Receptor and Biological Response to Estriol in the Fetal Uterus of Guinea Pig

Abstract

The binding of ³H-estriol was examined in the fetal uterus of guinea pig. The physico-chemical characteristics of the binding of ³H-estriol to macromolecules are similar to the typical receptor protein for estrogens. Different estrogens (estriol, estradiol, estrone and diethylstilbestrol) compete with this binding but progesterone and testosterone have no effect. The binding affinity has a Kd of 5.5 ± 1.6 ± 10^?10M. By ultra-centrifugation in sucrose gradient, two specific components with sedimentation coefficients of 8 and 45 are found. Competition studies suggest that the same specific binding sites may be present for estriol (E₃) and for estradiol. The s.c. administration of E₃ to the pregnant guinea pig (1 mg/day per kg body weight for 3 days) provokes two biological responses in the fetal uterus: a uterotrophic effect and a significant increase in the progesterone receptor. The increase in the fetal uterine weight is 50–70% in relation to the non-treated animals and the progesterone receptor concentration is 10–14 times higher than in the control animals. These effects are similar (or slightly higher) than in animals primed with equimolecular quantities of estradiol. In contrast, single daily injections of E₃ to newborn guinea pig, results only in weak uterotrophic activity.

It is concluded that estriol is capable of causing a biological response in the uterus during intra-uterine life.     

Autoradiographic studies on the fetal and newborn uteri of the guinea pig after injection of 3H-progesterone into non-treated and into estradiol-primed animals

Summary The localization and retention of radioactivity in the uteri of fetal and newborn guinea pigs was studied after subcutaneous injection of ³H-progesterone into intact and estradiol-primed animals. In the fetal uterus of the animals treated with estradiol, a significant increase in the accumulation of silver grains was observed, mainly localized in the stroma and myometrium, but very little is detected in the uterine gland. On the other hand, in the uteri of newborns, the effect of estradiol on radioactivity retention was significantly less intense and the radioactivity is mainly localized in the epithelium and the uterine gland. These data correlate well with the quantitative evaluation of the concentration of progesterone-specific-binding sites in the non-treated and in the estradiol-primed fetal and newborn guinea pigs.     

Biology and receptor interactions of estriol and estriol derivatives in vitro and in vivo

The biological effects of estriol (E3) have been studied in three estrogen targets, namely, the rat uterus in vivo and in vitro, in primary human endometrial cell cultures and in MCF-7 human breast cancer cells in culture. Studies on the temporal relationships between estrogen receptor binding and biological responses in the uterus using estriol and several more long-acting estriol derivatives, namely, 17α-ethynyl estriol, estriol-3-cyclopentyl ether, and 17α-ethynyl estriol-3-cyclopentyl ether, indicate that estriol is a short-acting compound with a brief duration of action. Estriol is a poor stimulator of uterine growth and plasminogen activator activity in vivo. Chemical modifications of the estriol molecule produce long-acting derivatives that result in a prolonged input of hormone receptor complexes into the nucleus and a prolonged and marked stimulation of uterine growth. In human endometrial cells in primary tissue culture, E₃ has 12% the affinity of estradiol (E₂) for cytosol estrogen receptor and it is quite effective yet slightly less potent than estradiol in stimulation of progesterone receptor synthesis. Low concentrations of E₃(10⁻¹⁰ M) stimulate growth of MCF-7 cells in vitro and dose-response curves show E₃ to be only slightly less effective than E₂. In these endometrial and breast cancer cell systems in vitro, there is no metabolism of E₃ while E₂ is metabolized to estrone.Hence, estriol is an effective estrogen in vitro. In vivo, it is short-acting, but it can be made a full estrogen agonist when given at a sufficiently high concentration or in a chemically modified form which prolongs its activity by enabling effective concentrations of the compound to be maintained in the blood and in target tissues.     

