Purification of urine for quantification of the complete estrogen profile

Urinary 2- to 16α-hydroxyestrone ratio did not change with cruciferous vegetable intake in premenopausal women

The mass ratio of urinary 2-hydroxyestrone to 16-α-hydroxyestrone (2:16) is hypothesized as a biomarker of breast cancer risk in premenopausal women, with higher ratios being theoretically protective. Cruciferous vegetable intake has been associated with higher urinary 2:16 in some studies. We investigated whether a whole-food supplement made from dried Brussels sprouts and kale would increase urinary 2:16 in comparison with placebo or cruciferous vegetables in women. This randomized, parallel arm, placebo-controlled, partly blinded study included 78 healthy premenopausal women (38-50 y) with screening urinary 2:16 ≤3.0. Subjects received either six capsules containing 550 mg dried Brussels sprouts and kale per capsule, 40 g daily alternating broccoli or Brussels sprouts, or placebo for eight weeks. Urinary 2:16 and creatinine were measured at baseline, four, and eight weeks. Intent-to-treat repeated measures-ANOVA with multiple imputation (n=100) for missing values identified no treatment effect (P=0.9) or treatment-by-time interaction (P=0.6); however, a significant time effect was noted (P=0.02). Per-protocol analyses including complete cases found no treatment effect (P=1) or treatment-by-time interaction (P=0.6); however, the significant time effect remained (P=0.03). Restricting analysis to subjects with >80% compliance maintained the time effect (P=0.02). Using Pearson correlations, android-pattern and android:gynoid fat were predictive of change (P≤0.05). In conclusion, neither cruciferous supplements nor an added vegetable serving altered urinary 2:16 in premenopausal women with eight weeks treatment. This ratio did vary with time, which is important for designing future trials.

Markers of Local and Systemic Estrogen Metabolism in Endometriosis

Estrogen metabolites (EMs) can work independently from their parent hormones. We hypothesize that in endometriosis, estrogen is metabolized preferentially along hormonally active pathways. We recruited 62 women with endometriosis (proven laparoscopically and histologically) and 52 control women (normal findings with laparoscopy) among patients undergoing surgery for pelvic pain and/or infertility during the proliferative phase of the menstrual cycle. Urinary samples were collected preoperatively. Biopsies from eutopic endometrium of control women and women with endometriosis were collected during surgery. EMs in urine and endometrial tissues were extracted and determined using Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS/MS). These included: 2-hydroxyestrone (2OHE1), 16-α hydroxyestrone (16α-OHE1), 2OHE1/16α-OHE1 ratio, 4-hydroxyestrone (4OHE1), 2-hydroxyestradiol (2OHE2), and 4-hydroxyestradiol (4OHE2). Eutopic endometrium of endometriosis patients, as compared to control endometrium, contained significantly higher level of 4OHE1 (0.03 (IQR: 0.03-0.265) versus 0.03 (IQR: 0.03-0.03) μg/g, respectively, P = 0.005), 2-OHE2 (0.241 (IQR: 0.1-0.960) versus 0.1 (IQR: 0.1-0.1) μg/g, respectively, P < 0.001), and 4-OHE2 (0.225 (IQR: 0.22-1.29) versus 0.0.2 (IQR: 0.2-0.2) μg/g, respectively, P < 0.001). Only 2OHE1 showed higher concentration in urine of women with endometriosis than controls (9.9 (IQR: 3.64-14.88) versus 4.5 (IQR: 1.37-17.00) μg/mg creatinine, respectively, P = 0.042). Eutopic endometrium of women with endometriosis metabolizes estrogen preferentially to the biologically active 2OHE2, and potentially genotoxic 4OHE1 and 4OHE2 metabolites. This contributes to further understanding of endometriosis etiology, its link to ovarian cancer, and could help identifying an endometrial biomarker of the disease.

Stability of 15 Estrogens and Estrogen Metabolites in Urine Samples under Processing and Storage Conditions Typically Used in Epidemiologic Studies

Background

In preparation for large-scale epidemiologic studies of the role of estrogen metabolism in the etiology of breast and other cancers, we examined the stability of estrogens and estrogen metabolites (EM) in urine during processing and storage protocols.

