Lower E2 Concentrations Research Articles

Rapid and sensitive detection of 17β-estradiol in environmental water using automated immunoassay system with bacterial magnetic particles

A fully automated immunoassay of 17β-estradiol (E2) was performed using anti-E2 monoclonal antibody immobilized on bacterial magnetic particles (AntiE2-BMPs) and alkaline phosphatase-conjugated E2 (ALP-E2). E2 concentration in environmental water samples was evaluated by decrease in luminescence based on competitive reaction. A linear correlation between the luminescence intensity and E2 concentration was obtained between 0.5 and 5 ppb. The minimum detectable concentration of E2 was 20 ppt. All measurement steps were done within 0.5 h. The analysis of environmental water samples by a commercially available ELISA kit and the BMP-based immunoassay gave good correlation plots with a correlation efficient of 0.992. These results suggest that the fully automated system using the BMP-based immunoassay has some advantages in the high rapidity and sensitivity of the measurement. This system will enable us to determine low E2 concentrations without sample condensation.

Global analysis of ligand sensitivity of estrogen inducible and suppressible genes in MCF7/BUS breast cancer cells by DNA microarray.

To obtain comprehensive information on 17beta-estradiol (E2) sensitivity of genes that are inducible or suppressible by this hormone, we designed a method that determines ligand sensitivities of large numbers of genes by using DNA microarray and a set of simple Perl computer scripts implementing the standard metric statistics. We used it to characterize effects of low (0-100 pM) concentrations of E2 on the transcriptome profile of MCF7/BUS human breast cancer cells, whose E2 dose-dependent growth curve saturated with 100 pM E2. Evaluation of changes in mRNA expression for all genes covered by the DNA microarray indicated that, at a very low concentration (10 pM), E2 suppressed approximately 3-5 times larger numbers of genes than it induced, whereas at higher concentrations (30-100 pM) it induced approximately 1.5-2 times more genes than it suppressed. Using clearly defined statistical criteria, E2-inducible genes were categorized into several classes based on their E2 sensitivities. This approach of hormone sensitivity analysis revealed that expression of two previously reported E2-inducible autocrine growth factors, transforming growth factor alpha and stromal cell-derived factor 1, was not affected by 100 pM and lower concentrations of E2 but strongly enhanced by 10 nM E2, which was far higher than the concentration that saturated the E2 dose-dependent growth curve of MCF7/BUS cells. These observations suggested that biological actions of E2 are derived from expression of multiple genes whose E2 sensitivities differ significantly and, hence, depend on the E2 concentration, especially when it is lower than the saturating level, emphasizing the importance of characterizing the ligand dose-dependent aspects of E2 actions.

Distinct signaling pathways mediate stimulation of cell cycle progression and prevention of apoptotic cell death by estrogen in rat pituitary tumor PR1 cells.

Estrogens control cell growth and viability in target cells via an interplay of genomic and extragenomic pathways not yet elucidated. Here, we show evidence that cell proliferation and survival are differentially regulated by estrogen in rat pituitary tumor PR1 cells. Pico- to femtomolar concentrations of 17beta-estradiol (E2) are sufficient to foster PR1 cell proliferation, whereas nanomolar concentrations of the same are needed to prevent cell death that occurs at a high rate in these cells in the absence of hormone. Activation of endogenous (PRL) or transfected estrogen-responsive genes occurs at the same, higher concentrations of E2 required to promote cell survival, whereas stimulation of cyclin D3 expression and DNA synthesis occur at lower E2 concentrations. Similarly, the pure antiestrogen ICI 182,780 inhibits estrogen response element-dependent trans-activation and cell death more effectively than cyclin-cdk activity, G1-S transition, or DNA synthesis rate. In antiestrogen-treated and/or estrogen-deprived cells, death is due predominantly to apoptosis. Estrogen-induced cell survival, but not E2-dependent cell cycle progression, can be prevented by an inhibitor of c-Src kinase or by blockade of the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase signaling pathway. These data indicate the coexistence of two distinguishable estrogen signaling pathways in PR1 cells, characterized by different functions and sensitivity to hormones and antihormones.

Estradiol distribution during the development and expression of reproductive structures in Populus tremuloides Michx.

