Simultaneous pharmacokinetic and pharmacodynamic analysis of 5α-reductase inhibitors and androgens by liquid chromatography tandem mass spectrometry

Upreti, Rita; Naredo, Gregorio; Faqehi, Abdullah M.M.; Hughes, Katherine; Stewart, Lawrence H.; Walker, Brian R.; Homer, Natalie; Andrew, Ruth

doi:10.1016/j.talanta.2014.07.087

Cited by 18 publications

(13 citation statements)

References 42 publications

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“…These cartridges showed excellent retention of analytes, and generated a clean extract with reproducible high recovery. Initial development using Oasis® HLB [8] , [22] , [23] , [24] showed excellent recoveries from water (mean±RSD; E1 99±4%, E2 97±2%, 13 C 2 E1 98±10% and 13 C 2 E2 96±5%), but significant ion suppression was identified in the plasma extracts ( 13 C 2 E1 35%, 13 C 2 E2 32% versus unextracted standards). Previous problems with ion suppression of derivatized estrogens by phospholipids have been reported [21] and were overcome with online ion-exchange chromatography.…”

Section: Resultsmentioning

confidence: 99%

“…For method application, serum was collected from 27 pre-menopausal women undergoing investigations for menstrual disorders (24–52 years old); these patient samples were anonymised prior to analysis and ethical approval was thus not required for this method development study. Further plasma samples were obtained from subjects participating in experimental medicine studies for which local ethical approval had been obtained; 20 post-menopausal women (58–60 years old) and 48 men (21–85 years old) men [22] .…”

Section: Methodsmentioning

confidence: 99%

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Derivatization of estrogens enhances specificity and sensitivity of analysis of human plasma and serum by liquid chromatography tandem mass spectrometry

Faqehi

Cobice

Naredo

et al. 2016

Talanta

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Estrogens circulate at concentrations less than 20 pg/mL in men and postmenopausal women, presenting analytical challenges. Quantitation by immunoassay is unreliable at these low concentrations. Liquid chromatography tandem mass spectrometry (LC–MS/MS) offers greater specificity and sometimes greater sensitivity, but ionization of estrogens is inefficient. Introduction of charged moieties may enhance ionization, but many such derivatives of estrogens generate non-specific product ions originating from the “reagent” group. Therefore an approach generating derivatives with product ions specific to individual estrogens was sought.Estrogens were extracted from human plasma and serum using solid phase extraction and derivatized using 2-fluoro-1-methylpyridinium-p-toluenesulfonate (FMP-TS). Electrospray in positive mode with multiple reaction monitoring using a QTrap 5500 mass spectrometer was used to quantify “FMP” derivatives of estrogens, following LC separation.Transitions for the FMP derivatives of estrone (E1) and estradiol (E2) were compound specific (m/z 362→238 and m/z 364→128, respectively). The limits of detection and quantitation were 0.2 pg on-column and the method was linear from 1–400 pg/sample. Measures of intra- and inter-assay variability, precision and accuracy were acceptable (<20%). The derivatives were stable over 24 h at 10 °C (7–9% degradation). Using this approach, E1 and E2, respectively were detected in human plasma and serum: pre-menopausal female serum (0.5 mL) 135–473, 193–722 pmol/L; male plasma (1 mL) 25–111, 60–180 pmol/L and post-menopausal female plasma (2 mL), 22–78, 29–50 pmol/L.Thus FMP derivatization, in conjunction with LC–MS/MS, is suitable for quantitative analysis of estrogens in low abundance in plasma and serum, offering advantages in specificity over immunoassay and existing MS techniques.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Derivatization of estrogens enhances specificity and sensitivity of analysis of human plasma and serum by liquid chromatography tandem mass spectrometry

Faqehi

Cobice

Naredo

et al. 2016

Talanta

Self Cite

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“…Plasma T and androstenedione were quantified by liquid chromatography and tandem mass spectrometry (LC-MS/MS) ( 17 ), adapted for smaller volume of plasma (30 μL), and using Oasis HLB 10 mg cartridges (Waters). Estradiol and estrone were quantified by LC-MS/MS ( 18 ).…”

