Many studies have focused on environmental estrogen-related diseases. However, no consistent gene markers or signatures for estrogenicity have been discovered in mammals. This study investigated the estrogenic effects of 17β-estradiol on the prostate in immature male mice. Consistent U-shaped responses were seen in bodyweight, ventral prostate epithelial morphology, and miRNA expression levels. Specifically, most estradiol regulated miRNAs were downregulated at low doses of estradiol (0.2 and 2 mg·kg–1), and whose expression returned to the control level at a larger dose (200 mg·kg–1). The function of these regulated miRNAs is related to the prostate cancer and PI3K-Akt signaling pathways, which is consistent with the function of estradiol. Furthermore, the miRNA-processing machinery, Drosha, in the prostate was also regulated in a similar pattern, which could be a part of the U-shaped miRNA expression mechanism. All of these data indicate that the prostate is a reliable organ for evaluating estrogenic activity and that the typical nonmonotonic dose-response relationship could be used as a novel biomarker for estrogenicity.
Regeneration is a vital physiological process for survival of adult organisms. Bisphenol A (BPA), diethystilbestrol (DES), 17α-ethinylestradiol (EE2), and 17β-estradiol (E2) were examined for their effects on head formation in decapitated freshwater planarians (Dugesia japonica). The median lethal concentration of the test chemicals and the median inhibitory concentration for decapitated planarians and different regenerative endpoints, were determined for 3–7 d of exposure. For planarian head regeneration, the no-observed-effect level of BPA and DES was 0.05 mg L?1 and 1 mg L?1 for EE2 and E2. The effects of BPA, DES, and EE2 on asexual planarian regeneration did not correspond with the order of their estrogenic potencies, suggesting that the effects, at least partially, were due to general toxicity rather than their estrogenicity. In view of the published data on concentrations of xenoestrogens in water bodies versus the nominal levels tested here, this study suggests that the current environmental levels of BPA, DES, EE2, and E2 have no immediate adverse effects on freshwater planarian regeneration. 相似文献
Background Ecotoxicology utilizes alterations of biological parameters of organisms as biomarkers of toxic exposure or effects. In environmental monitoring, biomarkers function as sensitive indicators of chemical pollution or as early warning signal of late effects Aim The pre-requisite for using a biological parameter as biomarker is the ability to unequivocally distinguish between the natural or normal and the induced or abnormal expression of the marker. This article discusses problems in discriminating between the normal and induce state, using morphological biomarkers as an example. Results and Discussion Morphological and/or anatomical parameters are intuitively considered to be rather invariable. This article shows for the example of gonad morphology of fish that this expectation is not always correct, but that morphological markers may display pronounced baseline variability. The reasons for this variability are often not understood. This is limiting the utility and interpretation of the biomarker response, in particular when organisms are not only exposed to chemical but to multiple stressors. Outlook The problem of discriminating between natural and induced variability of biomarkers is of particular relevance in low dose exposure scenarios, when stressors other than toxic chemicals may confound the toxicant-induced changes of the biomarker status. To better handle this problem and to be able to distinguish between adaptive and adverse changes, ecotoxicology has to set out for improved understanding of the phenotypic plasticity of organisms and genotypes, 相似文献
Both the UK and Japan are densely populated islands with relatively short rivers. Therefore, both countries are likely to be highly exposed to contaminants emanating from their human populations. This review considered how effective the different sewage treatment facilities of the two countries are at removing steroid estrogens from the effluent. The methods of estrogen analysis in sewage effluent, the number and importance of different sewage treatment types, and their apparent effectiveness at removing estrogens were all considered. In both countries, the activated sludge treatment was dominant in terms of people served and water discharged. The analytical techniques used by those studying estrogen concentrations in effluents in both countries were broadly similar. Activated sludge plant (ASP) effluent in the UK typically contained around 2 ng/L estradiol (E2) and 8 ng/L estrone (E1), while Japanese ASPs typically reported E2 as below detection, and 10 ng/L E1 in their effluents. When estrogenic bioassays were used in Japan, they typically record an estrogenic potency of 10 ng/L E2 equivalents. Even taking into account ethinylestradiol (EE2) (not found in Japanese effluents), the overall estrogenicity of British sewage effluents would appear to be the same as that of Japanese sewage effluents (around 10 ng/L E2 equivalents). This suggests that the ASPs serving the large urban communities in Japan and the UK would have effluent of similar estrogenic potencies. Less information is available about the more numerous biological (trickling) filter plants (BFP) in the UK and oxygen ditches (OD) in Japan which tend to serve smaller, more rural communities. The available data would suggest that the BFPs are significantly less efficient than the ODs at removing E1. This would suggest that in similar circumstances, British headwaters (where this sewage treatment plant (STP) type is often found) might be more at risk from endocrine disruption than their Japanese counterparts. Overall, the apparently higher incidence of endocrine disruption in British wild fish than in Japanese wild fish cannot be attributed to differences in the efficiency of their respective STPs. 相似文献