Biological responses of tamoxifen in the fetal and newborn vagina and uterus of the guinea-pig and in the R-27 mammary cancer cell line

The biological and morphological responses of tamoxifen were studied in two models: the uterus and vagina of fetal and newborn guinea-pigs: R-27 cells--a mammary cancer cell line (tamoxifen resistant) derived from the MCF-7 cancer cell line. Tamoxifen (TAM) alone or in combination with estradiol (E2) was administered to pregnant (50-52 days of gestation) or to newborn (2-day-old) guinea-pigs for a long period (12 days). TAM alone produced a great trophic effect on the uterus and vagina which was markedly enhanced when TAM was administered together with E2. Histological studies showed that TAM provokes morphological changes in both the endometria and the myometria and this effect was also greater when TAM was administered together with E2. In the fetal uterus and vagina, the ultrastructural studies showed that TAM induces morphological alterations in different cytoplasmic organelles. This effect was much more intense in newborns where TAM provoked a significant vacuolization of the epithelial cells. Concerning progesterone receptor (PR) in the fetal or newborn tissues (uterus or vagina) TAM provoked a less intense effect than those provoked by E2, but TAM did not block the effect provoked by E2. It was observed that [3H]TAM binds specifically to the estrogen receptor (ER) of fetal guinea pig uterus and this complex is partially recognized by a monoclonal antibody which recognizes the activated form of this receptor, supporting the suggestion that the biological action of TAM is mediated by the ER. The biological and ultrastructural effects provoked by TAM (1 X 10(-6) M), estriol (E3)(5 X 10(-8) M) and the combination of TAM + E3 were studied in the R-27 mammary cancer cell line in culture. E3 stimulated the PR content by 7-10 times. However, TAM did not provoke a significant decrease in the concentration of PR, and in the mixture of TAM + E3 the concentration of PR was of the same order as that in E3 treatment. Ultrastructural observations indicate an intense concentration of ribosomes in the pericytoplasmic area after exposure to E3 and with exposure to TAM an increase in vacuoles and a significant enlargement of the size of the mitochondria were observed. It is concluded that TAM in the target tissues of fetal and newborn guinea pigs acts as a real estrogen and in the R-27 mammary cancer cell line TAM does not block the effect provoked by E3, however it does provoke intense ultrastructural modifications.     

Intermediary metabolism of estriol in pregnancy

Estriol (E₃), the most abundant estrogen in pregnancy is produced predominantly in the placenta from androgen precursors of fetal origin. The estriol so formed is secreted efficiently into the maternal circulation where it is converted to 4 conjugates—estriol-3-sulfate (E₃-3S), estriol-16-glucosiduronate (E₃-16G), estriol-3-glucosiduronate (E₃-3G) and estriol-3-sulfate-16-glucosiduronate (E₃-SG). The order of renal clearances is E₃-16G > E₃-3G > E₃-3S ~ E₃-SG. Unconjugated E₃ and E₃-3G differ from the other forms of estriol in that their removal from the blood compartment is essentially irreversible. E₃-3S, E₃-16G and E₃-SG undergo interconversions during enterohepatic circulation and eventual partial conversion to E₃-3G. Following delivery of the fetus and placenta, unconjugated E₃ is no longer detectable in the maternal serum within l–2h, whereas the concentrations of the conjugates decline more slowly, the rates being determined by the rates of renal clearance and enterohepatic interconversions. E₃-3G levels were dramatically elevated in a case of Group C polycystic kidney disease, providing evidence that this conjugate is indeed an end-product of estriol metabolism.     

The biological role of estriol]

It was demonstrated on the uteri of women and guinea pigs that estriol (in vitro) possessed a marked affinity to the estradiol-binding system of human and guinea pig uteri; the activity of steroid-receptor interaction of estriol in vitro constituted 9.4% for guinea pigs and 17% for man in relation to the estradiol activity. Administration of estriol to guinea pigs in vivo in a dose of 0.25-0.5 mg led to a sharp reduction of the estradiol-binding capacity of the receptor system of the uterus. It is supposed that there existed a competitive relationship between estradiol and estriol for binding with the active centres of the receptor proteins of the uterus.     

