Effects Of 17α-ethinylestradiol Research Articles

Effects of 17α-ethinyl estradiol (EE2) and removal potential by two microalgal species Chlorella vulgaris and Scenedesmus obliquus

17α-ethinyl estradiol (EE2) is the primary component in birth control pills and is highly bioavailable when taken orally. However, 80 % of the administrated dose is excreted un-metabolized in feces and urine, leading to its detection in water bodies and wastewater effluent from conventional treatment plants. EE2 negatively impacts on aquatic ecosystems, including disruption to the endocrine system of organisms, causing feminization in males, egg production and fertilization perturbation.Microalgae-based wastewater treatment is a promising biological approach for removing pollutants from the environment, including emergent and persistent contaminants. In this study, we evaluated the tolerance of two microalgal species Chlorella vulgaris (C. vulgaris) and Scenedesmus obliquus (S. obliquus) to various EE2 concentrations (0, 0.05, 0.10, 0.20, 0.30, 1.00, 8.0 and 22.0 mg L−1). Their potential to remove EE2 and the corresponding degradation kinetics were also assessed. The results showed that both species tolerated concentrations up to 8.0 mg EE2 L−1; however, at 22.0 mg EE2 L−1, C. vulgaris biomass decreased, and S. obliquus growth was inhibited. S. obliquus removed over 90 % of EE2 for most concentrations tested, while C. vulgaris achieved a maximum removal of 64 %. EE2 removal was attributed to microalgal biodegradation rather than sorption or bioaccumulation. The kinetic parameters determined that EE2 half-life was one day in S. obliquus culture and nine days in C. vulgaris. These findings confirmed that S. obliquus, especially, could reduce EE2 half-life in the environment, facilitating its removal. This information is valuable to understand EE2 degradation in aquatic ecosystems with microalgae presence.

Effects of 17α-ethinylestradiol on the neuroendocrine gonadotropic system and behavior of European sea bass larvae (Dicentrarchus labrax)

ABSTRACT The widespread use of 17α-ethinylestradiol (EE2), and other estrogenic endocrine disruptors, results in a continuous release of estrogenic compounds into aquatic environments. Xenoestrogens may interfere with the neuroendocrine system of aquatic organisms and may produce various adverse effects. The aim of the present study was to expose European sea bass larvae (Dicentrarchus labrax) to EE2 (0.5 and 50 nM) for 8 d and determine the expression levels of brain aromatase (cyp19a1b), gonadotropin-releasing hormones (gnrh1, gnrh2, gnrh3), kisspeptins (kiss1, kiss2) and estrogen receptors (esr1, esr2a, esr2b, gpera, gperb). Growth and behavior of larvae as evidenced by locomotor activity and anxiety-like behaviors were measured 8 d after EE2 treatment and a depuration period of 20 d. Exposure to 0.5 nM EE2 induced a significant increase in cyp19a1b expression levels, while upregulation of gnrh2, kiss1, and cyp19a1b expression was noted after 8 d at 50 nM EE2. Standard length at the end of the exposure phase was significantly lower in larvae exposed to 50 nM EE2 than in control; however, this effect was no longer observed after the depuration phase. The upregulation of gnrh2, kiss1, and cyp19a1b expression levels was found in conjunction with elevation in locomotor activity and anxiety-like behaviors in larvae. Behavioral alterations were still detected at the end of the depuration phase. Evidence indicates that the long-lasting effects of EE2 on behavior might impact normal development and subsequent fitness of exposed fish.

