Analysis of natural corticosteroids in adrenal extracts and in biological fluids by high-performance liquid chromatography

Corticosteroid biosynthesis in the interrenal cells of the teleost fish, Oreochromis mossambicus

Applying high-performance liquid chromatography and thin-layer chromatography to separate corticosteroids, we studied the biosynthesis of steroids by the interrenal cells of the head kidneys (the adrenocortical homolog) of Oreochromis mossambicus. Intact head kidneys converted exogenous 17 alpha-hydroxyprogesterone into mainly cortisol, but 11-deoxycortisol, cortisone, and androstenedione were also recovered from the medium. Incubation of intact tissue with pregnenolone in addition resulted in the formation of large amounts of an unidentified product, which was absent in incubations of tissue homogenates with pregnenolone.

High-performance liquid chromatography of steroid hormones

Although a considerable amount of work has been carried out in the last ten years in developing methods for the separation of steroids by HPLC, it is still not widespread for the reasons discussed above. There is however no doubt that further developments in HPLC technology, in increasing sensitivity and/or specificity of detection systems, perhaps with microbore columns, may lead to an increase in the use of this powerful analytical procedure as an additional separation method to improve specificity of assay. Solution of the problem of simple interfacing of HPLC systems with mass spectrometers (discussed in another chapter by Games) should further increase the application of HPLC. HPLC is of particular value in providing a means of separating unstable compounds prior to assay by relatively nonspecific quantitation methods. Most steroids do not fall into this category, but the steroid vitamin D and its metabolites do and HPLC has proved in this area to be invaluable (see chapter by Jones & DeLuca). There are a multiplicity of different HPLC systems for the separation of steroids, varying in column type (and manufacturer), solvent composition and method of elution, temperature of elution, etc., and only a few attempts have been made to rationalise these data. It would therefore seem that a fruitful area of future study would be the investigation of computerised systems for the selection and optimisation of HPLC systems for particular steroid separations.

HPLC isolation and GC-MS characterization of a compound strongly cross reacting with tetrahydroaldosterone antiserum

Urines from patients with hypertension and elevated aldosterone levels, i.e. primary aldosteronism due to adrenal adenoma or hyperplasia or carcinoma were extracted, paper chromatographed and thereafter chromatographed repeatedly with normal phase and repeatedly with reversed phase HPLC systems in an attempt to find new metabolites of aldosterone. Specific 3 alpha-hydroxy-5 beta-tetrahydroaldosterone antiserum was used in a radioimmunoassay system to detect possible aldosterone metabolites in the HPLC fractions after each isolation step. The immunoactive HPLC fractions were derivatized and analysed by GC-MS. A relatively nonpolar compound, 11 beta:18(S),18:20 alpha-diepoxy-5 beta-pregnan-3 alpha-ol, was isolated and identified in this manner. This material was originally described by Kelly et al., in 1962 after loading human subjects with huge amounts (25-160 mg) of exogenous aldosterone. This material has not yet been described from endogenously produced aldosterone. Very small amounts, if any, were similarly isolated from the urine of a control subject. Therefore, this compound could prove to be a new marker for hypertension due to hyper-production of aldosterone.

Separation of the major adrenal steroids by reversed-phase high-performance liquid chromatography

The major adrenal steroids were separated by multistep gradient elution with a reversed-phase high-performance liquid chromatography system, employing water and 1-propanol as solvents. With this solvent system, a wide range of 21 5-ene-3 beta-ol and 4-ene-3-one steroids can be resolved in a single chromatogram, which was not possible with previously published gradient solvent systems. In particular, intermediate steroids of the biosynthetic pathway, 17 alpha-hydroxyprogesterone, 17 alpha-hydroxypregnenolone, and dehydroepiandrosterone, were separated with baseline or sufficient resolution to allow accurate quantitation. Using the 1-propanol-water gradient, the separations of 5-ene and 4-ene steroids were compared on different octadecylsilyl packings. Optimum resolution was obtained with a fully covered, spherical particle. The 1-propanol-water gradient was compared to a previously published methanol-water gradient in the analysis of steroidogenesis by adrenocortical cell cultures. HPLC analysis of the steroid production was quantitatively the same with both gradient solvent systems. However, qualitatively, the methanol-water gradient system did not resolve the above-mentioned intermediate steroids.