Methods

Fifteen EM were measured using liquid chromatography–tandem mass spectrometry (LC-MS/MS) in first morning urines from 3 premenopausal women. Linear regression was used to model log EM concentrations for each woman, with and without adding ascorbic acid (0.1% w/v), during storage at 4°C (7–8 time points, up to 48 hours), during long-term storage at –80°C (10 time points, up to 1 year), and by freeze-thaw cycles (up to 3).

Results

Without ascorbic acid, concentrations (pmol/mL) of nearly all EM changed <1% per 24 hours of storage at 4°C, and <1% during storage at –80°C for 1 year; similarly, thawing and refreezing samples 3 times was not consistently associated with losses for any EM. Ascorbic acid had no clear beneficial effect on EM stability in these experiments.

Conclusions

Given the large inter-individual variability in urinary EM concentrations, changes of the magnitude observed here are unlikely to cause substantial misclassification. Furthermore, processing and storage conditions studied here are adequate for use in epidemiologic studies.

4-Phenoxyphenol-Functionalized Reduced Graphene Oxide Nanosheets: A Metal-Free Fenton-Like Catalyst for Pollutant Destruction

Metal-containing Fenton catalysts have been widely investigated. Here, we report for the first time a highly effective stable metal-free Fenton-like catalyst with dual reaction centers consisting of 4-phenoxyphenol-functionalized reduced graphene oxide nanosheets (POP-rGO NSs) prepared through surface complexation and copolymerization. Experimental and theoretical studies verified that dual reaction centers are formed on the C-O-C bridge of POP-rGO NSs. The electron-rich center around O is responsible for the efficient reduction of H₂O₂ to ^•OH, while the electron-poor center around C captures electrons from the adsorbed pollutants and diverts them to the electron-rich area via the C-O-C bridge. By these processes, pollutants are degraded and mineralized quickly in a wide pH range, and a higher H₂O₂ utilization efficiency is achieved. Our findings address the problems of the classical Fenton reaction and are useful for the development of efficient Fenton-like catalysts using organic polymers for different fields.

Infection with Opisthorchis felineus induces intraepithelial neoplasia of the biliary tract in a rodent model

The liver fluke Opisthorchis felineus is a member of the triad of epidemiologically relevant species of the trematode family Opisthorchiidae, and the causative agent of opisthorchiasis felinea over an extensive range that spans regions of Eurasia. The International Agency for Research on Cancer classifies the infection with the liver flukes Opisthorchis viverrini and Clonorchis sinensis as group 1 agents and a major risk factor for cholangiocarcinoma. However, the carcinogenic potential of the infection with O. felineus is less clear. Here, we present findings that support the inclusion of O. felineus in the Group 1 list of biological carcinogens. Two discrete lines of evidence support the notion that infection with this liver fluke is carcinogenic. First, novel oxysterol-like metabolites detected by liquid chromatography-mass spectroscopy in the egg and adult developmental stages of O. felineus, and in bile, sera, and urine of liver fluke-infected hamsters exhibited marked similarity to oxysterol-like molecules known from O. viverrini. Numerous oxysterols and related DNA-adducts detected in the liver fluke eggs and in bile from infected hamsters suggested that infection-associated oxysterols induced chromosomal lesions in host cells. Second, histological analysis of liver sections from hamsters infected with O. felineus confirmed portal area enlargement, inflammation with severe periductal fibrosis and changes in the epithelium of the biliary tract characterized as biliary intraepithelial neoplasia, BilIN. The consonance of these biochemical and histopathological changes revealed that O. felineus infection in this rodent model induced precancerous lesions conducive to malignancy.

Estrogen-like metabolites and DNA-adducts in urogenital schistosomiasis-associated bladder cancer

An estrogen-DNA adduct mediated pathway may be involved in the pathogenesis of the squamous cell carcinoma of the bladder associated with infection with the blood fluke Schistosoma haematobium. Extracts from developmental stages of S. haematobium, including eggs, induce tumor-like phenotypes in cultured cells. In addition, estrogen-derived, reactive metabolites occur in this pathogen and in sera of infected persons. Liquid chromatography-mass spectrometry analysis was performed on urine from 40 Angolans diagnosed with urogenital schistosomiasis (UGS), half of who also presented UGS-associated squamous cell carcinoma and/or urothelial cell carcinoma. The analysis revealed numerous estrogen-like metabolites, including seven specifically identified in UGS cases, but not reported in the database of metabolites in urine of healthy humans. These schistosome infection-associated metabolites included catechol estrogen quinones (CEQ) and CEQ-DNA-adducts, two of which had been identified previously in S. haematobium. In addition, novel metabolites derived directly from 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodG) were identified in urine of all 40 cases of UGS. These metabolites can be expected to provide deeper insights into the carcinogenesis UGS-induced bladder cancer, and as biomarkers for diagnosis and/or prognosis of this neglected tropical disease-linked cancer.

