Pregnancy Estrogen Research Articles

Receptivity, proceptivity and attractivity of pregnant and pseudopregnant rats

In the present study the effects of pregnancy and of pseudopregnancy on oestrogen-induced receptivity, proceptivity and attractivity in female rats were investigated. Receptivity and proceptivity were determined in heterosexual pair tests. Attractivity was determined using a new method: a residential plus-maze. It was found that during the second half of pregnancy oestrogen treatment did not induce the above-mentioned behaviours. However, during the second half of pseudopregnancy oestrogen treatment resulted in high levels of these behaviours. Also, combined oestrogen plus progesterone treatment showed similar high frequencies of these behaviours in pseudopregnant rats.

Luteotropic role of estrogen in early pregnancy in the rat.

The role of estrogen and PRL in luteal cell function in early pregnancy (between days 6–8) was examined. On day 6 post coitum, rats were injected sc with LH antiserum or were hypophysectomized and hysterectomized and treated with PRL (250 or 500 μg/day), estradiol (100 μg/day), PRL and estradiol together, or the appropriate vehicle. Within 48 h after injection of LH antiserum, intraluteal concentrations of estradiol decreased to 1.1 ± 0.2 pg/mg (compared to 3.3 ± 0.3 pg/mg in control animals treated with normal horse serum), while serum progesterone decreased by only 22%. The rats remained pregnant. Within 24 h after hypophysectomy-hysterectomy, serum progesterone was 43 ± 9 ng/ml and the total luteal content of estradiol receptor (cytosolic plus nuclear) decreased by 75% compared with control sham-operated animals. Treatment with estradiol alone (100 μg/day) further decreased serum progesterone and the concentration of estradiol receptor in the corpora lutea. PRL partially maintained progesterone secreti...

Some kinetic properties of human placental estradiol-17β dehydrogenase: Patterns of inhibition by adenine nucleotides

Estradiol dehydrogenase from human placenta catalyzes the reversible interconversion of estradiol-17β and estrone. In the placenta, it is believed to catalyze the irreversible reduction of 16α-hydroxyestrone to estriol, the major estrogen in human pregnancy. It can function with either NAD + or NADP + as hydrogen acceptor. The NAD(H)-linked activity of the enzyme is markedly inhibited by 0.5 m m 2′-AMP, and there are no detectable effects of the same concentration of 3′-AMP, 5′-AMP and 3′,5′-cyclic AMP. However, 5′-ATP is a far better inhibitor than any of the other 5′-phosphates of adenosine, such as 5′-AMP, 5′-ADP and 5′-ADPR. Also, the enzyme activity was strongly inhibited by 2′,5′-ADP, but not by 3′,5′-ADP. On the other hand, no inhibitory effects of the nucleotides at a concentration of 0.5 m m on the NADP +-linked activity were observed. The K m values for NADP(H) are much smaller than those of NAD(H). The inhibition of estradiol dehydrogenase by 2′-AMP, 2′,5′-ADP, 5′-ATP, 5′-ADP, 5′-ADPR and 3′,5′-ADP appeared to be competitive with respect to NAD(H) or NADP(H) and non-competitive with respect to steroid. The apparent inhibitor constant (K i) for 2′-AMP calculated from Lineweaver-Burk plots was 4 μ m. This inhibitor constant is about one-tenth that of the Michaelis constant for NAD + and NADH. Lineweaver-Burk plots were made at several concentrations of 2′-AMP and the slopes plotted against 2′-AMP concentration. The replot was parabolic, indicating more than one binding site for the nucleotide. Similar results were obtained with 5′-ATP, though higher concentrations were required to achieve inhibition than in the case of 2′-AMP. The 2′,5′-ADP is an inhibitor competitive with NAD(H) though not as potent as 2′-AMP. The results clearly suggest the positive contribution of the 2′-phosphate group of the adenosine moiety of NADP + for binding the cofactor. Nicotinamide mononucleotide does not inhibit the NAD(H)- and NADP(H)-linked activities of estradiol dehydrogenase. The failure of NMN to compete with NAD(H) for the cofactor binding site seems to exclude a major role for this portion of the coenzyme in binding to the dehydrogenase; the 2′,5′-ADP moiety of the cofactor is more important for binding than the NMN group. NMN had no effect upon the inhibition by 2′,5′-ADP. These results indicate a possible role of adenosine nucleotides in regulating the activity of estradiol dehydrogenase.