Effects of 17α-Ethinylestradiol (EE2) exposure during early life development on the gonadotropic axis ontogenesis of the European sea bass, Dicentrarchus labrax

Exposure of young organisms to oestrogenic endocrine disrupting chemicals (EDCs) can elicit adverse effects, particularly on the reproductive function. In fish, as in other vertebrates, reproduction is controlled by the neuroendocrine gonadotropic axis, whose components are mainly regulated by sex steroids and may then be targets for EDCs.In the present study, we investigated the effects of a xenoestrogen exposure on the ontogenesis of the gonadotropic axis in European sea bass. After exposure of hatching larvae for 8 days to 17α-ethinylestradiol (EE2) (0.5 nM and 50 nM), gene expression for kisspeptins (kiss1, kiss2), gonadotropin-releasing hormones (gnrh1, gnrh2, gnrh3), gonadotropin beta subunits (lhβ and fshβ) and brain type aromatase (cyp19a1b) were measured using quantitative real-time PCR. Our results demonstrate that EE2 strongly stimulated the expression of brain type aromatase (cyp19a1b) in sea bass larvae. In addition, EE2 exposure also affected the mRNA levels of kiss1, gnrh1 and gnrh3 by inducing a downregulation of these genes during the early developmental stages, while no effect was seen in gnrh2, lhβ and fshβ. These results reinforce the idea that the larval development is a sensitive critical period in regard to endocrine disruption and that the gonadotropic axis in the developing sea bass is sensitive to xenoestrogen exposure.

Effects of 17α-ethinylestradiol on sex ratio, gonadal histology and perianal hyperpigmentation of Cnesterodon decemmaculatus (Pisces, Poeciliidae) during a full-lifecycle exposure

The effects of 17α-ethinylestradiol (EE2) on sex ratio, gonopodium morphology, and gonadal histology of C. decemmaculatus were assessed by a full-lifecycle exposure experiment. Newborn fish were waterborne exposed to 30, 100, and 300 ng EE2/L for 90 d, using 50 fish per treatment. Additionally, in December of 2016, a field survey was conducted on a C. decemmaculatus population inhabiting the Girado Creek downstream of the Chascomus city wastewater effluent discharge. After 90 d of exposure, EE2 was able to histologically skew the sex ratio toward females and inhibit the full gonopodium development since the lowest tested concentration (LOEC = 30 ng/L). At higher concentrations, EE2 was toxic, inducing mortality in a concentration-dependent fashion (90 d-LC50 = 109.9 ng/L) and altering the gonadal histoarchitecture, causing neither testes nor ovaries discernible histologically (LOEC = 100 ng/L). In addition, a novel response, perianal hyperpigmentation, was discovered been induced by the EE2 exposure in a concentration-dependent fashion (90 d-EC50 = 39.3 ng/L). A higher proportion of females and perianal hyperpigmentation were observed in wild fish collected from the Girado Creek. The major reached conclusions are: i) EE2 induce different effects on the sexual traits of C. decemmaculatus when exposed from early-life or adult stages. ii) The most sensitive effects observed in the laboratory occur in a creek receiving wastewater effluent. iii) The perianal hyperpigmentation comes-up as a promising biomarker of exposure to estrogenic compounds.

Use of fitness-related behavioral endpoints to assess the effects of 17α-ethinylestradiol on a brackish water population of common mummichog, Fundulus heteroclitus

Endocrine-disrupting chemicals like the estrogen mimic 17α-ethinylestradiol (EE2) are released into aquatic environments from various sources and can have pronounced effects on organisms and the health of the ecosystem. Exposed species experience morphological changes, but there is little research on behavioral alterations, especially in marine organisms. This study focuses on the mummichog, Fundulus heteroclitus, an estuarine species that is a common subject of ecotoxicology research. Mummichog were exposed to different amounts of EE2 (0 ng/L, 10 ng/L, and 100 ng/L) and their behavior was examined in fitness-related assays (Empty Tank, Novel Environment, Shoaling, Foraging) once per week for 4 weeks. Exposure was found to affect behavior, especially in the foraging and shoaling contexts. The higher dose had the greatest effects on behavior, such as increasing the amount of time individuals took to find food in the Foraging assay. Both doses impacted activity levels in the Shoaling assay and eating in the Foraging assay. Females were less bold than males overall, although EE2 exposure was not found to have a significant sex-specific effect on behavior. Exposure altered fitness-related behaviors and thus may generate evolutionary consequences. This study stresses the importance of examining marine species in addition to freshwater species in ecotoxicology studies and reinforces the utility of behavior as a useful and sensitive endpoint. Additionally, it adds to our understanding of behavior within this species in general.