Profiling oestrogens and testosterone in human urine by stable isotope dilution/benchtop gas chromatography-mass spectrometry

Oestrogens, such as oestrone (E(1)), 17β-oestradiol (E(2)), oestriol (E(3)) and their biologically active metabolites 2-methoxyoestrone (2-MeOE(1)), 2-hydroxyoestradiol (2-OHE(2)) 16-ketooestradiol (16-OE(2)), 16-epioestriol (16-epiE(3)), as well as testosterone (T) play an important role in physiological and pathological developmental processes during human development. We therefore aimed at developing an isotope dilution/bench top gas chromatography-mass spectrometry (ID/GC-MS) method, based on benchtop GC-MS, for the simultaneous determination ('profiling') of the above analytes in children. The method consisted of equilibration of urine (5 ml) with a cocktail containing stable isotope-labelled analogues of the analytes as internal standards ([2,4-(2)H(2)]E(1), [2,4,16,16-(2)H(4)]E(2), [2,4,17-(2)H(3)]E(3), [16,16,17-(2)H(3)]T, [1,4,16,16-(2)H(4)]2-MeOE(1), [1,4,16,16,17-(2)H(5)]2-OHE(2), [2,4,15,15,17-(2)H(5)]16-OE(2) and [2,4-(2)H(2)]16-epiE(3)). Then, solid-phase extraction (C(18) cartridges), enzymatic hydrolysis (sulphatase from Helix pomatia (type H-1)), re-extraction, purification by anion exchange chromatography and derivatisation to trimethylsilyl ethers followed. The samples were analysed by GC-MS (Agilent GC 6890N/5975MSD; fused silica capillary column 25 m × 0.2 mm i.d., film 0.10 μm). Calibration plots were linear and showed excellent reproducibility with coefficients of determination (r(2)) between 0.999 and 1.000. Intra- and inter-assay coefficients of variation (CV) were <2.21% for all quantified metabolites. Sensitivity was highest for 2-OHE(2) (0.25 pg per absolute injection: signal-to-noise ratio (S/N)=3) and lowest for 16-epiE(3) (2 pg per absolute injection: S/N=2.6), translating into corresponding urine sample analyte concentrations of 0.025 ng ml(-1) and 0.2 ng ml(-1), respectively. Accuracy - determined in a two-level spike experiment - showed relative errors ranging between 0.15% for 16-OE(2) and 11.63% for 2-OHE(2). Chromatography showed clear peak shapes for the components analysed. In summary, we describe a practical, sensitive and specific ID/GC-MS assay capable of profiling the above-mentioned steroids in human urine from childhood onwards.

A new approach to measuring estrogen exposure and metabolism in epidemiologic studies

Endogenous estrogen plays an integral role in the etiology of breast and endometrial cancer, and conceivably ovarian cancer. However, the underlying mechanisms and the importance of patterns of estrogen metabolism and specific estrogen metabolites have not been adequately explored. Long-standing hypotheses, derived from laboratory experiments, have not been tested in epidemiologic research because of the lack of robust, rapid, accurate measurement techniques appropriate for large-scale studies. We have developed a stable isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS(2)) method that can measure concurrently all 15 estrogens and estrogen metabolites (EM) in urine and serum with high sensitivity (level of detection=2.5-3.0fmol EM/mL serum), specificity, accuracy, and precision [laboratory coefficients of variation (CV's) < or =5% for nearly all EM]. The assay requires only extraction, a single chemical derivatization, and less than 0.5mL of serum or urine. By incorporating enzymatic hydrolysis, the assay measures total (glucuronidated+sulfated+unconjugated) EM. If the hydrolysis step is omitted, the assay measures unconjugated EM. Interindividual differences in urinary EM concentrations (pg/mL creatinine), which reflect total EM production, were consistently large, with a range of 10-100-fold for nearly all EM in premenopausal and postmenopausal women and men. Correlational analyses indicated that urinary estrone and estradiol, the most commonly measured EM, do not accurately represent levels of total urinary EM or of the other EM. In serum, all 15 EM were detected as conjugates, but only 5 were detected in unconjugated form. When we compared our assay methods with indirect radioimmunoassays for estrone, estradiol, and estriol and enzyme-linked immunosorbent assays for 2-hydroxyestrone and 16alpha-hydroxyestrone, ranking of individuals agreed well for premenopausal women [Spearman r (r(s))=0.8-0.9], but only moderately for postmenopausal women (r(s)=0.4-0.8). Our absolute readings were consistently lower, especially at the low concentrations characteristic of postmenopausal women, possibly because of improved specificity. We are currently applying our EM measurement techniques in several epidemiologic studies of premenopausal and postmenopausal breast cancer.