Hormonal Steroid Contraceptives

The past 5-year period has served to confirm that hormonal steroid contraception carries a significant degree of morbidity and a small but by no means negligible mortality. Thromboembolism remains the major hazard and prospective as well as further retrospective studies corroborate the evidence previously available. Association with stroke and with myocardial infarction seems to have been established and where other risk factors for either exist, such as smoking, hyperlipidaemia or hypertension, it would seem wise for other contraceptive measures to be used. Individual examples of occlusive episodes in other vascular beds continue to be reported. The rate of occurrence of thrombotic complications in older women requires justification by strong social, personal or other special reasons. The pathogenesis of the vascular lesions occurring in association with oral contraceptives may have been clarified. An enhanced coagulability seems likely but an associated impairment of fibrinolytic activity may contribute to produce clinically relevant thromboembolism. The oestrogenicity of an oral contraceptive seems to determine its propensity to induce thromboembolic disease and this may be substantially or even preponderantly contributed to by the progestagen component. Occlusive lesions involving intimal proliferation have been demonstrated in a wide variety of vascular beds and suggest that female reproductive steroids may promote an intrinsic vascular lesion. Hypertension develops more frequently in women on oral contraceptives than in an otherwise comparable group who are not taking them, and although generally of a modest degree, may at times be of disastrous severity. Evidence has been forthcoming of increased activity of both adrenergic and angiotensin mechanisms, as also has increased cardiac output and blood volume. An increase in triglycerides may at times reach massive proportions and be accompanied by pancreatitis. A predilection for development of hyperlipidaemia by patients with types IV or V lipoprotein patterns may contraindicate use of combined oral contraceptives in such women. Impairment of glucose tolerance appears early amongst women on combination contraceptives and bears resemblances to ‘steroid diabetes’. The increase in total plasma cortisol is not accounted for entirely by the bound fraction; unbound cortisol also being elevated. Hepatic dysfunction consequent upon impairment of metabolic conjugation processes by sex steroids may interfere with elimination of endogenous and exogenous substances requiring conjugation. An enhanced liability to gallstone formation has been observed in both prospective and retrospective studies. What were hitherto excessively rare benign hepatic tumours, have now been described in quite substantial numbers. The pathological categorisation has been clarified but associated profuse vascularity carries a risk of rupture with exsanguinating haemorrhage. A small number of such tumours have shown malignant degeneration. The tumours may at times be multiple. A possible aetiological association with steroid induced hyperplasia of intracellular organelles is suggested. The possibility that oral contraceptives may be associated with other types of neoplasia remains under close scrutiny. A positive association of sequential oral contraceptives and adenocarcinoma of the endometrium has been suggested. However, a negative association of oral contraceptives with breast cancer incidence seems to suggest some sort of protective effect. Vaginal carcinoma in girls whose mothers had been treated with non-steroidal oestrogens in pregnancy has constituted a disconcerting reminder of the remote sequelae which may follow hormonal manipulation. Hormonal contraceptives may be responsible for induction of symptomatic hepatic porphyria or elicitation of symptoms of an underlying porphyria variegata or intermittent porphyria. A possible association with fetal malformation has come under scrutiny as a result of a consistent grouping of certain malformations in infants having had intrauterine exposure during the vulnerable period of embryogenesis. In the light of the data now available it has become increasingly necessary for oral contraceptive therapy to be under regular and well informed medical supervision. Renunciation of immediate medical responsibility for the health of women for whom they are prescribed would be entirely irresponsible.

A semi-automated fluorometric method for total estrogens in pregnancy urine.

We report a continuous-flow fluorometric method for total urinary estrogens that involves the Kober reaction, with extraction of the reaction product into dichloroethane containing trichloroacetic acid as described by Hahnel and Jones [Clin. Chim. Acta 16, 185 (1967)]. The dichloroethane extraction gives greater stability to the Kober color and sharper separation of aqueous and organic phases. The analytical system is adjusted to give maximum response to estriol 16alpha,beta-D-glucuronide, the principal estrogen conjugate in urine from late pregnancy, when calibrated with estriol standards. An initial 20-fold dilution of the sample with water increased analytical recovery of estriol conjugates from urine while maintaining adequate fluorescent response. Glucose interference was reduced by dilution and eliminated by treatment with sodium borohydride. Urinary protein up to 20 g/liter did not interfere. Total estriol, as determined by gas-liquid chromatography, comprises about 70% of total urinary estrogens in late pregnancy as measured by our continuous-flow fluorometric method. A reference range is presented based on 209 randomly collected urine specimens in which total urinary estrogens are expressed as a ratio to creatinine.