Effects of 17α-ethinylestradiol on embryo survival, hatchability and larval deformities in African catfish, Clarias gariepinus

Effects of 17α-ethinylestradiol on embryo survival, hatchability and larval deformities in African catfish, Clarias gariepinus

Differences in Reproductive Behavior between Spawning and Non-Spawning Zebrafish Pairs and the Effects of 17α-Ethinylestradiol (EE2).

Reproductive success manifested by spawning and fertilization, in most fish, depends partly on an appropriate courtship behavior by both sexes. The zebrafish reproductive behavior can be resolved in some of its constituent elements by a computerized vision system and described in unbiased quantitative terms. Pairs of adult male and female zebrafish were monitored with automatic video tracking at 16 Hz for 45 min in a tank with a spawning area in one corner. Subsequently, spawning, if any, was registered and the swimming behavior and mutual interactions of the two fish were quantified. Further, temporal and frequency distributions of average velocity and turning rate were produced. It is demonstrated that the courtship behavior in spawning pairs differs markedly from non-spawning pairs with differences in both male and female behavior. EE2 (17α-ethinylestradiol), a contraceptive hormone found in aquatic environments, has only a slight effect on these behavior differences between spawning and non-spawning pairs.

The role of microRNA‐27a/b and microRNA‐494 in estrogen‐mediated downregulation of tissue factor pathway inhibitor α

Essentials Estrogens are known to influence the expression of microRNAs in breast cancer cells. We looked at microRNAs in estrogenic regulation of tissue factor pathway inhibitor α (TFPIα). Estrogen upregulated microRNA-27a/b and microRNA-494 through the estrogen receptor α. MicroRNA-27a/b and microRNA-494 are partly involved in estrogenic downregulation of TFPIα. Background Tissue factor pathway inhibitor (TFPI) has been linked to breast cancer pathogenesis. We have recently reported TFPI mRNA levels to be downregulated by estrogens in a breast cancer cell line (MCF7) through the estrogen receptor α (ERα). Accumulating evidence also indicates that activation of ERα signaling by estrogens may modulate the expression of target genes indirectly through microRNAs (miRNAs). Objectives To examine if miRNAs are involved in the estrogenic downregulation of TFPIα. Methods Computational analysis of the TFPI 3'-untranslated region (UTR) identified potential binding sites for miR-19a/b, miR-27a/b, miR-494, and miR-24. Transient overexpression or inhibition of the respective miRNAs was achieved by transfection of miRNA mimics or inhibitors. Direct targeting of TFPI 3'-UTR by miR-27a/b and miR-494 was determined by luciferase reporter assay in HEK293T cells. Effects of 17α-ethinylestradiol (EE2) and fulvestrant on relative miR-27a/b, miR-494, and TFPI mRNA levels in MCF7 cells were determined by qRT-PCR and secreted TFPIα protein by ELISA. Transient knockdown of ERα was achieved by siRNA transfection. Results EE2 treatment lead to a significant increase in miR-19a, miR-27a/b, miR-494, and miR-24 mRNA levels in MCF7 cells through ERα. miR-27a/b and miR-494 mimics lead to reduced TFPI mRNA and protein levels. Luciferase assay showed direct targeting of miR-27a/b and miR-494 on TFPI mRNA. Impaired estrogen-mediated downregulation of TFPI mRNA was detected in anti-miR-27a/b and anti-miR-494 transfected cells. Conclusions Our results provide evidence that miR-27a/b and miR-494 regulate TFPIα expression and suggest a possible role of these miRNAs in the estrogen-mediated downregulation of TFPIα.