Estradiol (E2) was measured in spring and winter tissues in several populations of dioecious Populus tremuloides Michx. and in four trees with perfect flowers. A correlation between the concentration of E2 and sex expression was observed. In catkins, E2 concentrations increased before anthesis, peaked during flowering, and decreased as flowers matured. The increases were concurrent with sporogenesis and development of gametophytes. Statistically significant seasonal variation in E2 concentration was also evident. Dormant winter tissues showed significantly lower E2 concentrations than spring tissues. Branches exposed to relatively more light had significantly higher E2 content in both spring and winter. Seasonal variation in E2 content was also observed in trees of the same sex, among branches of the same tree, and among different organs.

Effects of pulp and paper mill effluents on reproductive success of largemouth bass

This study evaluated the effects of bleached and unbleached kraft mill effluent on reproductive success of largemouth bass (Micropterus salmoides). Bass were exposed to effluent concentrations (0, 10, 20, 40, or 80%) for 28 and 56 d. Parameters measured included hepatosomatic index (HSI) and gonadosomatic index (GSI) and plasma concentrations of 17beta-estradiol (E2), 11-ketotestosterone (11-KT), and vitellogenin (VTG). At the end of the 56-d period, bass were moved to hatchery ponds to evaluate spawning success. Spawning mats with eggs either were brought indoors for evaluation of fecundities, hatchabilities, and egg and fry size (measured at age 3 d), or were left in ponds and fry number and size recorded (average age of 14 d). Effluent exposure was verified by measuring resin acids (isopimaric, abietic. and dehydroabietic acids) in bile. Compared to controls, exposed bass had greater concentrations of resin acids in bile. In general, exposed females had lower concentrations of E2 and VTG (> or = 20% effluent), whereas males had lower concentrations of 11-KT (> or = 20% effluent) and increased E2 (> or = 20% effluent). The HSI values increased in females (> or = 10% effluent), and GSI values decreased in both sexes (> or = 40% effluent). Fecundity, egg size, and hatchability did not differ across treatments, but an increase in the frequency of fry abnormalities and a decrease in fry weights was observed at effluent exposures of 40% and higher. However, results from the pond study, revealed a significant reduction in fry growth and survival (> or = 10%). This decline may have been caused by an increased frequency of deformities, in conjunction with alterations of growth. These changes could have resulted from alterations in egg quality because of failure of parental reproductive systems, from acute embryo toxicity after translocation of contaminants from the mother to the developing embryo, or from both.

Effects of Dioxin and Estrogen on Collagenase-3 in UMR 106-01 Osteosarcoma Cells

Since estrogen is important in preventing osteoporosis in postmenopausal women and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an estrogen antagonist in reproductive tissues, we investigated the effects of 17β-estradiol (E2) and TCDD on collagenase-3 secretion using parathyroid hormone (PTH)-stimulated UMR 106-01 cells, a rat osteoblastic osteosarcoma cell line. Whereas E2 or TCDD had no effect on UMR cells in the absence of PTH, cells grown in the presence of 10−7 M PTH, which induces a dramatic 30-fold increase in collagenase-3 secretion, surprisingly demonstrated a further stimulation of collagenase-3 secretion in the presence of TCDD or E2. However, the potentiating response was biphasic; i.e., at higher concentrations of E2 or TCDD, there was no enhancement of the PTH effect. PTH induces multiple effects on UMR cells, including inducing collagenase-3 mRNA transcription and regulating its extracellular abundance through a specific receptor and endocytosis. Thus, we investigated the ability of TCDD or E2 to stimulate the induction of collagenase-3 mRNA using Northern analysis. As previously reported, PTH dose dependently induced collagenase-3 mRNA after 4 h of treatment. There was little effect of TCDD or E2 on PTH-induced levels of collagenase-3 mRNA. These data could not account for the final effects on secreted collagenase-3. We postulated that low concentrations of E2 and TCDD may downregulate the collagenase-3 endocytotic two-step receptor-mediated process that includes the LDL-receptor-related protein to enhance the effects of PTH. However, this was not the case. Therefore, we conclude that low concentrations of TCDD and estrogen alter translation or secretion of PTH-stimulated collagenase-3.

