The role of 2-methoxyestrone in estrogen action

Systems Analysis Reveals Ageing-Related Perturbations in Retinoids and Sex Hormones in Alzheimer's and Parkinson's Diseases

Neurodegenerative diseases, including Alzheimer's (AD) and Parkinson's diseases (PD), are complex heterogeneous diseases with highly variable patient responses to treatment. Due to the growing evidence for ageing-related clinical and pathological commonalities between AD and PD, these diseases have recently been studied in tandem. In this study, we analysed transcriptomic data from AD and PD patients, and stratified these patients into three subclasses with distinct gene expression and metabolic profiles. Through integrating transcriptomic data with a genome-scale metabolic model and validating our findings by network exploration and co-analysis using a zebrafish ageing model, we identified retinoids as a key ageing-related feature in all subclasses of AD and PD. We also demonstrated that the dysregulation of androgen metabolism by three different independent mechanisms is a source of heterogeneity in AD and PD. Taken together, our work highlights the need for stratification of AD/PD patients and development of personalised and precision medicine approaches based on the detailed characterisation of these subclasses.

Studies on neurosteroids. IX. Characterization of estrogens in rat brains using gas chromatography-tandem mass spectrometry

The characterization of the classical estrogens (estrone, estradiol, estriol) and guaiacol estrogens (2-hydroxyestrone 3-methyl ether, 4-hydroxyestrone 3-methyl ether) in rat brains was performed using gas chromatography-tandem mass spectrometry (GC-MS-MS). Estrogens were purified from Wistar strain rat brains by some chromatographic pre-treatments, such as solid-phase extraction, preparative thin-layer chromatography or preparative high-performance liquid chromatography. After the derivatization with O-methylhydroxylamine and/or N,O-bis(trimethylsilyl)trifluoroacetamide, estrogens were identified by comparison of their chromatographic behavior during GC-MS-MS operating in the product ion scan mode and comparison with the product ion MS spectra of an authentic sample. These evidences suggested that estrogens exist in rat brains as neurosteroids or neuroactive steroids.

Determination of catechol and guaiacol estrogens in urine by capillary gas chromatography/mass spectrometry

A gas chromatographic (GC)/mass spectrometric method for the simultaneous determination in urine of 2- and 4-hydroxyestrones and hydroxyestradiols, and their monomethyl ethers, is described. Separation of these catechol and guaiacol estrogens was achieved by derivatization into their trimethylsilyl and tert-butyldimethylsilyl ethers, followed by capillary GC on a DB-1 column. The calibration graphs were satisfactorily constructed for these estrogen metabolites by selected ion monitoring at the respective molecular ions using 2-bromoestrone and 4-hydroxyestradiol-d3 3-methyl ether as internal standards. The extraction and purification of the desired estrogens in biological fluids were effected by the combined use of Extrelut-3 and ion exchange columns. The sensitivity and reliability obtained by the newly developed method has proved to be satisfactory for the quantitation of catechol and guaiacol estrogens in human urine.

P450 enzymes of estrogen metabolism

Endogenous and exogenous estrogens undergo extensive oxidative metabolism by specific cytochrome P450 enzymes. Certain drugs and xenobiotics have been found to be potent inducers of estrogen hydroxylating enzymes with C-2 hydroxylase induction being greater than that of C-16 hydroxylase. Oxygenated estrogen metabolites have different biological activities, with C-2 metabolites having limited or no activity and C-4 and C-16 metabolites having similar potency to estradiol. Pathophysiological roles for some of the oxygenated estrogen metabolites have been proposed, e.g. 16 alpha-hydroxyestrone and 4-hydroxyestrone. These reactive estrogens are capable of damaging cellular proteins and DNA and may be carcinogenic in specific cells.

Low polarity ligands of sex hormone-binding globulin in pregnancy. Part II--Identification

Certain previously unrecognized ligands of SHBG of low polarity in pregnancy were identified. They include two weakly bound compounds: 5 alpha-pregnane-3,20-dione and progesterone; and two strongly bound substances, 2-methoxyestrone and a new steroid, estradienolone (17 beta-hydroxy-1,5-estradiene-3-one). The identification of the first three peaks was based on chromatographic elution patterns, binding characteristics and gas chromatography-mass spectrometry. The identification of the fourth peak, the new steroid, was based on similar kinds of evidence and, in addition, solubility characteristics and ultraviolet absorption spectrum.