Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An efficient procedure is described for the simultaneous determination of 9 androgen glucuronides including androsterone, etiocholanolone, 11-ketoandrosterone, 11-ketoetiocholanolone, 11beta-hydroxyandrosterone, 11beta-hydroxyetiocholanolone, and dehydroepiandrosterone (DHEA) in 3-glucuronide form and dihydrotestosterone (DHT) and testosterone in 17-glucuronide form from urine specimens. The method involves solid-phase extraction of the urinary steroids using Serdolit PAD-1 resin, with subsequent conversion to methyl ester-trimethylsilyl (Me-TMS) ether derivatives for the direct analysis by gas chromatography-mass spectrometry (GC-MS) using high temperature MXT-1 (Silcosteel-treated stainless steel) capillary column. Upon split injection of Me-TMS steroids at 330 degrees C into the MXT-1 capillary column initially maintained at 300 degrees C then programmed to 322 degrees C at 2 degrees C/min, each androgen glucuronide was well separated in excellent peak shape. The characteristic ions at m/z 217 constituting the base peaks in the electron-impact (20 eV) mass spectra for most steroids permitted their sensitive detection by GC-MS with selected-ion monitoring (SIM), whereas base peak ion at m/z 271 was used for the SIM of dehydroepiandrosterone-3-glucuronide. The detection limits for SIM of most of the steroids were 15 pg except for the 3-glucuronides of 11-ketoandrosterone and 11-ketoetiocholanolone, which could be detected down to 20 pg. The SIM responses were linear with correlation coefficients varying from 0.981 to 0.993 in the concentration range of 20 to 3000 ng/ml for the androgens studied. When applied to urine samples, the present method allowed rapid screening for the 7 androgens in their glucuro-conjugated forms simultaneously with good overall precision and accuracy within the normal concentration ranges of 15.1 to 3124.6 ng/ml.
Steroids 2000 Jan
PMID:Simultaneous determination of urinary androgen glucuronides by high temperature gas chromatography-mass spectrometry with selected ion monitoring. 1062 37

By means of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) urinary steroids obtained from a reference population of 56 subjects were analyzed for their (13)C/(12)C-ratios. The analytes encompassed androsterone (A), etiocholanolone (E), 11beta-hydroxyetiocholanolone (OHE), 11beta-hydroxyandrosterone (OHA), and 5beta-pregnane- 3alpha,20alpha-diol (PD). A and E represent androgen metabolites (AM). PD, OHE, and OHA have sources independent from androgen metabolism. The delta(13)C-values of the latter compounds may be compared to those of AM in order to detect doping with synthetic androgens and thus may serve as endogenous reference compounds (ERC). In order to allow for classification of conspicuous samples, reference ranges and limits were calculated for delta(13)C-values of selected steroids and differences hereof (Delta(13)C-values). When A is compared to ERCs, Delta(13)C-values larger than 3 per thousand are very unlikely. A set of additional parameters was surveyed by a questionnaire. Several factors turned out to exert significant influence on the delta(13)C-values of urinary steroids. These encompass the identity of the steroid itself, sex, oral contraception, travels, and physical activity.
Steroids 2008 Apr
PMID:delta13C-values of endogenous urinary steroids. 1824 1

The question addressed in this study was the nature of the enzyme required to remove the side-chain of 17-hydroxycorticosteroids, leading in the case of cortisol to the excretion of 11beta-hydroxyandrosterone, 11-oxo-androsterone and the corresponding etiocholanolones. We questioned whether it could be CYP17, the 17-hydroxylase/17,20-lyase utilized in androgen synthesis. The conversion of exogenous cortisol to C(19) steroids in patients with complete 17-hydroxylase deficiency (17HD) was studied rationalizing that if CYP17 was involved no C(19) steroids would be formed. The urinary excretion of the four 11-oxy-C(19) steroids as well as many of the major C(21) cortisol metabolites were measured by GC/MS. Our results showed that the conversion of cortisol to C(19) steroids was normal in 17HD indicating that a currently unidentified enzyme must be responsible for this transformation. A secondary goal was to determine to what extent 11-oxy-C(19) steroids were metabolites of cortisol or adrenal synthesized 11beta-hydroxyandrostenedione. Since cortisol-treated 17HD patients cannot produce androstenedione, all C(19) 11-oxy-metabolites excreted must be derived from exogenous cortisol. The extent to which 17HD patients have lower relative excretion of C(19) steroids should reflect the absence of 11beta-hydroxyandrostenedione metabolites. Our results showed almost all of 11-oxo-etiocholanolone and 11beta-hydroxyetiocholanolone were cortisol metabolites, but in contrast the excretion of 11beta-hydroxyandrosterone was less than 10% that of normal individuals, indicating that in excess of 90% must be a metabolite of 11beta-hydroxyandrostenedione.
Steroids 2008 Jul
PMID:17-Hydroxylase/C17,20-lyase (CYP17) is not the enzyme responsible for side-chain cleavage of cortisol and its metabolites. 1835 83

The application of a comprehensive gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS)-based method for stable carbon isotopes of endogenous urinary steroids is presented. The key element in sample preparation is the consecutive cleanup with high-performance liquid chromatography (HPLC) of underivatized and acetylated steroids, which allows the isolation of ten analytes (11beta-hydroxyandrosterone, 5alpha-androst-16-en-3beta-ol, pregnanediol, androsterone, etiocholanolone, testosterone, epitestosterone, 5alpha-androstane-3alpha,17beta-diol, 5beta-androstane-3alpha,17beta-diol and dehydroepiandrosterone) from a single urine specimen. These steroids are of particular importance to doping controls as they enable the sensitive and retrospective detection of steroid abuse by athletes. Depending on the biological background, the determination limit for all steroids ranges from 5 to 10 ng/mL for a 10 mL specimen. The method is validated by means of linear mixing models for each steroid, which covers repeatability and reproducibility. Specificity was further demonstrated by gas chromatography/mass spectrometry (GC/MS) for each analyte, and no influence of the sample preparation or the quantity of analyte on carbon isotope ratios was observed. In order to determine naturally occurring (13)C/(12)C ratios of all implemented steroids, a reference population of n = 61 subjects was measured to enable the calculation of reference limits for all relevant steroidal Delta values.
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PMID:Determination of 13C/12C ratios of endogenous urinary steroids: method validation, reference population and application to doping control purposes. 1853 69