A rapid and sensitive reporter gene that uses green fluorescent protein expression to detect chemicals with estrogenic activity.

A reporter gene sequence was constructed within a eukaryotic expression vector. The altered plasmid contained 2 sequential estrogen response elements (ERE) coupled to a human phosphoglycerate kinase (PGK) promoter inserted upstream from a cDNA sequence encoding enhanced green fluorescent protein (GFP) with a 3'-polyadenylation signal. The plasmid was linearized and transfected into MCF-7 cells, a human breast cancer-derived line that expresses the estrogen receptor (ER). No selectable marker was present in the plasmid, requiring stably transfected cells to be selected by fluorescence-activated cell sorting based on GFP expression after the cells were treated with 10(-9) M 17beta-estradiol (E2). Stably transfected MCF-7 cells (MCF7-ERE) exhibited 2000-3000 times more fluorescence at 488 nm excitation and 512 nm emission than non-transfected cells. MCF7-ERE cells exhibited a linear increase in GFP expression induced over a range of 10(-12) M E2, a concentration giving 2 times the background expression, to maximal expression at 3 x 0(-10) M E2. From the maximal level, GFP expression plateaued, and then declined when E2 was increased to the highest concentration tested, 10(-7) M. 4-Hydroxytamoxifen (TFN-OH) treatment of cells produced a dose-dependent inhibition of E2-induced GFP expression, indicating the interaction of ER in the regulation of GFP gene expression. A series of estrogenic chemicals were evaluated for their capacity to induce GFP expression in MCF7-ERE cells, showing induced expression of GFP at concentrations 2-4 log units higher than the E2 concentration giving maximal GFP expression. The ERE-PGK-GFP reporter gene system is capable of rapid GFP expression in the presence of low concentrations of E2, and of quantifying estrogenicity of chemicals compared with a standard curve of the natural ligand, 17beta-estradiol.

The Relationship of Blood Progesterone and Estrogen Concentrations on the Day Before and the Day of Frozen-Thawed Embryo Transfer to Pregnancy Rate in Japanese Black Beef Cattle

The relationship of blood progesterone (P) and estradiol- 17β (E2) concentrations to the pregnancy rates in Japanese Black beef cattle recipients was investigated by determining blood P and E2 concentrations on the day before (day 6; day 0=onset of estrus) and the day of embryo transfer (day 7). Embryos were thawed by the stepwise method and transferred on day 7. The pregnancy rate showed a tendency toward increase with increasing P concentrations on both days 6 and 7 of embryo transfer. There was no significant correlation between the blood E2 concentration on day 6 and the pregnancy rate, wthereas pregnancy rate tended to rise when the blood E2 concentration on day 7 was low. The relationships of the blood E2/P ratio (× 103) on days 6 and 7 to the pregnancy rate were investigated. When the E2/P ratio was ≥1.0, the pregnancy rate tended to decrease. The bovine recipients, which showed poorly development CL, high blood E2/P ratio and coexistence of follicle ≥1.0 in diameter with CL, showed a tendency toward decrease in the pregnancy rate. From these observations, it is supposed to be important to select bovine recipient with the high bood P concentration and with the low blood E2 concentration on days 6 and 7 as bovine recipients for improvement of the pregnancy rate in bovine frozen-thawed embryo transfer.

Detection of estradiol and testosterone in hair of cattle by HPL/EIA

This study concerns the detection of natural steroid hormones in hair of cattle. Estradiol (E2) and testosterone (T) were chosen as representatives of estrogens and androgens. In particular, the influence of age, sex and hair pigmentation on the steroid concentrations was investigated. Samples were obtained from numerous steers, cows, bulls, and female and male calves. The extraction procedure for E2 and T from hair comprised liquid-liquid and solid-phase extraction and was followed by an essential high-performance liquid chromatography (HPLC) step for further purification of the extracts. Final quantification was performed with specific enzyme immunoassays (EIA). Lower E2-concentrations were detected in the hair of some steers, cows, and bulls (approximately 1 ng/g), in several of these hair samples the concentrations of E2 were below the limit of detection. Testosterone was measured in the hair of steers (approximately 3 ng/g), cows (approximately 6 ng/g), and bulls (in average 15 ng/g). There was a significant difference in the testosterone concentrations of white (approximately 8 ng/g) and of black hair (approximately 33 ng/g) of bulls. In hair from all male and female calves, E2 and T were measured. The concentrations amounted approximately to 9 ng E2/g and 3 ng T/g for female calves and to 5 ng E2/g and 7 ng T/g for male calves. There was no significant influence of sex or hair colour on the steroid concentrations in hair of calves. The results suggest that the method is a powerful means to detect natural steroid hormones in hair of animal origin.