A number of xenobiotic organic substances are known which, in cases of prenatal exposition, may produce an estrogenic effect leading subsequently to serious reproductive disorders in the male progeny. Damage of this kind which is seen to occur in wildlife populations leads to the assumption that environmental chemicals exerting such estrogenic effects may be responsible for these disorders. Listed here are environmental chemicals which are known to date to exert an estrogenic effect. The article provides a review of papers and hypotheses on the estrogenic effects of xenobiotic substances. This is followed by a discussion concerning the significance of chemical estrogenicity on environmental and chemical policies as well as on the possibilities and limitations of test systems for the verification of estrogenicity. 相似文献
Cadmium (Cd2+), a known carcinogen, mimics the effects of estrogen in the uterus and mammary gland suggesting its possible involvement in the development and progression of breast cancer. This lab showed through analysis of a small set of archival human diagnostic specimens that the third isoform of the classic Cd2+ binding protein metallothionein (MT-3) is not expressed in normal breast tissue, but is expressed in some breast cancers and that expression tends to correlate with a poor disease outcome. The goals of this study were to verify that overexpression of MT-3 in a large set of archival human diagnostic specimens tends to correlate with poor disease outcome and define the mechanism of MT-3 gene regulation in the normal breast epithelial cell. The results showed that MT-3 was expressed in approximately 90% of all breast cancers and was absent in normal breast epithelium. The lack of MT-3 staining in some cancers correlated with a favorable patient outcome. High frequency of MT-3 staining was also found for in situ breast cancer suggesting that MT-3 might be an early biomarker for breast cancer. The study also demonstrated that the MCF-10A cell line, an immortalized, non-tumorigenic model of human breast epithelial cells, displayed no basal expression of MT-3, nor was it induced by Cd2+. Treatment of the MCF-10A cells with the demethylation agent, 5-aza-2′-deoxycytidine, or the histone deacetylase inhibitor, MS-275, restored MT-3 mRNA expression. It was also shown that the MT-3 metal regulatory elements are potentially active binders of protein factors following treatment with these inhibitors suggesting that MT-3 expression may be subject to epigenetic regulation. 相似文献
The expression of protogyny often differs among populations of a single species. The humbug damselfish, Dascyllus aruanus (Linnaeus), typically lives in spatially discrete groups of several individuals around live coral colonies and has been reported to be protogynous. The size and sexual composition of groups of this species, however, vary with the size of the coral patch or the degree of coral cover. The present study examined gonadal development and sexual pattern in a population of D. aruanus living in continuous coral-cover habitat. Fish were collected in Tumon Bay, Guam (13°31′N; 144°47′E), during a 2-week period in July and August 1996. Reflecting their distributions, small fish (n=54) were collected at depths of 1–2 m over continuous Porites spp. patches, and large fish (n=56) were collected at depths of 2–3 m over a continuous Acropora spp. patch. Gonadal development was examined histologically. Gonads of D. aruanus first developed an ovarian lumen and primary-growth stage oocytes. From this ovarian state or from more developed ovaries with cortical-alveolus stage oocytes, some gonads developed into testes through degeneration of oocytes and development of spermatogenic tissue. Developing spermatogenic tissue only occurred in gonads having pre-cortical alveolus stage oocytes, and the size of individuals with gonads of this type overlapped mainly with the size range of individuals with gonads containing only pre-vitellogenic oocytes (i.e. immature females). This suggested that functional female-to-male sex change was rare or absent in this population of D. aruanus. Moreover, the different habitat distributions of small and large fish suggest that sex determination in immature fish occurs in the absence of adults. 相似文献
A preliminary investigation of the solution phase behaviour of the biomarker compound 1-aminopropan-2-one (APR) using NMR
spectroscopy was carried out. This was achieved, in part, by synthesis of APR with13C-enrichment in the methylene position. In this paper, we report that this biomarker undergoes H/D exchange with D2O, probably via an enol intermediate. In addition, use of13C-enriched APR enabled its detection by13C NMR spectroscopy at environmentally relevant concentrations. 相似文献
