Analysis of corticosteroids in equine urine by liquid chromatography–mass spectrometry

Tang, Ping; Law, Wing-Ki; Wan, Terence S.M.

doi:10.1016/s0378-4347(00)00613-7

Cited by 61 publications

(41 citation statements)

References 19 publications

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“…Liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry are specific and offer simpler approaches to sample preparation without sample derivatization steps. Recently, several LC-MS-based methods that use different ion sources were reported for the determination of the following steroid hormones: testosterone [37][38][39], cortisol [40][41][42][43][44], 11-deoxycortisol [45], androstenedione [38,39], DHEA [46], DHEA-S [38,46], progesterone [47], 17-hydroxyprogesterone [48], estriol [49], and estradiol [38,49].…”

Section: Methods Of Measurementmentioning

confidence: 99%

Steroid hormones: relevance and measurement in the clinical laboratory

Holst

Soldin

Guo

et al. 2004

Clinics in Laboratory Medicine

133

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The steroid hormones are synthesized in the adrenal cortex, the gonads, and the placenta; are all derived from cholesterol and many are of clinical importance. Steroid hormones are synthesized in the mitochondria and smooth endoplasmic reticulum. Because they are lipophilic, they cannot be stored in vesicles from which they would diffuse easily and are therefore synthesized when needed as precursors. Upon stimulation of the parent cell, steroid hormone precursors are converted to active hormones and diffuse out of the parent cell by simple diffusion as their intracellular concentration rises.Because all steroid hormones are derived from cholesterol, they are not soluble in plasma and other body fluids. As a result, steroids are bound to transport proteins that increase their half-life and insure ubiquitous distribution. The protein-bound steroids are in equilibrium with a small fraction of free steroids, which are 'active.' Steroids can act quickly, by binding to cell surface receptors, or slowly, by binding to cytoplasmic or nucleic receptors and ultimately activate gene transcription.The adrenal glands are composed of the adrenal medulla and the adrenal cortex. The adrenal cortex is divided into three major anatomic zones: the zona glomerulosa, which produces aldosterone; and the zonae fasciculata and reticularis, which together produce cortisol and adrenal androgens. The medulla synthesizes catecholamines. More than 30 steroids are produced in the adrenal cortex; they can be divided into three functional categories: mineralocorticoids, glucocorticoids, and androgens.The steroids that are made almost exclusively in the adrenal glands are cortisol, 11-deoxycortisol, aldosterone, corticosterone, and 11-deoxycorti-costerone. Most other steroid hormones, including the estrogens, are made by the adrenal glands and the gonads [ MineralocorticoidsThe mineralocorticoids are formed in the zona glomerulosa. The main function of the mineralocorticoids is to promote tubular reabsorption of sodium and secretion of potassium and hydrogen ions at the collecting tubule, distal tubule, and collecting ducts [2]. When sodium is reabsorbed, water is absorbed simultaneously. The absorption of sodium and water increases fluid volume and arterial pressure.Aldosterone is the most potent mineralocorticoid and accounts for about 90% of the total mineralocorticoid activity. Mineralocorticoid potency in descending order is: aldosterone, 11-deoxycorticosterone, 18-oxocortisol, corticosterone, and cortisol [1]. Although cortisol has mainly glucocorticoid activity, it also has some mineralocorticoid activity. Cortisol has 1/400 of the potency of aldosterone, but its concentration is about 80 times greater than that of aldosterone [4]. The adrenal production of cortisol is approximately 25 mg/day and that of aldosterone is 100μg/day. Corticosterone has mainly glucocorticoid activity and some mineralocorticoid activity.Aldosterone secretion is regulated primarily by the renin-angiotensin system; it also is stimulated by increased serum potas...

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Section: Methods Of Measurementmentioning

confidence: 99%

Steroid hormones: relevance and measurement in the clinical laboratory

Holst

Soldin

Guo

et al. 2004

Clinics in Laboratory Medicine

133

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“…18 -20 LC/MS has been used for the quantification of hydrocortisone in equine urine, either by using a tandem solid-phase extraction (SPE) method 10 or with liquid-liquid extraction. 11,12 An approach to sample preparation for urine analysis with LC/MS is to exclude the preparation step altogether or 'dilute and shoot'. This approach is possible when sample levels of targeted analytes are relatively high and the matrix components do not co-elute or otherwise interfere with the ionization of the analytes.…”

Section: Hydrocortisonementioning

confidence: 99%

Direct injection LC/ESI‐MS horse urine analysis for the quantification and identification of threshold substances for doping control. I. Determination of hydrocortisone

et al. 2008

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Two simple and rapid LC/MS methods with direct injection analysis were developed and validated for the quantification and identification of hydrocortisone in equine urine using the same sample preparation but different mass spectrometric systems: ion trap mass spectrometry (IT-MS) and time-of-flight mass spectrometry (TOF-MS). The main advantage of the proposed methodology is the minimal sample preparation procedure, as particle-free diluted urine samples were directly injected into both LC/MS systems. Desonide was used as internal standard (IS). The linear range was 0.25-2.5 microg ml(-1) for both methods. Matrix effects were evaluated by preparing and analyzing calibration curves in water solutions and different horse urine samples. A great variation of the signal both for hydrocortisone and the internal standard was observed in different matrices. To overcome matrix effects, the unavailability of blank matrix and the excessive cost of the isotopically labeled internal standard, standard additions calibration method was applied. This work is an exploration of the performance of the standard additions approach in a method where neither nonisotopic internal standards nor extensive sample preparation is utilized and no blank matrix is available. The relative standard deviations of intra and interday analysis of hydrocortisone in horse urine were lower than 10.2 and 5.4%, respectively, for the LC/IT-MS method and lower than 8.4 and 4.4%, respectively, for the LC/TOF-MS method. Accuracy (bias percentage) was less than 9.7% for both methods.

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“…However, separation of betamethasone and dexamethasone has been performed by using a suitable gradient and efficient RPs [9,10]. A silica column with derivatization [11] and octadecylsilane stationary phase with water/THF as eluent [12] also allows a good separation using isocratic mode.…”

Section: Introductionmentioning

confidence: 99%

Effect of organic modifier and temperature on the resolution of betamethasone and dexamethasone using a porous graphitic carbon column: Application to their identification and confirmation in human urine by LC‐ESI‐MS/MS

Oueslati

Hamida

Toumi

et al. 2007

J of Separation Science

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The effects of temperature, organic modifier and the type of acid on the retention factor, the resolution and peak shape of betamethasone and dexamethasone are described. The study is performed using narrow bore porous graphitic carbon (PGC) columns online with diode-array detector (DAD) and ESI MS/MS. The results show that temperature affects the retention behaviour of the two compounds and ACN yields the best separation while no effect is obtained by changing the type of organic acid. The developed method is applied for the confirmation of dexamethasone and betamethasone in human urine.

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Analysis of corticosteroids in equine urine by liquid chromatography–mass spectrometry

Cited by 61 publications

References 19 publications

Steroid hormones: relevance and measurement in the clinical laboratory

Steroid hormones: relevance and measurement in the clinical laboratory

Direct injection LC/ESI‐MS horse urine analysis for the quantification and identification of threshold substances for doping control. I. Determination of hydrocortisone

Effect of organic modifier and temperature on the resolution of betamethasone and dexamethasone using a porous graphitic carbon column: Application to their identification and confirmation in human urine by LC‐ESI‐MS/MS

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