The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform

J F Chissell - One of the best experts on this subject based on the ideXlab platform.

Yvonne Dragan - One of the best experts on this subject based on the ideXlab platform.

  • NMR-based metabonomic evaluation of livers from rats chronically treated with tamoxifen, Mestranol, and phenobarbital
    Metabolomics, 2005
    Co-Authors: Laura Schnackenberg, Richard D. Beger, Yvonne Dragan
    Abstract:

    In this study, we look at the metabolic effects of long-term dosing with tamoxifen, Mestranol or phenobarbital on the liver. Tamoxifen, Mestranol and phenobarbital have all been reported to act as promoters of hepatic tumors. While tamoxifen and Mestranol are known to have estrogenic activity, in the liver phenobarbital is a non-estrogenic compound. Aqueous and lipophilic liver extracts from control and chronically treated Fisher 344 rats were evaluated by nuclear magnetic resonance spectroscopy (NMR). In both the aqueous and lipophilic sample sets, the estrogenic action of Mestranol appears to be responsible for the clustering of these samples with those animals treated with tamoxifen. Phenobarbital does not have estrogenic activity and, therefore, clusters away from the estrogenic and control groups. In the lipophilic samples, the fatty acid peak (CH_2)_ n was higher in tamoxifen-treated rats than in control, phenobarbital- or Mestranol-treated rats. In the aqueous samples, serine and choline levels were higher in phenobarbital-treated rats than controls, which may be an indication that the folate–homocysteine metabolic pathways were altered.

Xianfu Peng - One of the best experts on this subject based on the ideXlab platform.

Laura Schnackenberg - One of the best experts on this subject based on the ideXlab platform.

  • NMR-based metabonomic evaluation of livers from rats chronically treated with tamoxifen, Mestranol, and phenobarbital
    Metabolomics, 2005
    Co-Authors: Laura Schnackenberg, Richard D. Beger, Yvonne Dragan
    Abstract:

    In this study, we look at the metabolic effects of long-term dosing with tamoxifen, Mestranol or phenobarbital on the liver. Tamoxifen, Mestranol and phenobarbital have all been reported to act as promoters of hepatic tumors. While tamoxifen and Mestranol are known to have estrogenic activity, in the liver phenobarbital is a non-estrogenic compound. Aqueous and lipophilic liver extracts from control and chronically treated Fisher 344 rats were evaluated by nuclear magnetic resonance spectroscopy (NMR). In both the aqueous and lipophilic sample sets, the estrogenic action of Mestranol appears to be responsible for the clustering of these samples with those animals treated with tamoxifen. Phenobarbital does not have estrogenic activity and, therefore, clusters away from the estrogenic and control groups. In the lipophilic samples, the fatty acid peak (CH_2)_ n was higher in tamoxifen-treated rats than in control, phenobarbital- or Mestranol-treated rats. In the aqueous samples, serine and choline levels were higher in phenobarbital-treated rats than controls, which may be an indication that the folate–homocysteine metabolic pathways were altered.

Jorg W Metzger - One of the best experts on this subject based on the ideXlab platform.

  • substances with estrogenic activity in effluents of sewage treatment plants in southwestern germany 2 biological analysis
    Environmental Toxicology and Chemistry, 2001
    Co-Authors: Peter Spengler, Wolfgang Korner, Jorg W Metzger
    Abstract:

    A gas chromatography/mass spectrometry method for the simultaneous quantitative determination of natural and synthetic estrogens (17β-estradiol, estrone, 17α-ethinylestradiol, and Mestranol), phytoestrogens (genistein and β-sitosterol), and xenoestrogens (benzyl butyl phthalate, dibutyl phthalate, bisphenol A, 4-nonylphenol [NP], 4-nonylphenoxyacetic acid [NP1EC], 4-nonyl-phenol diethoxylate [NP2EO], and α-endosulfan) in effluents of sewage treatment plants (STPs) was developed. Identification and quantification were carried out with the standard addition method using analyte-specific and, in some cases, deuterium-labeled internal standards. The effluents of 18 STPs were investigated. Apart from α-endosulfan and Mestranol, all selected substances were detected in the majority of samples. The median concentrations of steroidal estrogens were between 0.4 ng/L (17α-ethiny-lestradiol) and 1.6 ng/L (17β-estradiol). The metabolites of the nonylphenol polyethoxylates, NP, NP1EC, and NP2EO were found in concentrations ranging from the upper-ng/L-range (NP) to the lower-μg/L range (NP1EC). For all substances except Mestranol and α-endosulfan, median values were calculated and compared to the results of other investigations in Europe and the United States. Possible dependencies of measured concentrations on the geographical location, the capacity, the influent composition, and the technical fitting of the STPs are discussed.