Determination Of Plasma Corticosteroids Research Articles

Determination of corticosteroids in plasma by high-performance liquid chromatography after pre-column derivatization with 2-(4-carboxyphenyl)-5,6-dimethylbenzimidazole.

2-(4-Carboxyphenyl)-5,6-dimethylbenzimidazole (CDB) was used as a pre-column derivatization reagent for corticosteroids analysed by high-performance liquid chromatography with fluorimetric detection. Eight corticosteroids were derivatized with CDB to their esters in acetonitrile containing 4-piperidinopyridine and 1-isopropyl-3-(3-dimethylaminopropryl)carbodiimide perchlorate. The resulting CDB esters were extracted with a Sep-Pak C18 cartridge and the esters were separated on a reversed-phase column (Zorbax ODS) with water-methanol (25:75, v/v) containing 5 mmol/l tetramethylammonium hydrogensulphate as the mobile phase. The limits of detection for steroids were 0.06-0.3 pg per 100 microliters of plasma (signal-to-noise = 3). The within-day relative standard deviations (n = 6) were 7.8-11.1%, and day-to-day relative standard deviations (n = 6) were 7.0-10.4%.

Spironolactone and plasma cortisol

Spironolactone has been shown to interfere with the determination of corticosteroids in plasma and urine. In the present study the fluorimetric method of Mattingly was used to determine how rapidly the spurious elevation of plasma cortisol develops after spironolactone administration and to define the rate of disappearance of the artifact from plasma. In normal subjects plasma cortisol levels increased by more than 100% 60 minutes after a single 50 mg oral dose of spironolactone. The maximal concentration of plasma cortisol was observed at 2 hours and the level slowly declined thereafter, reaching pretreatment values 72 hours after administration of the drug.

Determination of plasma corticosteroids and urinary cortisol by a competitive protein-binding method using dextran-coated charcoal

Corticosteroid-binding globulin and dextran-coated charcoal have been used to measure the corticosteroids in plasma and the free cortisol in urine. 0.5 ml of plasma or 1.0 ml of urine was extracted with methylene chloride and the extract washed with sodium hydroxide and water. The extract was dried, dissolved in a standard plasma pool containing [1,2- 3H]11-deoxycortisol. Dextran-coated charcoal was employed to separate protein-bound and unbound corticosteroid. The method has a high degree of precision and accuracy. The specificity was good in plasma; in urine the values of CBG-charcoal method were higher than the values found by a competitive binding method after purification of extracts with paper chromatography.

Interference of Heparin Containing Benzyl Alcohol in the Fluorometric Determination of Plasma Corticosteroids

Journal Article Interference of Heparin Containing Benzyl Alcohol in the Fluorometric Determination of Plasma Corticosteroids Get access The Journal of Clinical Endocrinology & Metabolism, Volume 27, Issue 9, 1 September 1967, Pages 1350–1352, https://doi.org/10.1210/jcem-27-9-1350 Published: 01 September 1967

The diagnosis and differential diagnosis of Cushing's syndrome by means of an abbreviated dexamethasone test in the determination of corticosteroids in plasma

