Total Estriol Research Articles

The prognostic and diagnostic value of total estriol in urine and in serum and of human placental lactogen hormone in serum in the last part of pregnancy

The benefit to the antenatal care from using estriol and human placental lactogen (hPL) determinations is emphasized and likewise that special attention must be paid to values below the reference intervals. Referring to biosynthesis and place of production, a survey is given of the various causes of low estriol and/or low hPL values, and a number of clinical cases illustrate the matter. A follow-up study of children from pregnancies with low estriol values has disclosed an alarming number of cases of severe handicaps.

PLASMA LEVELS OF OESTRIOL‐17β OESTRIOL AND HUMAN PLACENTAL LACTOGEN DURING BED REST

Plasma unconjugated oestradiol-17 beta, total oestriol and human placental lactogen levels were measured in twelve healthy volunteers admitted for bed rest in the last trimester of pregnancy. No significant alteration in levels was observed.

Renal clearances of estriol conjugates in normal human pregnancy at term

In late human pregnancy more than 90 per cent of the total estriol (E3) in body fluids consists of four conjugates, estriol-3-sulfate (E3-3S), estriol-16-glucosiduronate (E3-16G), estriol-3-glucuronide (E3-3G), and estriol-3-sulfate-16-glucosiduronate (E3-3S-16G). Since the relative amounts of E3 in blood and urine would be determined by the kidney, the renal clearance of each conjugate was determined and compared with inulin and p-aminohippuric acid (PAH) clearance, as measures of glomerular filtration rate (GFR) and the effective renal plasma flow. Five women were studied in the lateral decubitus position with inulin and PAH infusion. Samples of blood and urine were collected at 40 minute intervals and analyzed. The method for E3 conjugates involved separation of the four conjugates on Sephadex LH-20, enzyme hydrolysis, and radioimmunoassay. Renal clearances for E3-3S and E3-3S-16G were below inulin. E3-3G approximated inulin; E3-16G exceeded inulin and approached PAH. In plasma E3-3S-16G represented 48.4 ± 7.2 per cent; in urine E3-16G represented 69.5 ± 7.3 per cent of total E3. Thus, different conjugates predominate in blood and urine.

A simple radioimmunological method for the determination of plasma total oestriol during pregnancy

A simple method for the determination of total oestriol in the plasma from late-term pregnant subjects using a specific radioimmunoassay is described. Over 30 samples can be evaluated within the working day and details of precision, accuracy, specificity and sensitivity are reported. A normal range with 120 samples from week 30 to term has been established.

Estriol in pregnancy: IV. Normal concentrations, diurnal and/or episodic variations, and day-to-day changes of unconjugated and total estriol in late pregnancy plasma

Normal values of unconjugated, total, and immunoreactive (measured without extraction) plasma estriol (E3) have been determined from radioimmunoassay data obtained in 217 uncomplicated third-trimester pregnancies. Small but significant diurnal variations in unconjugated and total plasma E3 have been observed in a study comprising 12 women who were hospitalized during late pregnancy for diabetes, toxemia, or placenta previa. The late morning decreases in unconjugated and the afternoon/evening decreases in total plasma E3 concentrations, averaging some 10 to 15 per cent, were overshadowed by considerable episodic fluctuations and may thus be clinically irrelevant. Day-to-day changes of unconjugated and total plasma E3 concentrations in late pregnancy were similar and smaller than changes in urinary E3 measurements. The urinary E3/creatinine ratio, however, reducing inadequacies of 24 hour urine collections, varied less than unconjugated or total plasma E3. The data suggest that a decrease in unconjugated or total plasma E3 must exceed 40 to 45 per cent of the mean of the three preceding determinations if it is to be considered a signal of fetal distress.