Fate and removal of estrogens in municipal wastewater

Natural and synthetic estrogens are some of the most potent endocrine disrupting compounds found in municipal wastewater. Much research has been conducted on the source and fate of estrogens in wastewater treatment plants. Sorption and biodegradation are the primary removal mechanisms for estrogens in activated sludge systems, which are widely used biological treatment techniques for municipal wastewater treatment. However, when removal of estrogens in a wastewater treatment plant is incomplete, these compounds enter the environment through wastewater discharges or waste activated sludge at concentrations that can cause endocrine-reproductive system alterations in birds, reptiles and mammals. Therefore, studies have also focused on potential advanced treatment technologies with the aim of removing the compounds before discharging wastewater effluent or disposing waste sludge. This review discusses the physiological effects of these estrogens and the degree of problems estrogens pose as they enter the wastewater stream. Thereafter, this review also analyzes their fate in wastewater treatment systems and how they may reach drinking water sources. Furthermore, this review includes a discussion on various treatment technologies being investigated and future research trends for this pressing environmental issue.

Observations on the estrogenic activity and concentration of 17beta-estradiol in the discharges of 12 wastewater treatment plants in southern australia

There is very little information on the overall level of estrogenic activity, or concentrations of specific hormonal compounds in wastewater treatment plant (WWTP) discharges in Australia, compared with Europe, Japan, and North America. To partly address this, in 2004, water samples were collected as "grab" or "spot" samples from 12 WWTP facilities across southern Victoria at the point at which effluent enters the environment, either as recycled water or direct discharge to the receiving water. The WWTPs were of a variety of treatment types and served a diverse range of rural and regional municipalities. For instance, of the 12 WWTPs, 3 served municipalities with populations greater than 100,000, 4 with populations between 20,000 and 100,000, and 5 with populations less than 5,000. The principal treatment process in six was an activated sludge system, and three were trickle-filter-based systems. The remaining plants fall into a "miscellaneous" category, each plant having a mixture of treatment processes within the overall systems. The estrogenic activity and 17beta-estradiol concentrations of the samples were assessed using a yeast-based, in vitro reporter gene assay and enzyme-linked immunosorbant assays, respectively. Most of the effluents showed estrogenic activity in the assays (hER, no response: 7.9 ng/L EEQ; mER, no response: 44.5 ng/L EEQ). There was no correlation between estrogenic response and the results of a concurrent toxicity assay, suggesting that a lack of bioassay response was related to lack of estrogenic compounds, rather than the direct toxic effect of the sample. Estradiol concentrations were for the most part in the range 2-5 ng/L, with one sample at 18 ng/L. Despite the assurance our results might provide (of minimal impact in most cases if there is significant dilution), there is still a need for further extensive on-ground reassurance research to provide data for higher-level risk assessment by industry and government agencies. In particular, more research is warranted to verify the estrogenic activity and to expand the range of specific hormone/metabolites reported in these studies. Moreover, studies are required to determine if the estrogenic activity reported in this and other recent Australian studies is sufficient to induce a physiological effect in exposed aquatic organisms, especially Australian native fish.