Effects of 17α-ethinylestradiol at different water temperatures on zebrafish sex differentiation and gonad development

In the current climate change scenario, studies combining effects of water contaminants with environmental parameters, such as temperature, are essential to predict potentially harmful impacts on aquatic organisms. In zebrafish (Danio rerio), sex determination seems to have a polygenic genetic basis, which can be secondarily influenced by environmental factors, such as temperature and endocrine disrupting chemicals (EDCs).The present study aimed to evaluate the effects of the EDC 17α-ethinylestradiol (EE2), a potent synthetic estrogen, on zebrafish sex differentiation and gonad development at different water temperatures. Therefore, zebrafish raised at three distinct water temperatures (23, 28 or 33±0.5°C), were exposed to 4ng/L of EE2, from 2hours to 60days post-fertilization (dpf). Subsequently, a quantitative (stereological) assessment of zebrafish gonads was performed, at 35 and 60dpf, to identify alterations on gonadal development and differentiation. The results show that low temperature delayed general growth of zebrafish, as well as gonad differentiation and maturation, while high temperature induced an opposite effect. Moreover, sex ratio was skewed toward males when zebrafish were exposed to the high temperature. In general, EE2 exposure promoted gonad maturation in both genders, independently of the temperature. However, at the high temperature condition, exposure to EE2 induced a delay in the male gonad development, with some individuals still showing differentiating gonads at 60dpf.The findings of this study support the notion that zebrafish has a genetic sex determination mechanism highly sensitive to environmental factors and show that it is essential to study the effects of water contaminants at different climate scenarios in order to understand potential future impacts on organisms.

Effect of 17α-Ethinylestradiol on the Time Needed for Males and Females of Gammarus tigrinus Sexton, 1939 to Re-couple

Effect of 17α-Ethinylestradiol on the Time Needed for Males and Females of Gammarus tigrinus Sexton, 1939 to Re-couple

Timescale effects of 17α-ethinylestradiol on behavioral consistency in male threespine stickleback

While the effects of 17α-ethinylestradiol (EE2) on male-typical behaviors are well studied, much less is known about the timing of these effects or the context in which these effects occur as most studies assay behavior at a single time point or in a single context. Additionally, exposure may affect behavior at levels beyond overall responsiveness, such as by altering behavioral consistency over time. Male threespine stickleback (Gasterosteus aculeatus) experienced three different contexts (single female, single male, paired female-male) over the course of 8 days, with an experimental group of males receiving EE2 after the first day. Exposure to EE2 disrupted responsiveness, behavioral consistency, and behavioral variation in all three social contexts. The timescale over which alterations in behavior occurred differed based on whether the conspecific was presented singly or paired with an opposite sex conspecific, stressing the importance of examining the effects of contaminants in multiple contexts.

DNA methylation in the 5′ flanking region of cytochrome P450 17 in adult rare minnow Gobiocypris rarus — Tissue difference and effects of 17α-ethinylestradiol and 17α-methyltestoterone exposures

Cytochrome P450 17 (CYP17) plays a vital role in hormone production in the body. In our previous study, mRNA expression of cyp17a1 was regulated by endocrine disrupting chemicals in rare minnow Gobiocypris rarus. However, the mechanism underlying the regulation is unclear. In the present study, we aim to explore whether the differential expression of cyp17a1 in distinct tissues and the modulation of its expression upon 17α-ethinylestradiol (EE2) and 17α-methyltestoterone (MT) are related to the DNA methylation status in G. rarus. The 732-bp fragment of 5′ flanking region of cyp17a1 gene was isolated in G. rarus. The bisulfite sequencing PCR result showed that DNA methylation levels in 5′ flanking of cyp17a1 in the gonads were significantly lower than those in the brains, which is negatively related to its mRNA expression in the 2 tissues in the previous study. The 7-day EE2 exposure of 25ng/L caused a significant increase of methylation levels of cyp17a1 gene and a significant decrease of its transcript in testis. While 100ng/L MT exposure for 7days caused a significant decrease of methylation levels of cyp17a1 gene and a significant increase of its transcript in the ovary. The present findings indicate that the methylation status of cyp17a1 gene is negatively correlated with its mRNA expression in response to EE2 and MT in G. rarus. We hypothesize that the regulation of cyp17a1 expression by EE2 and MT might attribute to the change of its DNA methylation status in G. rarus.