Der Dexamethason-Test nachLiddle (1960) hat die klinischen Untersuchungsmoglichkeiten bei der Diagnose und Differentialdiagnose des Cushing-Syndroms wesentlich bereichert. Nachteilig ist neben der Dauer des Testes vor allem die Notwendigkeit, den Harn uber mehrere Tage gewissenhaft zu sammeln. Bestimmungen des Corticosteroidspiegels im Plasma haben diesen Nachteil nicht. Daruber hinaus ergeben sich durch die Einfachheit, Schnelligkeit und Billigkeit neuerer Methoden (fluorometrische Bestimmung der 11-OHCS im Plasma) zusatzliche Vorteile. Die vorgelegten Befunde uber einen standardisierten „Kurz“-Dexamethason-Test unter Bestimmung der Corticosteroide im Plasma ergaben eine absolute Zuverlassigkeit des Testes bei der differentialdiagnostischen Abgrenzung des Cushing-Syndroms von der einfachen Adipositas sowie von Pseudoformen des Cushing-Syndroms mit einem oder mehreren klinischen Zeichen des Hypercorticismus. Bei 61 Nebennierengesunden einschlieslich der Adiposen und der Pseudo-Cushing-Patienten wurde nach 3 mg Dexamethason, zwischen 17 und 8 Uhr oral gegeben, um 9 Uhr des folgenden Tages eine 11-OHCS-Konzentration von 3,2±1,1 µg/100 ml Plasma gemessen, wahrend bei 12 Patienten mit Cushing-Syndrom ein Mittelwert von 17,2±9,1 µg/100 ml ermittelt wurde. Eine Uberlappung der beiden Kollektive fand sich nicht, im Gegensatz zu den Werten unter Basalbedingungen. Unter Fortfuhrung des Dexamethason-Testes mit einer Dosierung von 8 mg/24 Std reagierten nur 3 von 7 Cushing-Kranken mit einem weiteren deutlichen Abfall des Corticosteroidspiegels. Diese 3 Patienten boten im Gegensatz zu den 4 anderen ein klinisch relativ leichtes Krankheitsbild. Die mogliche Ursache dieses unterschiedlichen Verhaltens wahrend des 8 mg-Dexamethason-Testes wird diskutiert.

FLUORIMETRIC DETERMINATION OF ADRENAL CORTICOSTEROIDS: OBSERVATIONS ON INTERFERING FLUOROGENS IN HUMAN PLASMA.

SUMMARY Simple fluorimetric methods for the determination of corticosteroids are not sufficiently specific to allow the accurate estimation of low concentrations in plasma. It has been noted previously and is confirmed here, that the measured fluorescence is not proportional to the volume of plasma used, but includes a component which is relatively independent of the plasma volume extracted. This gives rise to a positive intercept on the fluorescence axis when fluorescence intensity is plotted against volume. The suggestion that the determination of plasma corticosteroids can be made specific by subtracting the value of this intercept from the measured fluorescence intensity of the plasma sample has been examined. In the light of experimental data and certain theoretical considerations presented here, this suggestion is rejected. It is concluded that the inaccuracy due to interfering fluorogens can be reduced by taking fluorimeter readings within 5 min. of extraction into the fluorescence reagent, but that even then specificity is not complete.

COMPARISON OF THREE TECHNIQUES FOR THE FLUORIMETRIC DETERMINATION OF PLASMA CORTICOSTEROIDS.

SUMMARY The previously reported method (De Moor, Steeno, Raskin, Hendrikx & De Tremerie, 1959) for the fluorimetric determination of plasma corticosteroids (cortisol plus corticosterone) has been further simplified and compared with two more elaborate methods intended to determine cortisol more specifically (Van der Vies, 1961; Braunsberg & James, 1962). For normal subjects there is a good relation between results obtained by the simplest method and those obtained by the two others. On the other hand, the latter two techniques give less specific fluorescence and higher reagent blanks. The background fluorescence of the simplified assay has been further studied and was found to lie between 1 and 1·5 μg./100 ml.

Laboratory studies after intrathecal corticosteroids: determination of corticosteroids in plasma and cerebrospinal fluid.

Introduction Methylprednisolone acetate * has been administered intrathecally in more than 1,000 patients for the treatment of neurologic disorders 1-3 during the last three years. The treatment has proved safe, and the results are encouraging. It has become a standard method of treatment for arachnoiditis resulting from trauma, Pantopaque, or laminectomy. With this new method of administration we thought it expedient to ascertain: first, how long methylprednisolone acetate remains in the cerebrospinal fluid after intrathecal administration; secondly, whether methylprednisolone acetate injected at the lumbar level is dispersed evenly throughout the subarachnoid space, or remains in a higher concentration at the site of injection, by analyzing fluids obtained simultaneously at lumbar and cisternal punctures; thirdly, the duration of action of the steroid as judged by the effect on endogenous secretion of corticosteroids; fourthly, the effect on spinal fluid pressure, protein and cell content of various amounts of methylprednisolone acetate. Methods, Procedures, and

One‐hour Subcutaneous AGTH Test with Determination of Plasma Corticosteroids

One‐hour Subcutaneous AGTH Test with Determination of Plasma Corticosteroids