Sodium ascorbate improves yield of urinary steroids during hydrolysis with Helix pomatia juice

Urinary steroid profile analysis requires enzymatic hydrolysis of glucuronide and sulfate conjugates and this is achieved simultaneously using Helix pomatia juice (HPJ), but steroids with 3beta-hydroxy-5-ene structure undergo transformation and yield of 5alpha-reduced corticosteroid glucuronides is poor. We describe the use of sodium ascorbate to solve these problems and provide a basis for its mode of action. Steroid conjugates were extracted from urine, hydrolyzed in acetate buffer with HPJ and sodium ascorbate and analyzed as methyloxime-trimethylsilylether derivatives by gas chromatography-mass spectrometry. Ranges of temperature, pH and ascorbate, substrate and HPJ concentrations were compared for urine and pure standards. Activity of other antioxidants and that of bacterial cholesterol oxidase were examined. Helix pomatia enzyme preparations from different commercial sources were compared. Loss of 3beta-hydroxy-5-ene steroids was enzyme-dependant, since it required HPJ, was saturable, subject to substrate competition and heat-inactivated. Products were 3-oxo-4-ene steroids and 4,6-diene and 6-oxy derivatives of these but the latter were not formed from 3-oxo-4-ene precursors. Ascorbate, other antioxidants or oxygen exclusion diminished activity. These characteristics were shared by cholesterol oxidase. Yield of 5alpha-reduced steroids was diminished by pre-incubation of HPJ before ascorbate addition and this was reversed if ascorbate was added to the pre-incubation mixture. We conclude that transformation of 3beta-hydroxy-5-ene steroids by HPJ is due to cholesterol oxidase and is diminished by antioxidants or oxygen denial. Yield of 5alpha-reduced steroids is low due to oxidative damage of beta-glucuronidase during hydrolysis, prevented by ascorbate. These features are shared by most commercial Helix pomatia enzyme preparations tested.

A model to estimate influent and effluent concentrations of estradiol, estrone, and ethinylestradiol at sewage treatment works

To predict sewage influent and effluent concentrations of the steroid estrogens 17beta-estradiol, estrone, and 17alpha-ethinylestradiol, a review of human excretion was carried out. This included conjugation and metabolism of the natural and synthetic steroid estrogens within the body, together with quantities excreted in the urine and feces by different members of the population. This has been combined with fate and behavior information for conjugated and unconjugated estrogens in the sewage treatment system to enable sewage works influent and effluent concentration predictions to be made. The model has proved to be reasonably accurate when tested against recent measurements of these steroid estrogens in the influent and effluent of sewage treatment works. The model may be used with river dilution ratios to predict which sewage treatment works are most likely to cause the greatest endocrine disruption due to steroid estrogens.

Estimating steroid oestrogen inputs into activated sludge treatment works and observations on their removal from the effluent

A method to predict steroid oestrogen inputs into sewage works is described and tested against available data. For oestradiol (E2), 68% of the predictions were within 50% of the actual measured value, and for oestrone (E1), 52% of the estimations were within 50% of the measured value. Predictions for ethinyloestradiol (EE2), which are particularly sensitive to assumptions on the number of people taking the oral contraceptive, were less accurate. Five Italian and three Dutch activated sludge treatment works (STW) were sampled on two to three occasions for E2, E1, EE2 and E3 (E3 only in Italy) in both influent and effluent waters. High concentrations of E3 were found in the influent, as predicted, with a mean of 57 ng/1 and a mean of 10 ng/l in the effluent. Using the currently available data collected from composite samples, an average of 88% of E2 and 74% of E1 would appear to be removed by the activated sludge process.

Quantitative and qualitative determination of estrogen sulfates in human urine by liquid chromatography/tandem mass spectrometry using 96-well technology

A sensitive and robust method to determine five estrogen sulfates in human urine has been developed employing high-throughput solid-phase extraction with 96-well technology, and HPLC coupled with negative turbo ion spray tandem mass spectrometry in the selected reaction monitoring mode. The five estrogen sulfates determined include three major endogenous estrogen sulfates in the human, estrone 3-sulfate (E1-3S), estriol 3-sulfate (E3-3S), and 17 beta-estradiol 3-sulfate (E2-3S), and two biochemical synthetic estrogen sulfates, 17 beta-estradiol 17-sulfate (E2-17S) and 17 beta-estradiol 3,17-disulfate (E2-3,17S). For E2-3,17S, E3-3S, and E2-17S, external standard calibration was used for quantitation, and for the remaining two compounds, internal standard calibration using a stable isotopic labeled internal standard was employed. A total of 96 samples may be prepared with 96-well C18 extraction disk plate techniques performed by a robot within 25 min including the time for evaporation of solvent. The lower level of quantitation (LOQ) for these estrogen sulfates in human urine was determined at 0.2 ng/mL based on 100-microL aliquots of human urine using the optimum tuning parameters for each individual selected precursor ion/product ion transition. The assay was validated with a linear concentration range of 0.2-200 ng/mL, and the interassay accuracy, intraassay precision, and interassay precision do not exceed 8.6%, 12%, and 12%, respectively, by analysis of quality control samples at five concentration levels including the LOQ of 0.2 ng/mL, from four 96-well plates. The target endogenous test articles were qualitatively determined by comparing the full-scan LC/MS/MS mass spectra and retention time in test samples and reference standards. The LOQ is significantly improved compared to previous reports for the targeted compounds using LC/MS/MS. The described simple and automated sample preparation procedure recovered 91% of the target compounds. A total of 192 samples can be analyzed within 1 day (22 h). The method can measure the endogenous estrogen sulfates in urine from both gravid and nongravid subjects.