Effects of 17α-ethinylestradiol on individual life-history parameters and estimated population growth rates of the freshwater gastropods Radix balthica and Bithynia tentaculata

Studies of aquatic environments exposed to 17α-ethinylestradiol (EE2) have demonstrated detrimental effects on fish communities. However, much less is known about effects on macro-invertebrates and especially how long-term exposure may affect critical life stages and ultimately population dynamics. We studied the effects of EE2 on relevant endpoints for population growth in two common freshwater gastropods, Radix balthica and Bithynia tentaculata, that differ in reproductive, foraging and anti-predator strategies and endocrine systems. We quantified critical life-history parameters (mortality, somatic growth rate, days to and size at first reproduction, egg production and hatching success) in a concentration-response, life cycle experiment. The two species responded to EE2 exposure in different ways, B. tentaculata showing a significantly lower somatic growth rate and R. balthica a higher somatic growth rate. However, the magnitudes of the effects were small and EE2 exposure did not have any significant effect on estimated population growth rates for the two snail species. The significant effects of EE2 on individual endpoints, but not on population growth rate for both species, emphasise the importance of evaluating higher level effects from long-term exposure studies.

Insulin-like growth factor-3 (IGF-3) in male and female gonads of the tilapia: Development and regulation of gene expression by growth hormone (GH) and 17α-ethinylestradiol (EE2)

Recently, in addition to IGF-1 and IGF-2 the existence of a third form of IGF, termed IGF-3, limited to fishes, to be present only in the gonads and encoded by a separate gene has been reported. However, no further data have been presented on IGF-3. The present study on tilapia ( Oreochromis niloticus) uses quantitative real-time PCR specific for tilapia IGF-1 and IGF-3. The organ distribution of IGF-3 mRNA in adult fish and the early ontogeny of IGF-3 in male and female gonads were studied. The potential sensitivity of IGF-3 to GH was revealed by intraperitoneal injections of bream GH using IGF-1 as control gene. The effects of 17α-ethinylestradiol (EE2) exerted after feeding of high EE2 doses and exposure to low environmentally relevant EE2 doses on IGF-3 expression in testis and ovary during early development were determined. Low IGF-3 mRNA expression levels were detected in most organs studied, with the highest extra-gonadal amount in the pituitary. During development, the IGF-3 gene was significantly upregulated in male but downregulated in female gonad. Injections of GH elevated IGF-1 mRNA in male and female liver and ovary. IGF-3 did not respond to GH treatment neither in ovary nor in testis. Both EE2 treatments resulted in significant downregulations of IGF-3 mRNA in testis while ovarian IGF-3 mRNA did not respond. Thus, IGF-3 may be involved in reproduction of fishes most likely in the male gonad only. Whether IGF-3 also has some physiological significance in ovary or other organs should be the topic of further studies.

Effect of 17α-ethinyl estradiol on active phase rapid eye movement sleep microarchitecture

Estrogen treatment decreases active phase rapid eye movement (REM) sleep in ovariectomized rats. Here we explored further the effect of 17α-ethinyl estradiol (17α-EE) on active phase REM sleep in ovariectomized rats by analyzing spectral properties and the number and length of REM sleep bouts. The greatest suppression of REM sleep occurred on day 4 of 17α-EE treatment, was due to decreases in bout length, and was accompanied by decreased EEG theta power. These results further elucidate 17α-EE's effects on REM sleep and provide greater understanding of the mechanisms by which estrogens alter sleep–wakefulness patterns.

