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Effects of glyphosate on the ovarian function of pregnant mice, the secretion of hormones and the sex ratio of their fetuses
2018
Ren, Xin | Li, Ruonan | Liu, Junze | Huang, Kai | Wu, Sheng | Li, Yansen | Li, Chunmei
Glyphosate is the active ingredient of the commercial formulation Roundup®, which is used worldwide. This study aimed to investigate the toxic effects of pure glyphosate or Roundup® on pregnant mice and their fetuses during pregnancy. From gestation days (GDs) 1–19, ICR mice were orally administered distilled water, 0.5% glyphosate solution or 0.5%-glyphosate Roundup® solution. The ovaries and serum were collected at GD19. The results showed decreases in body weight gain and, ovary and liver weight in glyphosate-treated mice. Additionally, histopathological alterations in the ovary including increased atretic follicles, interstitial fibrosis and decreased mature follicles were observed in the groups treated with glyphosate. The serum concentrations of both progesterone and estrogen were markedly altered after glyphosate exposure, and there were also changes in the expression of GnRH, LHR, FSHR, 3β-HSD and Cyp19a1 genes at the hypothalamic-pituitary-ovarian axis. Furthermore, oxidative stress was observed in the treated mice, increasing the activity of T-AOC, CAT and GSH-Px, as well as the MDA content in both the serum and ovary. With regard to litters, the sex ratio was significantly altered by pure glyphosate. These results show that glyphosate is able to cause several effects on pregnant mice, such as ovarian failure, interference with hormone secretion by affecting the steroidogenesis-related gene expression, and oxidative stress. The sex ratio of litters was also influenced by prenatal exposure to pure glyphosate.
Afficher plus [+] Moins [-]Comparison of wastewater-associated contaminants in the bed sediment of Hempstead Bay, New York, before and after Hurricane Sandy
2016
Fisher, Shawn C. | Phillips, Patrick J. | Brownawell, Bruce J. | Browne, James P.
Changes in bed sediment chemistry of Hempstead Bay (HB) have been evaluated in the wake of Hurricane Sandy, which resulted in the release of billions of liters of poorly-treated sewage into tributaries and channels throughout the bay. Surficial grab samples (top 5cm) collected before and (or) after Hurricane Sandy from sixteen sites in HB were analyzed for 74 wastewater tracers and steroid hormones, and total organic carbon. Data from pre- and post-storm comparisons of the most frequently detected wastewater tracers and ratios of steroid hormone and of polycyclic aromatic hydrocarbon concentrations indicate an increased sewage signal near outfalls and downstream of where raw sewage was discharged. Median concentration of wastewater tracers decreased after the storm at sites further from outfalls. Overall, changes in sediment quality probably resulted from a combination of additional sewage inputs, sediment redistribution, and stormwater runoff in the days to weeks following Hurricane Sandy.
Afficher plus [+] Moins [-]Assessment of chemical effects on aromatase activity using the H295R cell line
2010
Higley, Eric B | Newsted, John L | Zhang, Xiaowei | Giesy, John P | Hecker, Markus
Background, aim, and scope In response to concerns about chemical substances that can alter the function of endocrine systems and may result in adverse effects on human and ecosystem health, a number of in vitro tests have been developed to identify and assess the endocrine disrupting potential of chemicals and environmental samples. One endpoint that is frequently used in in vitro models for the assessment of chemical effects on the endocrine system is the alteration of aromatase activity (AA). Aromatase is the enzyme responsible for converting androgens to estrogens. Some commonly used aromatase assays, including the human microsomal assay that is a mandatory test in US-EPA's endocrine disruptor screening program (EDSP), detect only direct effects of chemicals on aromatase activity and not indirect effects, including changes in gene expression or transcription factors. This can be a problem for chemical screening initiatives such as the EDSP because chemicals can affect aromatase both indirectly and directly. Here we compare direct, indirect, and combined measurements of AA using the H295R cell line after exposure to seven model chemicals. Furthermore, we compare the predictability of the different types of AA measurements for 17β-estradiol (E2) and testosterone (T) production in vitro. Materials and methods H295R cells were exposed to forskolin, atrazine, letrozole, prochloraz, ketoconazole, aminoglutethimide, and prometon for 48 h. Direct, indirect, and combined effects on aromatase activity were measured using a tritiated water-release assay. Direct effects on aromatase activity were assessed by exposing cells only during the conduct of the tritium-release assay. Indirect effects were measured after exposing cells for 48 h to test chemicals, and then measuring AA without further chemical addition. Combined AA was measured by exposing cells prior and during the conduction of the tritium-release assay. Estradiol and testosterone were measured by ELISA. Results and discussion Exposure to the aromatase inhibitors letrozole, prochloraz, ketoconazole, and aminoglutethimide resulted in greater indirect aromatase activity after a 48-h exposure due to presumed compensatory mechanisms involved in aromatase activity regulation. Forskolin and atrazine caused similar changes in hormone production and enzyme profiles, and both chemicals resulted in a dose-dependent increase in E2, T, and indirect AA. Neither of these two chemicals directly affected AA. For most of the chemicals, direct and combined AA and E2 were good predictors of the mechanism of action of the chemical, with regard to AA. Indirect aromatase activity was a less precise predictor of effects at the hormone level because of presumed feedback loops that made it difficult to predict the chemicals' true effects, mostly seen with the aromatase inhibitors. Further, it was found that direct and indirect AA measurements were not reliable predictors of effects on E2 for general inducers and inhibitors, respectively. Conclusions Differential modulation of AA and hormone production was observed in H295R cells after exposure to seven model chemicals, illustrating the importance of measuring multiple endpoints when describing mechanisms of action in vitro. Recommendations and perspectives For future work with the H295R, it is recommended that a combination of direct and indirect aromatase measurements is used because it was best in predicting the effects of a chemical on E2 production and its mechanism of action. Further, it was shown that direct AA measurements, which are a common way to measure AA, must be used with caution in vitro.
Afficher plus [+] Moins [-][Studies on the fine root biology of Norway spruce (Picea abies (L.) Karst.) in the field and after controlled fumigation with No2, O3 and SO2]
1989
Blaschke, H. (Muenchen Univ. (Germany, F.R.). Lehrstuhl fuer Forstbotanik)
Investigations on the hormone-balance of healthy and damaged conifers
1986
Frenzel, B. (Hohenheim Univ., Stutgart (Germany, F.R.). Botanisches Inst.) | Christmann, A.
[Feed additives]
2002
subh,A.M.
[usage of hormons and hormon activity components to improve production at ruminants and their impacts on human health]
2002
Rahmon,W.