Steroid sulphotransferase and 17beta-hydroxysteroid dehydrogenase activities in Ishikawa human endometrial adenocarcinoma cells.

The present studies concern sulphotransferase activities for estrogens and other steroids, and 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activities for estrogens in Ishikawa endometrial adenocarcinoma cells. When physiological concentrations of various estrogens (estrone, estradiol, estriol) are incubated, most of the transformation product is the respective sulphate. The sulphotransferase activity is very rapid, and 2 h after incubation 70-95% are converted to the sulphated form. Sulphates are found exclusively in the culture medium, which suggests that as soon as the sulphate is biosynthesized it is secreted to the medium. Comparative data using neutral steroids (dehydroepiandrosterone, testosterone, and pregnenolone) show that sulphotransferase activity for these compounds is very limited. In another series of studies, 17beta-HSD activity was explored for the interconversion estrone estradiol. At low concentrations (5 x 10(-9)-5 x 10(-8) M), when estradiol (E2) is incubated, most of the unconjugated material remains as E2 in the cellular compartment, but at high concentrations (5 x 10(-7)-5 x 10(-6) M) a great proportion (70-80%) of the E2 is converted to estrone (E1). On the other hand, after incubation of E1 at all concentrations most remained as unchanged E1. It is suggested that, in Ishikawa cells, at very low concentrations of E1 or E2, sulphotransferases are predominant, but when this enzyme is saturated 17beta-HSD activity is orientated to the oxidative form.

Biphasic estrogen response on bovine adrenal medulla capillary endothelial cell adhesion, proliferation and tube formation.

Abnormal angiogenesis underlies many pathological conditions and is critical for the growth and maintenance of various types of tumors, including hormone-dependent cancers. Since estrogens are potent carcinogens in humans and rodents, and are involved in regulating angiogenesis, this study was designed to examine the effect of estrogen on the behavior of an established bovine capillary endothelial cell line, a simple and physiologically relevant model of the capillary wall. The results demonstrate that 17beta-estradiol (E2), at different conditions, exerts both stimulatory and inhibitory effects on endothelial cell adhesion, proliferation and tube formation in vitro. Utilizing a cellular attachment assay, chronic exposure to nanomolar concentrations of E2 (i.e. 1 and 10 nM) increased endothelial cell adhesion significantly compared to vehicle treated controls. Cellular adhesion was inhibited by micromolar concentrations of E2. Cell count, PCNA immunohistochemistry and Western blot analysis demonstrated enhanced cell proliferation at low E2 concentration in estrogen-deplete medium. Inhibition of cellular proliferation was observed in both estrogen-replete and deplete medium at higher E2 concentrations (i.e. 1 and 10 microM). Furthermore, in vitro tube formation increased up to 3.0 fold in the presence of 10 nM and higher E2 concentrations. The present observations indicate that in vitro regulation of capillary endothelial cell adhesion, proliferation and capillary tube formation by estrogen, are dose dependent.

Effect of estradiol on cytokine secretion by proteolipid protein-specific T cell clones isolated from multiple sclerosis patients and normal control subjects.

The ability of estradiol (E2) to modulate the secretion of cytokines by CD4+ T cells was investigated using neuroantigen-specific T cell clones isolated from normal control subjects and patients with the demyelinating disease, multiple sclerosis. In the presence of E2, the majority of the tested clones showed a dose-dependent enhancement of Ag-stimulated IL-10 secretion. The secretion of IFN-gamma was also enhanced, although the peak enhancement occurred at lower E2 concentrations and at lower magnitude than observed for IL-10. By contrast, the effect of E2 on Ag-stimulated secretion of TNF-alphabeta was biphasic, with enhancement occurring at low doses, and inhibition present at high concentrations. E2 had no effect on the secretion of IL-4 or TGF-beta. These data indicate that E2 is capable of modulating both pro- and anti-inflammatory activities of CD4+ T cells and thus has the potential to influence the outcome of CD4+ T cell-mediated immune responsiveness.