Pharmaceuticals in the environment--a human risk?

Pharmaceuticals in the environment and their potential toxic effects are emerging research areas, which is also reflected in the drug approval regulation. This far, focus has mainly been directed toward potential effects on nature and wildlife. In this paper, human risk as a consequence of exposure via the environment has been addressed and assessed. The synthetic estrogen 17alpha-ethinylestradiol (EE2), the antibiotic phenoxymethylpenicillin (Pen V), and the antineoplastic drug cyclophosphamide (CP) were chosen as modeling substances based on criteria of receptor specificity, elevated risk for human population groups for which the pharmaceuticals are not therapeutically intended, different modes of action, and prescription frequency. Attention has been focused on emissions from the use phase and subsequent diffuse release via the sewer systems. A reasonable worst-case environmental fate and human exposure were estimated using the software EUSES on worst-case emission quantities. The results indicate a negligible human risk connected to the environmental exposure for these substances. Danish conditions have been used as the modeling area, but the results are assumed to be valid for regions with similar drug consumption profiles.

Cytochrome P450 metabolism of estradiol in hamster liver and kidney

Estradiol induces kidney tumors in Syrian hamsters. The elevated conversion of estradiol to 4-hydroxylated metabolites in kidney compared to the predominant 2-hydroxylation in liver and other organs, where tumors are not induced by this treatment, has been proposed to be the basis of estrogen-induced carcinogenesis. In this study, we examined the hepatic and renal enzymes catalyzing the formation of catecholestrogens to understand the differences in estrogen metabolism in these organs. In liver, 2-hydroxylation of estradiol is the major metabolic pathway with 4-hydroxylation a minor by-product and with the formation of both catechols responding coordinately to the same inhibitors. Western blot analysis and inhibition studies suggest that the major form catalyzing hepatic estrogen 2-hydroxylation is a member of the CYP3A family, as previously observed with rat liver microsomes, and that 4-hydroxylation is a by-product of this metabolism. In the kidney, 4-hydroxylation of estradiol appears to be catalyzed by more than one enzyme according to the Eadie-Hofstee analysis. Both 2- and 4-hydroxylation in the kidney are affected differentially by inhibitors and are induced by beta-napthoflavone. Western blots of renal microsomes reveal that CYP1A2 is induced whereas CYP1A1 is detectable in kidney, but not induced by this treatment. Finally, a part of the 2-hydroxylation and a small part of the 4-hydroxylation by kidney microsomes may be catalyzed by a member of the CYP3A family, since these reactions are partially inhibited by CYP3A inhibitors such as progesterone and other progestins, although renal enzyme levels are much lower than those in the liver as revealed by Western blot. Our data suggest that estrogen 2-hydroxylation in the hamster kidney is catalyzed by members of the CYP1A and CYP3A families, which also contribute to 4-hydroxylation. The majority of 4-hydroxyestradiol formation in the hamster kidney may be catalyzed by a form(s) of the newly discovered CYP1B family that has yet to be characterized.