Effect of ampicillin administration on plasma conjugated and unconjugated estrogen and progesterone levels in pregnancy

The administration of ampicillin to three women in the last trimester of pregnancy caused a transient reduction in the plasma concentration of total conjugated estriol and of estriol-16α-glucuronide, as measured by a specific radioimmunoassay. Similar changes were seen in plasma conjugated estrone and estradiol levels, but the effect seemed to be more prolonged. In most cases, the reduction in plasma conjugated estrogens was greatest on the second and third day of ampicillin administration, the pattern being similar to that described previously for urinary estriol and other estrogens. There were no obvious differences in the ampicillin effect between the morning and afternoon plasma levels. Ampicillin caused no consistent change in the plasma levels of unconjugated estrone, estradiol, and estriol or in plasma progesterone. These results are discussed with consideration of our present understanding of the effect of ampicillin on the intestinal metabolism and enterohepatic circulation of steroids.

Pregnancy duration and fetal number: Effects on maternal behavior in rats

It was shown previously that in rats postpartum mothers are much more likely than pup sensitized virgin mothers to retrieve pups from a T-maze extension of their home cage. In the present experiment, the physiological basis of this difference was explored further by inducing maternal behavior (retrieving, crouching, licking) following hysterectomy-ovariectomy on Days 21, 16, and 10 of pregnancy. In general, the longer the duration of pregnancy, the shorter the latency to become maternal and the greater the propensity to retrieve pups from the T-maze. An additional group of Day 16 pregnancy terminated rats carrying six or fewer fetuses were not impaired with respect to onset of maternal behavior compared to their large-litter counterparts, but only a small percentage of these females retrieved in the T-maze. These findings suggest that both the late pregnancy estrogen surge and progesterone withdrawal after its peak and sustained secretion enhance maternal responsiveness and that T-maze pup retrieval (but not onset latency) may be additionally affected by the level of placental hormones.

Maternal serum hyaluronidase activity in pregnancy.

An unselected series of 291 pregnant women was followed during pregnancy. Maternal serum was assayed for both hyaluraonidase activity and HPL. Urine was assayed for 24 h oestrogen output. A retrospective examination of the results showed that hyaluronidase activity did not provide as good an indication of fetoplacental well-being as did either HPL or pregnancy oestrogen. There were differences, however, in the mean levels obtained in complicated pregnancy, compared to the levels in normal pregnancy. Fetal death was associated with increased hyaluronidase activity whereas fetoplacental dysfunction was associated with lower levels of hyaluronidase activity.

Estrogen, progesterone, prolactin and other changes associated with bovine lactation induced with estradiol-17beta and progesterone.

Estrogen progesterone prolactin and other changes associated with bovine lactation induced with estradiol-17beta and progesterone were investigated. Lactation was induced in 3 cows and 5 heifers with 14 sc injections of estradiol and progesterone. 2 animals also received 10 im injections of estradiol and progesterone. Injections were at 12-hour intervals and each dose contained .05 mg estradiol and .125 mg progesterone/kg body weight. Lactation was induced in all animals but postinduction increases in milk yields were subnormal and lactation yields of 4% fat-corrected milk were 50-59% of expectancy. Milk yield of all animals reached 2.5 kg/day 9-13 days after the last injection. Progesterone and total free estrogen in milk decreased markedly by 4-14 days after 1st milking or a maximum of 18 days after the last injection. Each milk hormone correlated with its plasma concentration and milk and plasma estrogen correlated with urinary estrogen excretion rate. Milk and plasma progesterone never exceeded concentrations of untreated cows during pregnancy and milk estrogen was similar after Day 2 of lactation. Plasma and urinary estrogen during treatment equaled or exceeded that of late pregnancy. Progesterone and estrogen decreased the 1st 3 days after treatment and were low when plasma prolactin increased 4-5 days later. Treatment for 7-12 days produced hormone profiles similar to those 3-7 days before parturition. When lactation was initiated plasma estrogen and prolactin were lower than data reported for parturient lactogenesis.

Some ionic and dilution effects in the measurement of urinary oestrogens in pregnancy.