A transcriptionally active estrogen receptor mutant is a novel type of dominant negative inhibitor of estrogen action.

We have characterized a human estrogen receptor (ER) mutant, V364E, which has a single amino acid substitution in its hormone-binding domain. This ER mutant is fully active or even superactive at saturating levels of estradiol (10(-8) M E2) yet has the capacity to act as a strong dominant negative inhibitor of the wild type ER. In transient transfection assays using ER-negative Chinese hamster ovary (CHO) cells and two different estrogen response element (ERE)-containing promoter reporter genes, V364E treated with 10(-8) M E2 exhibited approximately 250% and 100% of the activity of the wild type ER with these two promoter contexts, respectively. Despite the high activity of V364E when present alone in cells, coexpression of both V364E and wild type ER causes a significant decrease in overall ER-mediated transcriptional activity. On the TATA promoter, where V364E was more inhibitory, estrogen-stimulated activity was reduced by approximately 50% at a 1:1 ratio of mutant to wild type ER expression vector, and at a 10:1 ratio, 75% of ER activity was inhibited. V364E was expressed at lower levels than wild type ER and has a approximately 40-fold lower affinity for E2 compared with wild type ER. In promoter interference assays, V364E exhibited a strict dependence upon E2 for binding to an ERE. Surprisingly, even when V364E was unable to bind to ERE DNA (i.e. either at low E2 concentration or by mutation of its DNA-binding domain), this mutant retained full dominant negative activity. This highly active ER mutant is, thus, able to repress ER-mediated transcription when the mutant and wild type ER are present together in cells, even without DNA binding. Since competition for ERE binding and the formation of inactive heterodimers cannot fully account for the dominant negative activity of V364E, it is probable that altered interactions with proteins important in ER-mediated transcription play a key role in the repression of transcription by V364E. The properties and probable mechanism of action of V364E distinguish it from other previously described dominant negative inhibitors, in which competition for cis-acting DNA elements by transcriptionally inactive receptors played a large role in the resultant dominant negative phenotype.

Regulation by prostaglandin E2 of interleukin release by T lymphocytes in mucosa.

Regulation of immune cell activation in lymphocyte-bearing human tissues is a pivotal host function, and metabolites of arachidonic acid (prostaglandin E2 in particular) have been reported to serve this function at non-mucosal sites. However, it is unknown whether prostaglandin E2 is immunoregulatory for the large lymphocyte population in the lamina propria of intestine; whether low (nM) concentrations of prostaglandin E2 modulate immune responses occurring there; and whether adjacent inflammation per se abrogates prostaglandin E2's regulatory effects. To address these issues, intestine-derived lymphocytes and T hybridoma cells were assessed, T cell activation was monitored by release of independently quantitated lymphokines, and dose-response studies were performed over an 8-log prostaglandin E2 concentration range. IL-3 release by normal intestinal lamina propria mononuclear cells was reduced (up to 78%) in a dose-dependent manner by prostaglandin E2, when present in as low a concentration as 10(-10) M. PGE2 also inhibited (by > or = 60%) mucosal T lymphocytes' ability to destabilize the barrier function of human epithelial monolayers. Further, with an intestine-derived T lymphocyte hybridoma cell line, a prostaglandin E2 dose-dependent reduction in IL-3 and IL-2 (90 and 95%, respectively) was found; this was true for both mitogen- and antigen-driven T cell lymphokine release. Concomitant [3H] thymidine uptake studies suggested this was not due to a prostaglandin E2-induced reduction in T cell proliferation or viability. In contrast, cells from chronically inflamed intestinal mucosa were substantially less sensitive to prostaglandin E2, e.g., high concentrations (10(-6) M) of prostaglandin E2 inhibited IL-3 release by only 41%. We conclude that prostaglandin E2 in nM concentrations is an important modulator of cytokine release from T lymphocytes derived from the gastrointestinal tract, and it may play a central role in regulation of lamina propria immunocyte populations residing there.

