Extractive ethoxycarbonylation in high-temperature gas chromatography–mass spectrometry based analysis of serum estrogens

The evolution of methods for urinary steroid metabolomics in clinical investigations particularly in childhood

The metabolites of cortisol, and the intermediates in the pathways from cholesterol to cortisol and the adrenal sex steroids can be analysed in a single separation of steroids by gas chromatography (GC) coupled to MS to give a urinary steroid profile (USP). Steroids individually and in profile are now commonly measured in plasma by liquid chromatography (LC) coupled with MS/MS. The steroid conjugates in urine can be determined after hydrolysis and derivative formation and for the first time without hydrolysis using GC-MS, GC-MS/MS and liquid chromatography with mass spectrometry (LC-MS/MS). The evolution of the technology, practicalities and clinical applications are examined in this review. The patterns and quantities of steroids changes through childhood. Information can be obtained on production rates, from which children with steroid excess and deficiency states can be recognised when presenting with obesity, adrenarche, adrenal suppression, hypertension, adrenal tumours, intersex condition and early puberty, as examples. Genetic defects in steroid production and action can be detected by abnormalities from the GC-MS of steroids in urine. New mechanisms of steroid synthesis and metabolism have been recognised through steroid profiling. GC with tandem mass spectrometry (GC-MS/MS) has been used for the tentative identification of unknown steroids in urine from newborn infants with congenital adrenal hyperplasia. Suggestions are made as to areas for future research and for future applications of steroid profiling. As routine hospital laboratories become more familiar with the problems of chromatographic and MS analysis they can consider steroid profiling in their test repertoire although with LC-MS/MS of urinary steroids this is unlikely to become a routine test because of the availability, cost and purity of the internal standards and the complexity of data interpretation. Steroid profiling with quantitative analysis by mass spectrometry (MS) after chromatography now provides the most versatile of tests of adrenal function in childhood.

Mass spectrometry-based metabolic signatures of sex steroids in breast cancer

Owing to controversy over the effects of steroids on breast cancer pathophysiology, comprehensive quantification of steroid hormones has been extensively considered in both clinical practice and biomarker discovery studies. In contrast to the traditional immunoaffinity-based assays, which show cross-reactivity and have poor validity at low levels of sex steroids, mass spectrometry is becoming a promising tool for measuring steroid levels in complex biological specimens. The Endocrine Society has announced and continuously updated on technical advances to apply high-quality breakthroughs in the clinical sciences. To avoid incorrect estimation of the steroids of interest, however, further emphasis should be made on the efficient separation by chromatography, such as gas and liquid chromatography, prior to mass spectrometric (MS) detection. Recent advances in MS-based analysis of sex steroids associated with breast cancer enable accurate quantification of circulating as well as localized steroids from frozen tissue slices, allowing these assays to be more powerful in clinical practice.

Improved detectability of sex steroids from frozen sections of breast cancer tissue using GC-triple quadrupole-MS

Sex steroids in clinical endocrinology have been mainly investigated with peripheral blood and urine samples, while there is limited information regarding the local levels within tissues. To improve analytical properties of sex steroids from trace amounts of tissue samples, two-phase extractive ethoxycarbonlyation and subsequent pentafluoropropionyl derivatization coupled to gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed. The optimized analytical conditions led to excellent chromatographic separation of 15 estrogens, 6 androgens, and 2 progestins. The quantitative results were calculated based on in-house control samples as the steroid-free tissues, and the precision and accuracy were 4.2%-26.8% and 90.8%-116.4%, respectively. The on-column limit of quantification was from 180 fg to 0.5 pg for androgens and estrogens, and 1.25 pg for progestins, which were found to be linear (r²> 0.990). The validated method was then applied to quantify 7 sex steroids from three 100-μm-thick frozen breast tissue slices from postmenopausal patients with breast cancer. This is the first report on the improved GC-MS/MS method for the detection of androgens and pregnenolone from breast cancer tissues, and it can be a useful technique to measure the local levels of sex steroids, thus, enhancing our understanding of the pathophysiological significances of steroidogenesis.

Metabolic profiling of cholesterol and sex steroid hormones to monitor urological diseases

Cholesterol and sex steroid hormones including androgens and estrogens play a critical role in the development and progression of urological diseases such as prostate cancer. This disease remains the most commonly diagnosed malignant tumor in men and is the leading cause of death from different cancers. Attempts to understand the role of cholesterol and steroid metabolism in urological diseases have been ongoing for many years, but despite this, our mechanistic and translational understanding remains elusive. In order to further evaluate the problem, we have taken an interest in metabolomics; a discipline dedicated to the systematic study of biologically active metabolites in cells, tissues, hair and biofluids. Recently, we provided evidence that a quantitative measurement of cholesterol and sex steroid metabolites can be successfully achieved using hair of human and mouse models. The overall goal of this short review article is to introduce current metabolomic technologies for the quantitative biomarker assay development and also to provide new insight into understanding the underlying mechanisms that trigger the pathological condition. Furthermore, this review will place a particular emphasis on how to prepare biospecimens (e.g., hair fiber), quantify molecular profiles and assess their clinical significance in various urological diseases.