A quantitative analysis of total and free 11-oxygenated androgens and its application to human serum and plasma specimens using liquid-chromatography tandem mass spectrometry.

Bioactive 11-oxygenated C adrenal-derived steroids (11-oxy C) are potentially relevant in diverse endocrine and metabolic contexts. We report the development and validation of a liquid chromatography electrospray ionization tandem mass spectrometric method (LC-ESI-MS/MS) for the simultaneous quantification of seven 11-oxy C using 200 µL of plasma or serum. Sample preparation involved chemical derivatization using hydroxylamine after liquid-liquid extraction to improve specificity and sensitivity. The method allowed the quantitation of total 11-oxy C (free + sulfate and glucuronide conjugates) following enzymatic hydrolysis. This included the abundant precursor 11-hydroxyandrostenedione (11OHA4) and the most potent androgenic derivatives 11-keto-testosterone (11KT) and 11-keto-dihydrotestosterone (11KDHT), their abundant metabolites 11-hydroxyandrosterone (11OHAST) and 11-keto-androsterone (11KAST) potentially feeding back into the pool of potent androgens, in addition to 11-keto-androstenedione (11KA4) and 11-hydroxytestosterone (11OHT). Stable isotopes were used as internal standards, and calibrators and quality controls were prepared in the same matrix as the study samples. Performance was validated against the Food and Drug Administration Criteria. The method was sensitive with lower limit of quantification (LLOQ) values of 10 and 20 pg/mL for free and total 11-oxy C, respectively. The applicability was demonstrated in men and women adult donors that showed sex-differences. All steroids were quantified well above LLOQ, except 11KDHT that remained undetectable suggesting interfering endogenous molecules present in non-derivatized samples in which a peak was observed. By providing accurate and reliable quantitative data, this method will permit to evaluate how profiling of 11-oxy C will be most informative as diagnostic, prognostic and/or theranostic tools.