Progesterone and Estradiol Interaction in the Regulation of Rat Uterine Weight and Estrogen Receptor Concentration

Autologous down-regulation of hormone receptors has been shown for several steroid hormones. We have previously shown estradiol (E2) regulates estrogen receptor (ER) in ovariectomized (OVX) rats. These studies have been extended to investigate the interaction between progesterone (P) and E2 in the regulation of ER and uterine weight. We implanted Silastic capsules containing varying concentrations of E2 (0.0005 mg E2/ml to 5.0 mg E2/ml of sesame oil) into adult female Sprague-Dawley rats one week after OVX. Simultaneously with implantation, P injections were started (sc in sesame oil) at doses of 1-40 mg/day for three days. In the absence of P, the 0.05 mg E2/ml implant significantly increased total ER levels (measured by cytosol and nuclear exchange assays) by 25%, while the two highest concentrations of E2 (0.5 and 5.0 mg E2/ml) significantly decreased cytosol and total ER levels by at least 40%. No P dose altered ER levels in OVX rats or in rats given E2 implants of 0.01 mg E2/ml or lower. At E2 implant concentrations of 0.05 mg E2/ml and higher, P decreased total ER levels 30%-50% compared to the appropriate E2-only controls. P increased uterine weight by 25% in OVX controls and in rats treated with E2 implants of 0.01 mg E2/ml and below. In contrast, P inhibited uterine weight gain induced by 0.05-5.0 mg/E2 ml implants by 20%-30%; maximal inhibition occurred at 5 mg/day of P and above. These data demonstrate that P increases uterine weight but does not alter ER concentration in rats with low E2 levels (OVX or low E2 concentration implants) but decreases uterine weight and down-regulates ER at higher E2 levels, regardless of whether ER is up-regulated or down-regulated by E2.

Circulating concentrations and pattern of luteinizing hormone and follicle-stimulating hormone in circulation are changed by the circulating concentration of 17 beta-estradiol in the bovine male and female.

The objectives of the present study were 1) to determine whether 17 beta-estradiol (E2) regulation of tonic secretion of LH and FSH is sexually differentiated in the bovine and 2) to evaluate the effects of various physiological concentrations of E2 on the profiles and concentrations of gonadotropins in circulation. This was accomplished by administering different numbers of implants containing E2 to gonadectomized bovine males and females. Mean age at initiation of the study was 18.5 mo. Animals received 1, 2, 4, 8, or 16 implants of E2 or a sham implantation. Mean concentrations of LH in circulation and amplitude of LH pulses were similar between males and females after administration of E2. There was a cubic response for mean concentrations of LH and amplitudes of LH pulses across the dosages of E2 administered; lower concentrations of E2 had little effect, whereas higher concentrations of E2 suppressed both mean LH and amplitude of LH pulses. A linear decline in frequency of LH pulses occurred as concentrations of E2 in circulation increased. A treatment x sex interaction resulted for mean concentrations of FSH in circulation. Low doses of E2 resulted in a greater enhancement of circulating concentrations of FSH in males than in females. Tonic secretion of LH in bovine males and females responded in a similar manner to administration of various physiological concentrations of E2; however, a differential response between sexes was observed for FSH.

Effects of Chronic Exposure to Estradiol on Ovarian Cyclicity in C57BL/6J Mice: Potentiation at Low Doses and Only Partial Suppression at High Doses1

Long-term exposure to ovarian hormones contributes to age-related changes in estrous cyclicity in rodents. Estrogens are implicated in this process, but the concentration of estrogen required to exert these effects is not well established. Also, although estrogens are presumed to alter vaginal cyclicity by affecting the hypothalamic-pituitary axis, they may also impair the ability of the vaginal epithelium to cornify. To address these issues, young and middle-aged ovariectomized (ovx) C57BL/6J mice were exposed for 7-10 wk to plasma levels of estradiol (E2) at one of three ranges (30-40, 50-80, or 120-160 pg/ml). Ovaries from young mice were then transplanted under the renal capsule, and vaginal cyclicity was monitored for 4 mo. Mice exposed to the lowest level of E2 not only failed to stop cycling, but had a higher monthly frequency of estrous cycles than did controls (nearly 1 extra cycle/mo). Mice exposed to the intermediate level of E2 showed no impairment in cyclicity. Although mice exposed to the highest concentrations of E2 showed no vaginal cyclicity, they continued to ovulate as evidenced by fresh, albeit reduced, numbers of corpora lutea. These results indicate that, in ovx mice, (1) chronic exposure to relatively low concentrations of E2 potentiates cyclicity, (2) very high levels of E2 are required to induce acyclicity, and (3) this acyclicity reflects vaginal as well as neuroendocrine alterations. The results also indicate that vaginal acylicity may be a poor indicator of ovulatory acyclicity in mice that have been chronically exposed to E2.