Effects of 17α-ethinylestradiol on sexual development of the amphipod Hyalella azteca

The effects of the synthetic estrogen 17 α-ethinylestradiol (EE) on sexual development of the freshwater amphipod Hyalella azteca was investigated. Organisms were exposed in a multigeneration experiment to EE concentrations ranging from 0.1 to 10 μg/L and the development of both external and internal sexual characteristics were studied. Second-generation male H. azteca exposed from gametogenesis until adulthood to 0.1 and 0.32 μg EE/L developed significantly smaller second gnathopods. The sex ratio of the populations exposed to EE for more than two generations tended, although not statistically significantly, to be in favor of females. Histological aberrations of the reproductive tract, i.e., indications of hermaphroditism, disturbed maturation of the germ cells, and disturbed spermatogenesis, of post-F1-generation males were observed in all EE exposures. These findings provide evidence that sexual development of H. azteca is affected by exposure to sublethal concentrations of EE.

Chronic exposure to 17α-ethinylestradiol and bisphenol A-effects on development and reproduction in the freshwater invertebrate Chironomus riparius (Diptera: Chironomidae)

The effect of 17α-ethinylestradiol (EE) and bisphenol A (BPA) on development and reproduction in Chironomus riparius was determined over two generations in chronic sediment exposure assays. A number of response criteria were examined in order to identify any chemical-related effects including median emergence times (EmT50), the number and sex ratio of emerged adults, egg production and egg viability. The results showed that emergence time and percentage adult emergence were affected by EE and BPA exposure. These effects were primarily associated with the second generation of test animals, most notably in the BPA study, where the emergence of male and female adults was significantly ( P<0.05) delayed at concentrations ranging from 78 ng/l to 0.75 mg/l. At very low concentrations (1 ng/l) of EE, both the first and second generation of adults emerged significantly earlier than control animals. No effect on the percentage emergence of first generation adults was evident with either chemical or in the second generation with BPA. The number of egg-ropes produced by the first generation females varied between treatments but no dose-response pattern was evident. Although certain responses were significantly affected, results in general do not suggest that the criteria examined, although validated as indicators of general sediment toxicity, could be used to detect the oestrogenic effects of EE and BPA on C. riparius.

Effect of 17α-ethinylestradiol on the catabolism of high-density lipoprotein apolipoprotein A-I in the rat

The in vivo metabolism and tissue sites of catabolism of high-density lipoproteins (HDL), labelled specifically in the apolipoprotein (apo) A-I moiety, were studied in rats treated with 17α-ethinylestradiol (EE) for 5 days. Apo A-I was labelled either with O-(4-diazo-3-[ 125I]iodobenzoyl)sucrose, a non-degradable labelling compound; or with 131ICI. It was found that EE treatment decreases the serum cholesterol concentration to 10 mg/dl and stimulates the serum decay of apo A-I labelled HDL. The latter effect could be attributed to an increased catabolism of apo A-I labelled HDL in the liver. The increased rates of the serum decay and tissue uptake of apo A-I labelled HDL in EE-treated rats were not affected by a bolus injection of unlabelled human low-density lipoprotein (LDL), administered at the time of the injection of the labelled HDL. When the serum cholesterol concentration was raised to physiological levels by a bolus injection of unlabelled rat HDL, both the serum decay and the tissue uptake of apo A-I labelled HDL were almost completely restored to conditions encountered in control animals. In vitro binding experiments showed that liver membranes obtained from EE-treated rats demonstrated a 6-fold increased specific binding of human 125I-LDL, but virtually unchanged specific binding of rat 125I-HDL, as compared with liver membranes obtained from control rats. It is concluded that rat HDL apo A-I catabolism is hardly mediated by the apo B/E receptor induced by EE treatment.

Effect of 17α-ethinylestradiol on biliary excreation of bile acids

The effect of 17α-ethinylestradiol on biliary bile acids has been investigated. The ratio of cholate to chenodeoxycholate was diminished by the estrogen in cholestyramine-treated rats. With low doses, this effect was due to increased excretion of chenodeoxycholate. With the highest dose, the decreased ratio was due to a reduction in the levels of cholic acid. In the intermediate dosage range, both factors contributed to the decreased ratio. Prolonged treatment with 500 ωg daily of 17α-ethinylestradiol produced a reduction in the excretory rate of both bile acids in animals treated or not treated with cholestyramine.