16-Sulfates of estriol in body fluids of human pregnancy at term

A method was developed for the assay of estriol-16-sulfate (E 3-16s) and estriol-3, 16-disulfate (E 3-3, 16-diS) in maternal serum, cord serum and amniotic fluid at delivery in human pregnancy, Tritiated E 3-16S and E 3-3, 16-diS are added to the fluid being analyzed. The conjugates are separated and purified by sequential chromatography on alumina, Celite and Sephadex LH-20. Each conjugate is hydrolyzed with Glusulase and the released estriol is quantified by radioimmunoassay. E 3-3, 16-diS was found in each fluid, most concentrated in the cord serum. Small amounts of E 3-16S were found in some amniotic fluids, and this conjugate was virtually absent from the sera. These new estriol conjugates comprise less than 1 percent of total estriol, apparently too low to be of diagnostic value in human pregnancy.

Plasma Oestriol Levels in Normal Pregnancy

Summary: Plasma total oestriol levels have been measured in a prospective study of 105 women in normal pregnancy, using a fluorimetric assay. There is seen to be good correlation between all recently published studies of normal levels, obtained by several different methods. The statistically significant rise which occurs in each 4‐week period between 24 and 40 weeks of gestation offers a new approach to the screening of obstetric patients for unexpected failure of fetal–placental function.

Radioimmunoassay for estrogens in maternal blood in late pregnancy: Values for normal and complicated pregnancy

A previously described radioimmunoassay which measures free estrogens and estriol-16-glucuronide but not 3-sulfoconjugated estrogens was applied to maternal plasma in normal and complicated pregnancy. The results were compared to those reported in the literature for total estriol. The concentration of immunoreactive estriol, i.e., the estrogens measured by this assay, increases with gestational age more rapidly than total estriol. Following delivery, the clearance of immunoreactive estriol is faster than that of total estriol. The concentration of immunoreactive estriol in blood declined in some cases of complicated pregnancy and was undetectable in women with a hydatidiform mole, an anencephalic fetus, and a dead fetus.

An assessment of “free” and conjugated estriol in uncomplicated and complicated pregnancy plasma

Determination of “free” and conjugated estriol was performed on serial plasma samples from 15 normal pregnancies and an equal number of those complicated with pre-eclampsia and/or hypertension. In both categories, the levels of circulating “free” estriol did not show an appreciable increase with progressing gestation but remained within a range of 1.2 to 5.5 μg per 100 ml. of plasma. “Free” estriol accounted for approximately 14 per cent of total estriol in the third trimester of pregnancy. One patient showed a dramatic increase in total estriol with the development of severe pre-eclampsia; however, the levels of “free” estriol remained virtually unchanged. A similar observation was made in one patient with hypertensive vascular disease. No increase in the proportion of the “free” estriol over the conjugated form was observed in pregnancies with impaired renal function. The over-all pattern of “free” and conjugated estriol in normal and toxemic pregnancies appears to be essentially the same.

Estriol in plasma: A compartmental study

A radioimmunoassay technique has been used to measure unconjugated estriol, estriol sulfate, and estriol glucosiduronate. The distribution of these compounds in plasma, blood cells, and interstitial fluid has been studied. It was found that in the plasma roughly two thirds of each constituent was bound to protein. All three forms also occur in the interstitial fluid but in much lower concentration. The proportion of estriol in interstitial fluid not bound to protein was found to be larger than in plasma. Plasma volumes were measured and it was calculated that the total estriol contained in the interstitial fluid was somewhat more than in plasma. Small amounts of each form of the steroid were associated with the cellular elements in blood, the proportions being larger in the case of unconjugated estriol and estriol sulfate than with estriol glucosiduronate.

Circadian rhythms of serum and urinary estrogens in pregnancy.

Diurnal variations in serum unconjugated estradiol-17β (SE2), serum total estriol (SE3), total urinary estrogens (UE), and UE/creatinine ratios (E/C) were determined on samples obtained at 4-hr intervals from 22 women in the third trimester of normal pregnancy. Analysis of variance indicated significant variations in SE2 (p < 0.001), UE (p < 0.01), and E/C (p < 0.05). Multiple comparison of means showed maximum values at 12 pm to be significantly greater than minimum values at 12 am (p < 0.01). The SE3 rhythm was less marked with individual daytime (8 am–12 pm–4 pm) means significantly greater (p < 0.001) than those at nighttime (8 pm–12 am–4 am). It is proposed that this rhythm reflects changes in availability of estrogen precursors known to be secreted rhythmically by the maternal adrenal.