Effect of estriol treatment on the menstrual cycle and prolactin secretion

In order to study the biological effects of estriol in women 20 mg estriol was administered daily to 7 young women. Plasma luteinizing hormone (LH), estradiol (E₂), progesterone (Pg) and prolactin (Prl) were measured during a treatment and a control cycle every second or third day. Further 3, 6 or 20 mg estriol was administered in a single dose to 5 women and plasma Prl, unconjugated and conjugated estriol (E₃) measured over 24 h at 2–3 h intervals. In 2 experiments with 20 mg E₃, blood samples were taken more frequently, over 6h.When 20 mg E₂ was administered daily, 2 of the 7 young women had anovulatory cycles. The mean plasma E₂ was lower during the follicular and ovulatory phases (P < 0.025) and mean plasma LH was higher (P < 0.005) during the luteal phase, when E₃ was given. Because of the 2 anovulatory cycles the mean Pg value during the luteal phase was lower (P < 0.05) during treatment. There was a slight decrease in mean Prl in 5 out of 6 women (P < 0.0005), but in only 1 woman was this decrease substantial (from a mean value of 27.6–18.9 ng/ml; P < 0.01). When 6 or 20 mg E₃ was administered orally in the morning a significant negative correlation (P < 0.01) between plasma Prl and unconjugated E₃ was found. The correlation coefficient was highest (r = −0.74) with 6mg E₃. When 3mg was administered no obvious effect on Prl section was seen. However, when results from all experiments with identical time schedules were pooled (two with 3 mg, two with 6 mg and one with 20 mg E₃) and the mean values for plasma Prl calculated and compared with the mean values obtained in 7 control experiments, it was found that E₃ administration in the morning almost abolishes the Prl rise during the following night. There was a statistically significant (P < 0.0125) decrease in the difference between the maximum value during the night and the minimum value during the day. The minimum value was significantly higher (P < 0.01) and the maximum value significantly lower (P < 0.025) after e₃) treatment, compared to the control values.It is concluded that long-term administration of 20 mg e₃ usually has only a slight but significant decreasing effect on mean plasma Prl concentration measured in the morning, before the next dose is taken. However, E₃ has an inhibiting effect on Prl secretion during the night and a stimulating effect during the day, if administered in the morning, resulting in a considerable reduction in the amplitude of the circadian rhythm. Continuous administration of high doses (20 mg/day) of E₃ may result in anovulatory cycles, but has little effect on plasma hormone values in the cycles which remain ovulatory.     

8α-estra-1,3,5(10)-triene-1,3,17β-triol as a special type of estrogen having a high vaginotrophic activity and a low uterotrophic activity in castrated mice

The vaginotrophic and uterotrophic activities of 1-OH-8α-E₂ and its acetate in comparison with E₂ and E₃ were assessed on the basis of the effect on weights, water/fat- and RNA/DNA-contents of mouse vagina and uterus.The multiple doses of 8α-steroids or E₃ sufficient to achieve a maximal effect on the vagina were not enough to stimulate the uterus fully. At various periods of time after multiple injections, 1-OH-8α-E₂ acetate was found to have a higher vaginotrophic potency than the uterotrophic potency, when compared with E₂ as a standard.The study on the time course of organ response to 8α-steroids, E₂ and E₃ after a single injection of daily dose, being equipotent when injected once daily for 3 days, demonstrated that 1-OH-8α-E₂ and E₃ were less vaginotrophic and uterotrophic than E₂ and had a short duration of action. 1-OH-8α-E₂ acetate in comparison with E₂produced a long-lasting vaginotrophic effect and an early regressing uterotrophic effect.It can be confirmed that 8α-steroids, like E₃, are a special type of estrogen having a high vaginotrophic activity and a low uterotrophic activity.     