The estimation of oestrogen in aqueous solutions and pregnancy urines using an automated procedure is affected by the presence of certain ions, and by dilution. These effects have been studied by calculating regression equations from the values obtained with urines to which ions have been added with and without urine dilution. The results suggest that the ionic effect is chemical rather than physical and that there is no advantage in including a predilution step in the analysis. Other means of removing the ionic effects have so far proved unsuccessful.

PLASMA LEVELS OF ESTRONE SULFATE, ESTRONE AND ESTRADIOL-17β IN THE COW AROUND PARTURITION

Estrone sulfate, estrone, and estradiol-17β have been assayed in blood plasma taken from the mammary vein of five pregnant cows before and after parturition. While there were considerable individual variations, the mean plasma levels of estrone sulfate (13.4 ng/ml), estrone (1 ng/ml) and estradiol-17β (1 ng/ml) remained fairly constant over the period of blood collection prior to parturition (−88 h to −2 h). The levels of all three estrogens dropped rapidly within 8 h postpartum. It is concluded that estrone sulfate, rather than estrone, is the predominant plasma estrogen in late pregnancy in the cow.

Comparison of an all-aqueous automated urine pregnancy oestrogen method with one using organic solvent extraction

A comparative study between an all-aqueous automated urine pregnancy oestrogen method and a well established one requiring organic solvent extraction showed good agreement ( r = 0.992). Advantages offered by the all-aqueous method include a faster rate of sample analysis and elimination of the difficulties of phase separation. The storage of urine for 5 days did not affect the oestrogen concentration measured by the all-aqueous method. Glucose, which reduced the apparent oestrogen concentration, was readily removed by treatment of the urine with borohydride, and treated urines showed good recoveries. The recovery of oestrogen was inadequate when glucose was removed from urine by incubation with yeast, possibly due to the formation of acetaldehyde.

An Investigation into the Automated Measurement of Urinary Oestrogens in Pregnancy

Changes in the relative sensitivity of reaction oestrone, oestradiol, oestriol, and their monoglucuronides due to changes in reaction temperature and the acid a nd quinol concentrations of Kober's reagent have been investigated by means of an automated system. Similar investigations have been carried out with a number of standardized pregnancy urines. All measurements have been made with reference to an oestriol-16(beta-D-glucuronide)standard. These changes have been examined with trichloracetic acid and p-nitrophenol in Ittrich's reagent. The importance of the final acid concentration has also been examined. As a result of these investigations a modified scheme is suggested which gives maximal sensitivity to oestriol conjugates and minimal sensitivity to oestradiol conjugates, and may be calibrated by using an oestriol conjugate as a primary standard. The effect of varying the concentration of trichloracetic acid and p-nitrophenol in Ittrich's reagent has been examined under these modified conditions. More than 200 urines have been assayed by this method and the results compared with those obtained by the present automated procedure. The effect of dilution on many of these specimens has also been examined.

Study on metabolic pathway from dehydroepiandrosterone sulfate to estrogen in late pregnancy (author's transl)

To investigate the metabolic pathway from dehydroepiandrosterone sulfate (DHAS) to estriol (E3) in late human pregnancy, DHAS (50 to 100 mg) was given intravenously or intraamniotically to 13 volunteers (from cases of normal pregnant women, pregnant women with a live anencephalic fetus, intrauterine fetal death or hydatidiform mole and a patient complicated with cancer of the cervix). Urinary estrogens, serum unconjugated estrogens and urinary dehydroepiandrosterone (DHA) and 16alpha-hydroxy-dehydroepiandrosterone (16alpha-OH-DHA) were measured before and after injection. Brown's method (1955) has been used to measure urinary three fractions of estrogens, estrone (E1), estradiol (E2) and estriol (E3). Serum unconjugated estrogens, estrone (SE1), estradiol (SE2) and estriol (SE3) were determined by a radioimmunoassay technique (a modification of the method of Makino, 1973). Urinary DHA and alpha-OH-DHA were separated by a modification of the method of Lakshmanan and Lieberman (1954) and by thin layer chromatography, and estimated by the method of Oertel and Eiknes (1959). Results obtained were as follows: (1) In seven cases of pregnancy with a live anencephalic fetus the excretion of urinary estriol was very low and the ratio of E3/E1+E2 was much less than that in normal pregnancy. (2) In five women with a live anencephalic fetus the effect of intravenously injected DHAS was studied. In each case there was a remarkable in urinary E3, E1 and E2, while no remarkable difference between the ratio of E3/E1+E2 before and after administration of DHAS was found. (3) DHAS was given intraamniotically to two women with a live anencephalic fetus. A greater rise of the ratio of E3/E1+E2 after administration of DHAS was found, compared to the control. (4) DHAS circulating in the maternal organism is converted to E3 largely via a phenolic pathway (DHAS-E1-E3), whereas DHAS circulating within the feto-placental compartment is converted to E3 via both phenolic and neutral intermediates (DHAS-16alpha-OH-DHAS-E3). (5) The ratio of urinary 16alpha-OH-DHA/DHA in pregnancy with a live anencephalic fetus was greater than that in non-pregnant woman. This suggests that 16alpha-hydroxylase activity in pregnancy is elevated. (6) Increases in serum unconjugated E1, E2 and E3 after intravenous administration of DHAS in three pregnant women with a live anencephalic fetus were found.