Cyclic ovarian function in recreational athletes

In 17 female recreational athletes, ovarian function was monitored using daily hormone measurements and serial ultrasound determinations. Whereas 11 out of 13 women of a control group showed estradiol (E2) maxima beyond 470 pmol/l, progesterone (P4) maxima of 19 nmol/l or more, and a luteal phase length of 9 days or more, only 10 out of 17 athletes satisfied these criteria. Six athletes showed disturbed follicular development, and one athlete showed luteal phase disturbance. Both athletes with disturbed menstrual function (n = 7) and athletes fulfilling the above-mentioned minimal criteria (n = 10) had lower E2 concentrations in all phases of the menstrual cycle (P less than 0.05). P4 concentrations were significantly decreased in the group with disturbed menstrual function (P less than 0.05). Maximal aerobic capacity in the two athlete groups was similar. Neither athlete group showed the expected increase in caloric intake compared with the sedentary controls. It is concluded that recreational running is associated with altered ovarian function. Inadequate nutritional adaptation may be a contributing factor.

Gonadal steroids modulate human monocyte interleukin-1 (IL-1) activity

Interleukin-1 (IL-1), a monocyte and macrophage product, is the mediator of a wide variety of immune responses, including fever, and increases during the luteal phase of the menstrual cycle, concomitantly with progesterone (P). These studies were undertaken to assess the possible relationship between steroidogenesis and IL-1 activity elaborated by human peripheral monocytes. IL-1 was measured with the D-10 thymocyte stimulation bioassay and dose response curves as a function of both estradiol (E2) and P were established. Low concentrations of both E2 (10(-9) M-10(-10) M) and P (10(-8) M-10(-9) M) resulted in maximal IL-1 stimulation. At higher concentrations of both E2 (10(-7) M) and P (10(-7) M-10(-5) M) there was a significant reduction (P less than 0.05) in IL-1 activity. However, neither E2 nor P production by human granulosa-luteal cells cultured with increasing amounts of human IL-1 (0 to 20 IU/ml) was affected in either the absence or presence of human chorionic gonadotropin (hCG, 5 IU/ml). Thus, human peripheral monocyte IL-1 activity appears to be modulated by gonadal steroids; however, a reciprocal relationship between IL-1 and gonadal steroidogenesis was not observed.

Gonadal steroids modulate human monocyte interleukin-1 (IL-1) activity

Interleukin-1 (IL-1), a monocyte and macrophage product, is the mediator of a wide variety of immune responses, including fever, and increases during the luteal phase of the menstrual cycle, concomitantly with progesterone (P). These studies were undertaken to assess the possible relationship between steroidogenesis and IL-1 activity elaborated by human peripheral monocytes. IL-1 was measured with the D-10 thymocyte stimulation bioassay and dose response curves as a function of both estradiol (E2) and P were established. Low concentrations of both E2 (10(-9) M-10(-10) M) and P (10(-8) M-10(-9) M) resulted in maximal IL-1 stimulation. At higher concentrations of both E2 (10(-7) M) and P (10(-7) M-10(-5) M) there was a significant reduction (P less than 0.05) in IL-1 activity. However, neither E2 nor P production by human granulosa-luteal cells cultured with increasing amounts of human IL-1 (0 to 20 IU/ml) was affected in either the absence or presence of human chorionic gonadotropin (hCG, 5 IU/ml). Thus, human peripheral monocyte IL-1 activity appears to be modulated by gonadal steroids; however, a reciprocal relationship between IL-1 and gonadal steroidogenesis was not observed.