Section: Methodsmentioning

confidence: 99%

Aromatase Inhibition Reduces Insulin Sensitivity in Healthy Men

Gibb

Homer

Faqehi

et al. 2016

The Journal of Clinical Endocrinology & Metabolism

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Context:Deficiency of aromatase, the enzyme that catalyzes the conversion of androgens to estrogens, is associated with insulin resistance in humans and mice.Objective:We hypothesized that pharmacological aromatase inhibition results in peripheral insulin resistance in humans.Design:This was a double-blind, randomized, controlled, crossover study.Setting:The study was conducted at a clinical research facility.Participants:Seventeen healthy male volunteers (18–50 y) participated in the study.Intervention:The intervention included oral anastrozole (1 mg daily) and placebo, each for 6 weeks with a 2-week washout period.Main Outcome Measure:Glucose disposal and rates of lipolysis were measured during a stepwise hyperinsulinemic euglycemic clamp. Data are mean (SEM).Results:Anastrozole therapy resulted in significant estradiol suppression (59.9 ± 3.6 vs 102.0 ± 5.7 pmol/L, P = < .001) and a more modest elevation of total T (25.8 ± 1.2 vs 21.4 ± 0.7 nmol/L, P = .003). Glucose infusion rate, during the low-dose insulin infusion, was lower after anastrozole administration (12.16 ± 1.33 vs 14.15 ± 1.55 μmol/kg·min, P = .024). No differences in hepatic glucose production or rate of lipolysis were observed.Conclusion:Aromatase inhibition reduces insulin sensitivity, with respect to peripheral glucose disposal, in healthy men. Local generation and action of estradiol, at the level of skeletal muscle, is likely to be an important determinant of insulin sensitivity.

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“…Plasma androgens (testosterone and androstenedione) were analyzed by adapting a previously described method ( 17 ). Briefly, steroids were extracted from plasma (500 μL) by solid-phase extraction on an HLB Oasis (60-mg, 3-cc columns; Waters UK, Elstree, UK) with 10 ng 13 C 3 -testosterone and 13 C 3 -androstenedione (Sigma Aldrich, Dorset, UK) as internal standards.…”

Section: Methodsmentioning

confidence: 99%

Dysregulation of Cortisol Metabolism in Equine Pituitary Pars Intermedia Dysfunction

et al. 2018

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Equine Cushing disease [pituitary pars intermedia dysfunction (PPID)] is a common condition of older horses, but its pathophysiology is complex and poorly understood. In contrast to pituitary-dependent hyperadrenocorticism in other species, PPID is characterized by elevated plasma ACTH but not elevated plasma cortisol. In this study, we address this paradox and the hypothesis that PPID is a syndrome of ACTH excess in which there is dysregulation of peripheral glucocorticoid metabolism and binding. In 14 horses with PPID compared with 15 healthy controls, we show that in plasma, cortisol levels and cortisol binding to corticosteroid binding globulin were not different; in urine, glucocorticoid and androgen metabolites were increased up to fourfold; in liver, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) expression was reduced; in perirenal adipose tissue, 11β-HSD1 and carbonyl reductase 1 expression was increased; and tissue cortisol levels were not measurably different. The combination of normal plasma cortisol with markedly enhanced urinary cortisol metabolite excretion and dysregulated tissue-specific steroid-metabolizing enzymes suggests that cortisol clearance is increased in horses with PPID. We infer that the ACTH excess may be compensatory and pituitary pathology and autonomous secretion may be a secondary rather than primary pathology. It is possible that successful therapy in PPID may be targeted either at lowering ACTH or, paradoxically, at reducing cortisol clearance.

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Simultaneous pharmacokinetic and pharmacodynamic analysis of 5α-reductase inhibitors and androgens by liquid chromatography tandem mass spectrometry

Cited by 18 publications

References 42 publications

Derivatization of estrogens enhances specificity and sensitivity of analysis of human plasma and serum by liquid chromatography tandem mass spectrometry

Derivatization of estrogens enhances specificity and sensitivity of analysis of human plasma and serum by liquid chromatography tandem mass spectrometry

Aromatase Inhibition Reduces Insulin Sensitivity in Healthy Men

Dysregulation of Cortisol Metabolism in Equine Pituitary Pars Intermedia Dysfunction

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