Anti-estrogens in fetal and newborn target tissues

The antagonistic effects of progesterone and of the anti-estrogens, tamoxifen and nafoxidine, to estrogen responses were studied in the target tissues of fetal and newborn guinea pigs. In the fetal uterus, progesterone inhibits the stimulatory effect provoked by estradiol on uterine growth, on progesterone receptor and on the acetylation of nuclear histones. Progesterone also blocks the synthesis of new progesterone receptor protein in organ culture. Tamoxifen or nafoxidine (1 or 10mg/kg/day injected to the mother for 3 days) provoke a uterotrophic effect similar to that of estradiol (1 mg/kg/day injected to the mother for 3 days) but these anti-estrogens have a limited effect on the progesterone receptor. Tamoxifen given together with estradiol antagonizes the effect of the estrogen on the acetylation of histones but the anti-estrogens do not block the effect of estradiol on uterine growth. Histological studies show that both estradiol and tamoxifen provoke a dramatic hypertrophie and hyperplastic effect particularly in the uterine epithelium.In the newborn uterus (6-day old), tamoxifen (s.c. injection of 0.6μg/g body weight) and estradiol (injection of 30 ng/g body weight) provoke a similar uterotrophic effect and both have a limited effect on the progesterone receptor.In the fetal thymus estradiol provokes a selective decrease in the larger and actively proliferating lymphoid cells of the cortical zone. Tamoxifen has a similar effect but to a much lesser extent than estradiol. On the other hand, tamoxifen antagonizes the effect of estradiol on this fetal tissue.It is concluded that during fetal life progesterone antagonizes the effect of estradiol but tamoxifen can act as an agonist or an antagonist of estrogen action which is a function of the type of response or organ considered.     

Effect of estriol, estriol-3-sulfate and estriol-17-sulfate on progesterone and estrogen receptors of MCF-7 human breast cancer cells

The levels of progesterone receptors (PR [cytosol (Cy) and nuclear (N)] and estrogen receptors (ER) [cytosol and nuclear; occupied and unoccupied specific binding sites] were evaluated in the MCF-7 cancer cell line incubated with estriol (E3), estriol-3-sulfate (E3-3-S) or estriol-17-sulfate (E3-17-S) for 7 days in culture. Cells were grown in MEM medium containing 2 mM glutamine, 10% v/v dialysed calf serum and penicillin-streptomycin (100 U/ml) in the absence (control) or in the presence of 5 X 10(-8) M E3, E3-3-S or E3-17-S. The total PR (Cy + N) concentration which was 0.47 +/- 0.10 (SE) pmol/mg DNA in the non-treated cells, increased to 1.95 +/- 0.48 in the E3 and to 1.55 +/- 0.26 in the E3-3-S treated cells. No effect (PR: 0.47 +/- 0.15 pmol/mg DNA) was observed with the E3-17-S treatment. Total ER (Cy + N, occupied + unoccupied binding sites) in pmol/mg DNA +/- SE, were as follows: control 0.79 +/- 0.17; + E3: 0.33 +/- 0.09; +E3-3-S: 0.90 +/- 0.18 and +E3-17-S: 1.82 +/- 0.58. The measurement by radioimmunoassay of unconjugated estriol in the culture medium indicated that after incubation with E3-3-S, a fraction (0.5-1%) of the sulfate was hydrolyzed but no hydrolysis was observed in the incubations with E3-17-S. It is concluded that in the MCF-7 human mammary cancer cell line E3 and E3-3-S stimulate PR very significantly, but it is suggested that E3-3-S acts through the hydrolyzed E3. On the other hand, E3-17-S is inactive because it is not hydrolyzed. Consequently, E3-3-S can play an important role in the biological responses of this mammary cancer cell line.     

Relative distribution of estrone,estradiol and estriol between fetal and maternal perfusates during perfusions of human term placentas with labeled C19 precursors

Published results from in vivo experiments carried out in Rhesus monkeys and from in vitro perfusions of human term placentas have indicated that placental estradiol (E₂) is preferentially released towards the mother whereas estrone (E₁) is about evenly distributed between fetal and maternal circulation.In order to examine the distribution of estriol, relative to that of E₁ and E₂, we have now prepared [³H]16-hydroxyandrostenedione by incubation of [6,7-³H]androstenedione with Streptomyces roseochromogenus and perfused placental cotyledons with mixtures of these two labeled precursors. Measurement of the concentrations of tritiated E₁, E₂ and E₃ in the maternal and fetal perfusates, flowing at approx 10 and 5 ml/min, respectively, indicated that the distribution of E₃ is different from that of E₂ and resembles the distribution of E₁.The simple perfusion system being used shows differences in the distribution of various estrogens between fetal and maternal perfusates which may reflect the in vivo situation and offers the opportunity for experimental examination of various explanations for these differences, e.g. existence of specific carrier systems in the syncytial membranes, specific binding of the estrogens to secreted placental proteins, and actions of placental and decidual 17β-hydroxysteroid dehydrogenases.     