Gas chromatography/mass spectrometry of catechol estrogens

Catecholestrogens (CCEs), namely 2- or 4-hydroxyestradiol and hydroxyestrone, are highly polar, reactive, and extremely labile estrogen metabolites in many experimental conditions. For these reasons, indirect assay methods mainly have been used. Some experimental evidence suggests that CCEs are synthesized and biologically active mostly in target cells. At this level, unfortunately, the indirect assays cannot be used. We present a method of gas chromatographic/mass spectral (GC/MS) analysis for the identification of individual CCEs; the major fragmentation ions of authentic estrogen standards as trimethylsilylether derivatives, and the MS patterns of the major CCEs, namely, 2-hydroxyestradiol and hydroxyestrone, are included. Few examples of CCEs detected in human breast cancer tissues and in breast cyst fluids are reported. Sample extracts were submitted to reversed-phase, high-performance liquid chromatography (RP-HPLC) and were quantified by "on line" electrochemical (EC) detection; thereafter, either crude extracts or single eluted peaks were submitted to GC/MS, by which detection limits of less than 5 pmol were attained. As expected, the molecular ion was the most relevant molecule in all but one case. On the contrary, the other relative intensities of major fragmentation ions M -15, M -30, M -90, and M -15 + (-90) were unevenly distributed, although represented in the majority of cases. In all cases, the GC/MS of peak fractions, purified by RP-HPLC and UV detection, confirmed the results of liquid chromatographic analysis combined with EC detection. In contrast, GC/MS of crude extracts was not equally satisfactory. Comparison of a liquid chromatography system with EC detection and the GC/MS approach revealed some inconsistency in quantitation of individual CCEs.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum concentration and urinary excretion of "classical" estrogens, catecholestrogens and 2-methoxyestrogens in normal human pregnancy

Catecholestrogens, 2-methoxyestrogens and "classical" estrogens (estrone, estradiol, estriol) were measured simultaneously in serum and urine samples of 220 pregnant women from the 8th week of pregnancy until to delivery. From these data we established the central 0.80 centile intervals as time specified reference intervals for each substance analyzed. Serum and urinary estradiol rise steadily during the progress of pregnancy, whereas estrone, catecholestrogens and 2-methoxyestrogens reach a plateau during the last trimester. These observations support the hypothesis, that the amount of the latter compounds may be regulated by separate mechanisms. The values of concentration and excretion of 2- and 4-substituted estrogens varied widely throughout pregnancy. Even very high or very low concentrations of these substances had no recognizable relation to the outcome of pregnancy. This supports the assumption that catecholestrogens and their methylethers are metabolites without any regulatory function in pregnancy.

Identification of oestrogen metabolites in human urine by capillary gas chromatography and mass spectrometry

Oestrogen metabolites from the urine of males and pregnant and non-pregnant females were enriched by a procedure involving column chromatography on adsorber resins, gels and ion exchangers, enzymatic solvolysis and extraction, thereby separating the oestrogens from most of the interfering material. After derivatization of the oestrogens as their trimethylsilyl ethers profiles were measured with a fused silica column and a flame ionization detector by gas chromatography. Using a combination of capillary gas chromatography and mass spectrometry approximately 50 oestrogen metabolites were detected in the human urine of males and females, of which 19 were unknown urine compounds. Not all could be identified definitely owing to the lack of reference material. Mass spectra of trimethylsilylated oestrogens with functional groups at position 11 (11-dehydroestradiol, 11-dehydroestrone and 11 beta-hydroxyestrone) were discussed in their common and discernible fragmentations.

The multicomponent analysis of estrogens in urine by ion exchange chromatography and GC-MS--I. Quantitation of estrogens after initial hydrolysis of conjugates

A method for the multicomponent analysis of estrogens in urine after initial hydrolysis of the conjugates is described. Following protection of the carbonyl functions by ethoximation, estrogen conjugates were extracted on Sep-Pak C18 cartridges and purified on the acetate form of DEAE-Sephadex. The samples were subsequently hydrolysed by Helix pomatia juice and the hydrolysate was purified on the acetate form of QAE-Sephadex. Estrogens with vicinal cis-hydroxyls and diphenolic compounds were fractionated on the borate and bicarbonate form of QAE-Sephadex, respectively. Neutral steroids were removed by the free base form of DEAE-Sephadex after which estrogens were separated into two groups using Lipidex 5000 in a straight phase system. Following trimethylsilyl ether derivatization estrogens were analysed by selected ion monitoring (SIM). The method allows the quantitation of all the important estrogen metabolites including catechol estrogens. It is precise, accurate and sensitive permitting the quantitation of estrogens in urine of males and non-pregnant females.

