessing accuracy, sensitivity and precision. No steroidal interference was found to practically affect the assay (0.3% estriol cross-reactivity), nor were solvent and sample blanks observed in the case of unconjugated E4. For total E4 assay, the sample blank effects were acceptably overcome by using hydrolyzed male serum and 0.3% ANS, as a standard diluent. An interassay variability amounting to approximately 10 and 6% resulted for unconjugated E4 and total E4 RIA, respectively. A number of serum samples (285 for unconjugated E4, 147 for total E4) randomly collected throughout normal pregnancy were assayed. The unconjugated E4 levels at 15th week and at term were 62.7 +/- 22.6 and 766.5 +/- 208.2 (SD) pg/ml, respectively. Total E4 was about 6--7 times higher than the levels of free E4 and increased 7 times from the 15th week to term.

Circadian Rhythm↗
PubMed1985

Rapid and simultaneous measurement of estrone, estradiol, estriol and estetrol in serum by high performance liquid chromatography with electrochemical detection.

A high performance liquid chromatographic (HPLC) method with electrochemical detection (ECD) was developed for the simultaneous measurement of estrone, estradiol, estriol and estetrol in serum. These hormones were extracted with diethylether, chromatographed on an silica-octadecyl silane (ODS) column with an eluent of phosphate buffer solution-acetonitrile-methanol (volume ratio 152:85:40), and detected by ECD at +1.0V vs. Ag/AgCl. In comparisons between the values measured by this method and radioimmunoassay, significant correlations were noted for estrone (r = 0.759, p less than 0.01), estradiol (r = 0.816, p less than 0.001) and estriol (r = 0.830, p less than 0.001). In clinical applications of this method, differences between cases of the normal and the anencephalic pregnancy in the thirty-eighth week of gestation were distinct not only in the individual estrogen, but also in the profile analysis of estrogens. With this method, all 4 serum estrogens above approximately 500 pg/ml could be measured within 2 h, and the method seemed to be clinically applicable.

Chromatography, High Pressure Liquid↗
PubMed1979

Estradiol and estetrol plasma levels before and after intravenous administration of dehydroepiandrosterone sulfate in normal and pathologic pregnancies.

Intravenous injections of 50 mg dehydroepiandrosterone sulfate (DHEAS) were given to 7 women with normal pregnancies and 5 with pathologic pregnancies and the serum levels of 17 beta-estradiol and estetrol were assayed before and at 15 or 30-minute intervals for three hours after the injection. All tests were carried out during the 25th to 36th week of amenorrhea. Serum estradiol rose rapidly in normal subjects and remained high to the end of the test. In patients with gestational pathology the estradiol pattern was not significantly different from that of the controls. Esterol plasma levels showed a biphasic pattern with an initial rise at 30 min. and a second rise at 90 min. in normal pregnancies, whereas in pathologic pregnancies this response was either lacking completely or was markedly reduced compared to the controls.

Dehydroepiandrosterone↗
PubMed1979

Plasma levels of unconjugated estetrol and estriol and of total estriol in normal human pregnancy.

The course of normal pregnancy in 54 patients was monitored by weekly assays of Unconjugated Estriol (E3U), Total Estriol (E3T) and Unconjugated Estetrol (E4U). These subjects were divided into two groups: one of those patients who delivered a fetus with a weight above the 50th percentile and the other of those who delivered a fetus with a weight below the 50th percentile. No significant difference was found between these two groups and it is not therefore possible to have information regarding the weight of the fetus, starting from the weekly values of these hormones. Analogous variations of the three hormones were found as pregnancy progresses. However, the rate of increase for E4U was higher than for E3T and E3U.

Adolescent↗
PubMed1982

Estetrol and utero-placental flow after progesterone load.

On the basis of recent demonstration in animals of the effect of some hormones on uteroplacental flow, the Authors examined the response of plasmatic Estetrol (15 alpha-hydroxy-estriol) after the administration of progesterone to pregnant women with low Estrogen values. The increase of this compound was related to an improvement of placental function, probably dependent on an increase of available O2, and therefore on uterine blood flow. This can justify a progesterone treatment in such pregnancies.

Estetrol↗
PubMed1982

Unconjugated estetrol in normal pregnancy.

The Authors studied the levels of Estetrol (15 alpha-hydroxyestriol) in the amniotic fluid, in maternal and foetal plasma, by the RIA method, in near-term pregnancies. Higher concentrations of this steroid were found in the foetal plasma and in amniotic fluid than in the maternal plasma. These data, even though of little clinical importance, confirm the foetal origin of this compound and suggest further studies, especially in the amniotic compartment.

Amniotic Fluid↗