Separation of urinary oestrogen sulphates from oestrogen glucosiduronates on diethylaminoethyl-Sephadex columns

Chromatography as a reference technique for the determination of clinically important steroids

Chromatographic methods (paper chromatography, thin layer chromatography, high performance liquid chromatography, gas chromatography and gas chromatography-mass spectrometry) for the determination of clinically important steroids in biological specimens are reviewed. The emphasis is on the use of gas chromatography, gas chromatography-mass spectrometry and high performance liquid chromatography as reference rather than routine techniques. Chromatographic methods are compared with colorimetric, fluorimetric and radioimmunoassay procedures in terms of simplicity of operation, cost and ability to analyse large numbers of specimens. The importance of correct specimen collection and storage are discussed. Sample preparation techniques for the various analytical methods are described. These include extraction of free and conjugated steroids from serum, plasma, urine and saliva by solvent partition, with polymer-based resins such as Amberlite XAD-2, DEAE-Sephadex and Sephadex resins bonded with various other function groups and, more recently, with chemically bonded reversed-phase silicas.

The multicomponent analysis of estrogens in urine by ion exchange chromatography and GC-MS--II. Fractionation and quantitation of the main groups of estrogen conjugates

A method for the metabolic profiling of estrogen conjugates in urine is described. It mainly involves protection of carbonyl functions by ethoximation, solid extraction on Sep-Pak C18 cartridges, a number of ion exchange chromatographic steps and quantitation by capillary GC or GC-MS. The acetate form of DEAE-Sephadex is used to initially separate estrogen conjugates into four groups; unconjugated, monoglucuronides, monosulfates and double conjugates. Monoglucuronides are further subfractionated to A- and D-ring glucuronides by carbodiimide methylation of the carboxylic functions and chromatography on the free base form of DEAE-Sephadex. Double conjugates are subfractionated to disulfates and sulfoglucuronides by solvolysis and chromatography on the acetate form of DEAE-Sephadex. After the appropriate enzymatic hydrolysis or solvolysis procedures the liberated free estrogens are purified and fractionated by a series of anion exchange chromatographic steps. Finally, following trimethylsilyl ether derivatization estrogens are analysed by capillary GC or GC-MS. The method permits the quantitation of the main conjugates of all the important estrogen metabolites including catechol estrogens. The method is precise, the sensitivity depending on the quantitation mode employed GC or SIM GC-MS. The method was applied to seven late pregnancy urines the values of which are presented.

Testosterone metabolites in dog bile

Testosterone-1,2-3H was injected intravenously into a male dog with a bile fistula and bile and urine collected. The radioactivity was excreted preponderantly in bile (52% of the injected dose) in 6 hours; only 12% appeared in the urine. Methods to study the biliary metabolites of testosterone in this and other animals were developed. Satisfactory conjugate patterns were obtained by fractionation on DEAE-Sephadex A-25 columns using two different elution systems. In addition to an unchanged fraction, six different monoglucuronide fractions were separated. No other conjugates were isolated. Lipidex 5000 column chromatography, TLC and paper chromatography were used for the isolation and purification of aglycone metabolites, which were further identified by co-crystallization methods. The biliary metabolites of testosterone were epiandrosterone (3beta-hydroxy-5alpha-androstan-17-one), etiocholanlone (3alpha-hydroxy-5beta-androstan-17-one), 5alpha-androstan-3beta, 17beta-diol, 5beta-androstan-3alpha, 17beta-diol and 5beta-androstan-3beta,17beta-diol.

Aflatoxin P-1: a new aflatoxin metabolite in monkeys

A new phenolic derivative of aflatoxin B(1), appearing mainly in conjugated form, was identified as the principal urinary metabolite of aflatoxin B(1) in rhesus monkeys. Its identification in human urine might facilitate estimation of aflatoxin exposure in human populations.