Determination of 17-hydroxycorticosteroids in urine by fluorescence high-performance liquid chromatography using Dns-hydrazine as a pre-column labeling reagent

A method is described for the determination of urinary 17-hydroxycorticosteroids using fluorescence high-performance liquid chromatography. After enzymatic hydrolysis, 17-hydroxycorticosteroids were extracted using an Extrelut column and then labeled with Dns-hydrazine in hydrochloric acid-ethanol solution. The labeled steroids were chromatographed on a microparticulate silica gel column, the mobile phase was dichloromethane-ethanol-water (900:60:40). The eluate was monitored on a fluorophotometer at 365 nm (excitation) and 505 nm (emission). Linearity of the fluorescence intensities (peak heights) of various 17-hydroxycorticosteroids were obtained between 60 pg and 20 ng. The assay was sensitive, precise and accurate. Comparison with the results obtained by radioimmunoassay gave correlation coefficients of 0.932 for tetrahydrocortisol and 0.930 for tetrahydrocortisone. The proposed method is clinically useful for the routine analysis of urinary 17-hydroxycorticosteroids.

Separation of some natural and synthetic corticosteroids in biological fluids and tissues by high-performance liquid chromatography

A high-performance liquid chromatography (HPLC) technique was developed for the determination of radiolabeled triamcinolone acetonide (TAC), cortisol and their metabolites in rhesus monkey plasma, urine and tissue samples. After protein precipitation, the parent compounds and metabolites were simultaneously resolved using a single-column reversed-phase HPLC system. TAC was subsequently verified by mass spectrometry and TAC glucuronide was tentatively identified by enzymatic hydrolysis and mass spectrometry of the hydrolysis product. The endogenous hormones, cortisol and cortisone were presumptively identified by cochromatography with authentic standards on two different HPLC systems and positively identified by reverse-isotope recrystallization. Other metabolites of both compounds were detected by selective enzymatic hydrolysis and HPLC. This method is rapid and reproducible with a total recovery greater than 80%.

Analysis of hydrocortisone acetate ointments and creams by high-performance liquid chromatography

High-performance liquid chromatographic (HPLC) methods for the analysis of hydrocortisone containing ointments and creams have been investigated. A method which uses a silica column and involves a minimum of sample pre-treatment has been shown to compare favourably with the triphenyltetrazolim chloride method of the British Pharmacopoeia. For hydrocortisone ointments the HPLC procedure provides results of equivalent precision and has advantages with respect to the time taken for each analysis and specificity. Application of the method to the analysis of hydrocortisone creams has been explored and the deviation between the HPLC and colorimetric method requires further investigation.

Reversed- and normal-phase high-performance liquid chromatography of 18-hydroxylated steroids and their derivatives. Comparison of selectivity, efficiency and recovery from biological samples

The chromatographic behaviour of adrenal 18-hydroxysteroids, and a series of derivatives thereof, has been studied in reversed-phase and normal-phase high-performance liquid chromatography (HPLC). Both 18-hydroxycorticosterone and 18-hydroxy-11-deoxycorticosterone exhibited a marked loss of chromatographic efficiency when separated on incompletely-covered C18 reversed-phase supports (as determined by methyl red adsorption) showed no such effect, nor was it seen when aprotic solvents, such as dioxane, were used. This phenomenon is unique among the wide range of adrenal and testicular steroids that we have studied and affords a useful test, applicable under aqueous conditions, of coverage by the alkylsilane reversed phase, a factor of considerable importance in the successful resolution of complex mixtures of adrenal steroids by reversed-phase HPLC. The retention times of the 20-methoxy, 20-ethoxy, 21-acetoxy, etiolactone, 11 beta, 18-ether and dimeric derivatives of the naturally-occurring 18-hydroxysteroids have been determined in relation to major adrenal steroids. Procedures for extraction and reversed-phase HPLC of 18-hydroxysteroids from tissues without the formation of these less polar forms, which can complicate their separation by other chromatographic techniques, are illustrated with respect to a human malignant adrenocortical tumour which caused hypermineralocorticism.