Effect of estrogens on dmba induced breast tumors

Evidence is presented for the anti-carcinogenic activity of estriol when this hormone is administered to 50–55 day old SD rats prior to treatment with DMBA. In control and estradiol treated animals, 85–100% of animals developed breast tumors regardless of dose of steroid. Low doses of estriol (1 μg/day) offered some protection against tumorigenesis but at levels exceeding 10μg/day only 20–35% of animals developed tumors even when observed for 180 days following DMBA ingestion. Furthermore, the mean time for tumor production is greatly increased in the presence of E₃. Short term (2 weeks) administration offered no protection against tumor formation, suggesting that the effect of estriol probably relates to the promotion stage of tumorigenesis.     

A rapid gas-liquid chromatographic method for the quantitation of urinary estrone, estradiol-17 , estriol, and pregnanediol throughout pregnancy

A rapid, sensitive and inexpensive method is presented for the determination of urinary estrone (E₁), estradiol-17β (E₂), estriol (E₃), and pregnanediol (P₂) in pregnancy urine. The assay involves enzymatic hydrolysis, ion-exchange chromstography, and final quantitation of the steroids as heptafluorobutyric anhydride derivatives in a gas Chromatograph. Twenty to 30 samples may be prepared for gas-liquid chromatography in one working day. For six samples, the results including gas-liquid chromatography and calculation can be obtained eight hours after receiving the urine specimens thus competing in speed with radioimmunoassays. The method is sensitive enough to allow urines from less than six weeks after the last menstrual period to be quantitated.     

Estriol metabolism in the baboon: analysis of urinary and biliary metabolites

The metabolism of i.v. estriol was investigated in two intact baboons and four with biliary fistulas. Urine and bile samples were collected periodically and the radioactivity extracted by Amberlite-XAD resin. Metabolites were separated and purified by a combination of DEAE-Sephadex chromatography, celite partition, specific enzyme hydrolysis of the conjugates and identification of the aglycones. The excretion and metabolism of estriol in the animals closely resembled those of the human. Intact animals excreted an average of 50% of the radioactivity in the urine during 12 hours and two animals with biliary drainage excreted an average of 40% in the urine and 49% in the bile. When the steroid was injected into the portal vein an average of 11.5% and 84% were excreted in the urine and bile, respectively.In the urine of intact animals, approximately 65.8% of the radioactivity was in the form of E₃-16G; 14.2% as E₃-3G; 13.4% as E₃-3S and 5.1% as E₃-3S-16G. Over 73% of biliary radioactivity from the peripheral injections was made up of E₃-3S-16G and 3.6% as E₃-16G and 8.3% as 3-sulfate. In the urine,however, 57% of the label was made up of E₃-16G. No radioactive E₃-3G was detected in the bile of any of the animals. Following simultaneous injection of ³H-E₃ peripherally and ¹⁴C-E₃ intraportally, the 3-glucosiduronate excreted in the urine was derived exclusively from the ³H-label. Based on the results obtained, the baboon has been shown to metabolize estriol in the same fashion as the human, with E³-3S-16G as the predominant biliary metabolite and E³-16G as the major urinary metabolite. As in the human, evidence was also found for an enterohepatic circulation of e³ in the baboon, 16-glucuronidation in the kidney, and extrahepatic (enteric?) formation of E³-3G. $\text{In vitro}$ incubation of the baboon liver yielded 94% of the total conjugate as E³-16G without any trace of E³-3G.     