Profiling steroid hormones and urinary steroids

This paper reviews techniques utilized in the profiling of steroids in body fluids and tissues. Methods for profiling plasma unconjugated steroids and urinary steroid metabolites are focused on. Concentrations or levels of excretion of a variety of steroids have been documented and reviewed. The importance of profiling techniques in the study of normal and pathophysiology of hormonal steroids is discussed.

Steroid metabolism in human teratocarcinoma cell line PA 1

Human ovarian teratocarcinoma cells of line PA 1, (Zeuthen et al., 1979[1]) used as model for early embryonic cells, were analyzed for their in vitro capacity to convert steroids. The cells were incubated for 20 h with radioactive pregnenolone, progesterone, dehydroepiandrosterone, androstenedione, testosterone or estradiol-17 beta, or with non-radioactive progesterone, 6 alpha- or 6 beta-hydroxyprogesterone, 3 beta-hydroxy-5 alpha-pregnan-20-one, dehydroepiandrosterone or estradiol-17 beta. The metabolites were analyzed by thin layer chromatography or studied by gas chromatography-mass spectrometry. The results indicate that PA 1 cells are able to metabolize, although to a restricted amount, a variety of steroids, most markedly progesterone. The metabolites were almost exclusively found in the medium. The main metabolite of progesterone was 3 beta, 6 alpha-dihydroxy-5 alpha-pregnan-20-one. Minor formation of progesterone from pregnenolone could be detected. Human chorionic gonadotropin did not have any effect on pregnenolone metabolism. No formation of estradiol-17 beta or estrone from dehydroepiandrosterone, androstenedione or testosterone could be detected. However, estradiol-17 beta was shown to be converted mainly to estrone. These findings indicate that undifferentiated PA 1 teratocarcinoma cells like certain mouse teratocarcinoma cells, seem not to be steroidogenic but are capable of metabolizing naturally occurring steroid hormones and their precursors.

Separation of oestrogens in biological fluids and synthetic mixtures on Sephadex G-type gels

The separations achieved when mixtures of both free and conjugated oestrogens from a variety of sources are chromatographed on columns of Sephadex gel are reviewed. The molecular identities of oestrogen conjugates which have been separated from human urine by these methods are listed in Table 1. Tables 2 and 3 contain the key experimental details for a total of 26 separations of oestrogen mixtures, abstracted from the total of 20 papers which were published during the period 1961-82. Table 4 details corresponding experimental data for the separation of free oestriol (in human blood) achieved by methods involving a combined Sephadex gel and immunochemical procedure abstracted from a further two papers. A careful analysis of the separation data given in the tables leads to the initial conclusion that the elution profile depends on the expected chromatographic variables for gel filtration chromatography, namely, type of Sephadex gel, length of column, nature and amount of sample applied and the sensitivity of detection methods. However, the separation achieved by the Sephadex columns is also shown to be critically dependent on the column temperature and the pH and chemical composition of the eluent and wash solvents. These latter effects, together with the realization that the molecular weights of the oestrogens being separated are very similar, leads to the conclusion that the separations summarized in Tables 2 and 3 are all being achieved by an absorption process. This being the case, it is suggested that the time-consuming methods of gel filtration chromatography need not be used. Confirmation of this proposal is afforded by a discussion of a recent paper in which the rapid separation of the oestrogens from other components in the biological matrix (urine) was achieved by an adsorption procedure. It is suggested that in the future, separations of oestrogens in biological materials may be most rapidly achieved in combining this type of adsorption procedure with HPLC.

Selective chromatographic fractionation of catechol estrogens on anion exchangers in borate form

The borate form of anion exchangers has been investigated for its utility in the field of estrogen analysis. The borate form of a weak (DEAE-Sephadex A-25) and a strong (QAE-Sephadex A-25) anion exchanger was easily prepared by appropriate washing of the gels, without the need of time consuming immobilization techniques. Estrogens with vicinal cis-hydroxyls were strongly retained in both gels through formation of borate complexes and readily separated from estrogens not possessing such groups. Moreover, borate complex formation with the labile o-dihydroxyphenyl moiety of catechol estrogens fully protected them from decomposition during chromatography. Quantitative recovery of catechol estrogens was thereby obtained without use of antioxidants. The borate form of QAE-Sephadex A-25 was capable, in addition, of separating estrogens not possessing vicinal cis-hydroxyls from the corresponding neutral steroids.