Concentrations of human chorionic gonadotropin, progesterone, and unconjugated and total estriol in umbilical artery and vein plasma at term

Umbilical arterial and venous blood samples were obtained at term, and analyzed for human chorionic gonadotropin, progesterone, and unconjugated and total estriol. Levels of these hormones in arterial plasma were 1,577 ± 209, 378 ± 54, 30.5 ± 9, and 1,389 ± 115 ng. per milliliter (± standard error of the mean), respectively. The corresponding levels in venous plasma were 1,285 ± 188, 677 ± 94, 95 ± 19, and 1,302 ± 111 ng. per milliliter, respectively. These results confirm that the placenta produces progesterone and hydrolyzes estriol conjugates, and the fetus actively conjugates estriol and metabolizes progesterone arriving from the placenta. Higher levels of human chorionic gonadotropin were associated with female fetuses (P < 0.0.5). Umbilical arterial and venous blood samples were obtained at term, and analyzed for human chorionic gonadotropin, progesterone, and unconjugated and total estriol. Levels of these hormones in arterial plasma were 1,577 ± 209, 378 ± 54, 30.5 ± 9, and 1,389 ± 115 ng. per milliliter (± standard error of the mean), respectively. The corresponding levels in venous plasma were 1,285 ± 188, 677 ± 94, 95 ± 19, and 1,302 ± 111 ng. per milliliter, respectively. These results confirm that the placenta produces progesterone and hydrolyzes estriol conjugates, and the fetus actively conjugates estriol and metabolizes progesterone arriving from the placenta. Higher levels of human chorionic gonadotropin were associated with female fetuses (P < 0.0.5).

A Versatile Radioimmunoassay for the Determination of Serum Oestriol in Pregnancy

A versatile radioimmunoassay for serum oestriol in pregnancy has been developed which requires 10 μ| of serum (for total) or 50 μ| (for unconjugated). Selection of the optimum conditions for the hydrolysis of serum oestriol conjugates, the isolation of free oestriol, the displacement of tritiated oestriol by cold oestriol and the separation of the free and bound fractions is described. Total oestriol levels doubled between weeks 34 and 38 of normal pregnancy, very little change occurring in the mean level after the 38th week of gestation. In a random series of pregnancy sera there was a significant correlation between total and unconjugated oestriol.

Steroid hormone levels in human fetal blood during delivery

Fetal blood samplings were made during labor according to Saling and Schneider's13 techniques, and microdeterminations of plasma total estriol, dehydroepiandrosterone, and 16α-hydroxy-dehydroepiandrosterone were performed. All the steroids showed a tendency to increase during labor, and the difference in estriol levels was significant. The possible significance of the increase in estriol level and the fetal adrenal function during labor is discussed.

Gas-Chromatographic Determination of Total Estriol in Amniotic Fluid

Abstract A simple gas-chromatographic procedure is described for determination of total estriol in amniotic fluid. Before 20 weeks gestation the concentrations (&amp;lt;1 µg/100 ml) were not meaningful. After 20 weeks there was a gradual rise, followed by a rapid rise during the last weeks of pregnancy.

ESTRIOL SECRETION BY THE HUMAN TERM PLACENTA.

“Free” (solvent-extractable) and “conjugated” (acid-hydrolyzable) estriol levels and their sum as total estriol were determined in paired samples of intervillous space and maternal arm vein plasma and in paired samples of umbilical artery and vein plasma. Estriol levels were determined by the method of Roy and Brown. Free and total estriol levels in the intervillous space plasma were significantly higher than those found in the maternal arm vein plasma. This suggests the transfer of estriol from the placenta to the mother and might alone account for the high urinary estriol levels found in pregnancy. No differences between free, conjugated or total estriol values were found in paired umbilical artery and vein plasma samples.