Brain uptake and metabolism of estradiol benzoate and estrous behavior in ovariectomized guinea pigs

Groups of spayed guinea pigs were injected sc with tritiated estradiol benzoate in oil and killed at intervals varying from 12 to 120 hr later. The quantities of radioactivity with the mobility of estrone (E₁), estradiol-17β (E₂), and estriol (E₃) were estimated in plasma, hypothalamus, cortex, and cerebellum. Radiometabolites extracted from the hypothalamus and the cortex were identified by derivative formation and by isotope dilution techniques. The hypothalamus contained larger quantities of E₂ than any of the other tissues studied. The same pattern of uptake and decay of radioactivity was observed in all tissues. Concentration of total radioactivity was greatest 12 hr after injection and declined fairly regularly to minimal value at 120 hr. Unlike the hypothalamus and the cerebellum, in the cortex a large proportion of the radioactivity was present as E₁. ³H-estradiol benzoate was metabolized to ³H-estradiol by blood in vitro suggesting that the esterified form of the hormone is long lasting because of its slow release from the site of injection rather than its long half-life in the blood.Additional groups of spayed guinea pigs were tested for lordosis in response to fingering after injection of estradiol benzoate followed by progesterone at intervals varying from 12 to 120 hr. The expression of lordosis varied in a complex manner as a function of the interval between the injection of estradiol benzoate and progesterone. Maximum measures of lordosis were obtained when the interval between injections was 36 hr. The relation between behavior and the neural uptake of estrogens suggests that both the duration of estrogen action and the concentration of estrogens at the time the behavior is being displayed determine the character of the response.     

Inability of [3H]estriol to induce maximal cooperativity of the estrogen receptor

The interaction of [³H]estriol with the partially purified estrogen receptor from calf uterus shows positive cooperativity that is dependent upon receptor concentration and temperature. At a receptor concentration of 1 nM and 25°C the [³H]estriol-receptor cooperativity was low, the Hill coefficient (n_H) was 1.03 ± 0.02; however, with increasing receptor concentrations the receptor's cooperativity increased until at approximately intracellular receptor concentration (20 nM) the n_H = 1.20 ± 0.04. At 0°C and a receptor concentration of 10 nM the [³H]estriol-receptor interaction was highly cooperative, the Scatchard plot was convex and n_H = 1.58 ±0.04 while at 30°C the Scatchard plot approached linearity and n_H = 1.03 ± 0.02. In comparison, [³H]estradiol was capable of inducing, at 0 or 30°C and at a receptor concentration of 1 nM or greater, maximal receptor cooperativity, n_{H = 1.63}.These data demonstrate: (a) the receptor's conformation and binding mechanism change in a specific manner with temperature, so that receptor analysis at 0°C does not necessarily reflect the receptor's properties at biologically relevant temperatures; (b) the dependence of the receptor's cooperativity on receptor concentration, which suggests interaction between dissociable subunits; and (c) the lower cooperativity induced by estriol, in comparison with estradiol, which indicates estriol is less efficient in shifting the receptor toward a higher affinity or the activated state of the receptor.     

Experimental study on the estrogen-like effect of mercuric chloride

Although mercuric chloride has toxicity on reproductive system, it is uncertain if such toxicity is induced by estrogen-like effect. To study whether mercuric chloride has the estrogen-like effect and its relevant mechanism, proliferation assay of MCF-7 human breast cancer cells, uterotrophic assay, peroxidase activity assay and estrogen receptor competitive binding assay were conducted to screen the estrogen-like effect of mercuric chloride. The MCF-7 cells proliferated in the stimulation of mercuric chloride and got to the peak at 10⁻⁷ mol/l concentration. And this proliferation could be completely blocked by estrogenic antagonist ICI182.780. In addition, mercuric chloride could increase the weight of uterus of ovariectomized SD rats and the peroxidase activity of uterus complying with dose-effect relationship. However, mercuric chloride could not affect the binding of estradiol (E₂) to estrogen receptor (ER). So mercuric chloride exhibits the estrogen-like effect through binding and activating ER rather than bind to ER by competing with E₂.     