Estrogen Excretion in High-risk Pregnancy: A Comparison of Two Assay Procedures

To assess the clinical significance of acid-labile estrogens in high-risk pregnancy, urinary excretion of estrogen in 197 patients was measured by the Cohen ammonium sulfate precipitation method and by the Brown acid hydrolysis technic and the results were compared. The methods gave parallel results and both had essentially the same predictive value in assessing impairment of function of the fetoplacental unit. There was no evidence of an abnormally high concentration of acid-labile estrogens in the urines of 24 diabetic patients in this series.

Comparison of Plasma and Urinary Oestrogens in Pregnancy

Summary: Prior to the introduction into the hospital of plasma oestrogen estimations as a routine test in pregnancy, oestrogens were estimated simultaneously in urine and plasma in all inpatients and in a random selection of outpatients for a trial period. A total of 524 estimations were performed on 382 patients. The urine and plasma results were correlated with each other and with length of gestation, clinical disorders and birth weight in order to evaluate the suitability of plasma oestrogen estimations as a routine feto‐placental function test to replace 24‐hour urinary oestrogen excretion.

A radioimmunoassay for plasma unconjugated estrogens in normal pregnancy

After extraction, unconjugated estrone, estradiol, and estriol were separated with celite chromatography, with methanol-water as stationary phase, and measured by radioimmunoassay (RIA) using an anti-E1, 17β-hemisuccinate antibody. Separation of bound from free hormone was achieved by dextran-coated charcoal. The precision of the method is approximately 10 per cent for E1 and E3 and 15 per cent for E2. Ten women were followed throughout pregnancy. During the first trimester, plasma values of E1, E2, and E3 were low; then there was a regular increase of plasma E1 and E2 to week 39; estriol showed a biphasic increase. This observation is confirmed by the changes in theE2E3ratio, which tended to decrease from week 20 to 40 of gestation.

A comparison of a manual and a simple automated technique for the estimation of total oestrogens in pregnancy urine

A comparison of a simple automated method for total urinary oestrogens (“oestriol”) in pregnancy with a reputedly specific manual technique showed that the results obtained using the automated method were significantly higher than those found using the manual method. This discrepancy was found to be largely, if not totally, due to losses occurring during the manual procedure, implying that the automated method gives the more accurate result.

Comparison of an Automated Fluorimetric Method with Two Manual Methods for the Determination of Pregnancy Oestrogens

Three methods of determining urinary oestrogens are compared. Manual methods are better for intermittent demand but an automated method is desirable when more than 50 analyses per week are required.

Estimation of total estrogens in early pregnancy by column chromatography

The determination of Total Urinary Estrogens in early pregnancy (first trimester) using the Ittrich-Kober assay requires additional purification steps to remove impurities, which in later pregnancy are reduced by dilution. The problem was resolved by the use of the Sephadex G-15 columns after acid or enzymatic hydrolysis. The first part of the study was devoted to both conventional and rapid enzymatic hydrolysis of samples followed by adsorption on G-15 columns. The second part dealt with the use of acid hydrolysis and the same type of columns. A further study compared the results obtained on analysis of the ethyl acetate eluates from acid-hydrolyzed urines which had been partitioned between toluene and 1N NaOH and also those eluates which were directly dissolved in 1N NaOH. The results of these studies indicated that the level of neutral steroidal interference had been reduced in all cases. The purity ratios of results obtained using the G-15 column technique showed a marked improvement over those obtained by the present Cohen extraction procedure.