Effect of estriol on the structure and organization of collagen in the lamina propria of the immature rat uterus.

Estradiol produces both hypertrophic and hyperplastic changes in the uterus, and these changes are associated with alterations in the structure of collagen in the lamina propria. Estriol induces only hypertrophic responses in the immature rat uterus; its effects on collagen structure were characterized in this study. Light micrographs of Masson's trichrome-stained sections revealed that the intensity of the collagen stain in the lamina propria of the rat uterus was profoundly reduced, relative to that in controls, 4 h after estriol (40 micrograms/kg) administration. These changes were not evident 24 h after estriol administration. In control uteri, transmission electron micrographs revealed that the collagen fibers surrounding stromal cells formed dense collections of bundles that were seen throughout the extracellular matrix, whereas in tissues exposed to estriol 4 h earlier, large regions of the extracellular spaces were devoid of collagen bundles. The 4-h changes in collagen were eliminated when animals were pretreated with actinomycin D (8 mg/kg) or cycloheximide (4 mg/kg). Dense collections of collagen bundles were present in tissues 24 h after estriol treatment, and their appearance was not altered by actinomycin D or cycloheximide treatment. Alterations in collagen 4 h after hormone administration appeared to be estrogen-specific since dexamethasone (600 micrograms/kg) and dihydrotestosterone (400 micrograms/kg) had no effect. These data provide evidence that the changes in collagen structure in the uterus are associated with events that function during the hypertrophic growth responses induced by estrogens.     

Non-invasive detection and monitoring of estrus,pregnancy and the postpartum period in pygmy loris (Nycticebus pygmaeus) using fecal estrogen metabolites

Estrone-conjugates (E₁C) were measured in the feces of six female pygmy lorises (Nycticebus pygmaeus) during estrus (n = 12), pregnancy (n = 4) and the postpartum period (n = 3). Noninvasive feces collection permitted frequent sampling throughout estrus and pregnancy, without disturbance of animals. The estrous period was defined as an increase in fecal E₁C levels above an average of 70 ng/g feces with peaks above 100 ng/g feces obtained in consecutive fecal samples collected over a 6- to 11-day period between the end of July and the first third of October. Comparison of the periovulatory profile of E₁C and the stage of labial opening of the vagina revealed a high agreement (P < 0.001). In all pregnant females, an E₁C rise was found approximately 47 days postestrus, the source of which may be the growing fetal placental unit. Estimated gestation lengths ranged between 187 and 198 days (n = 4). Am. J. Primatol. 41:103–115, 1997. © 1997 Wiley-Liss, Inc.     

Hormone changes in relation to the time of fetal death after prostaglandin-induced abortion

The changes in unconjugated estradiol-17β and estriol, progesterone and chorionic somatomammotropin (HCS) in peripheral plasma have been studied in 18 women at 30-minute intervals following intra-uterine prostaglandin E₂ administration for therapeutic termination of second trimester pregnancy. The hormonal changes were related to the time of fetal death detected by the disappearance of fetal heart pulsations. Prostaglandin E₂ was given by the intra-amniotic route with urea (5 patients) or with intravenous oxytocin (5 patients), or by the extra-amniotic route with intravenous oxytocin (8 patients). Fetal death occurred rapidly with intra-amniotic PGE₂, but usually at a late stage with extra-amniotic PGE₂. Three fetuses in the extra-amniotic group died at or just before abortion. A variety of fetal heart changes were noted and the time of fetal death did not appear to influence the time of abortion within each treatment subgroup.Estradiol and estriol showed a slight but persistent fall over 24 hours prior to induction of abortion. A more rapid fall usually occurred after induction, with a consistent fall around the time of fetal death. Progesterone and HCS usually fell much less before and immediately after fetal death. A marked rise in estradiol sometimes occurred before fetal death, particularly in the intra-amniotic PGE₂ and urea subgroup. Estriol levels declined more rapidly before than after fetal death, whereas fetal death had less consistent effects on the other hormones. All hormones had usually fallen considerably at the time of abortion, and in some individuals marked fluctuations in hormone levels were seen.