High-pressure liquid chromatography of steroids

HPLC–RIA analysis of steroid hormone profile in a virilizing stromal tumor of the ovary

The pathological steroid biosynthesis of a virilizing ovarian tumor was examined via high performance liquid chromatography-radioimmunoassay (HPLC-RIA) determination of the intratissular steroid concentrations. Sex cord-stromal tumor of the ovary was obtained surgically from an 18-year-old female patient with extremely high androst-4-ene-3,17-dione (4-en-dione) and testosterone (Test) blood serum levels. The tissue specimen was extracted with ethyl acetate and the extract was then purified on a C18 mini-column with methanol-water eluents. Steroids were isolated by reversed-phase HPLC on a C18 silica gel column with 51%, 55% and 64% v/v methanol-water eluents. Steroids in the collected eluent fractions were detected by the radioactivity of tritiated internal standards and then quantified by specific RIAs. In the tumor specimen, very high 17alpha-hydroxyprogesterone (17-OH-Prog; 6300 fmol/g), dehydro-epiandrosterone (2870 fmol/g), androst-4-ene-3,17-dione (3000 fmol/g), testosterone (5700 fmol/g) concentrations, and less progesterone (PROG; 320 fmol/g) and androst-5-ene-3beta,17beta-diol (5-en-diol; 320 fmol/g), were determined. Tissue levels of 5alpha-dihydrotestosterone (DHT), 5alpha-androstane-3alpha,17beta-diol (3alpha-diol), 5alpha-androstane-3beta,17beta-diol (3beta-diol), and 17beta-estradiol were found to be 71, 20, 28, and 12 fmol/g, respectively. Steroid profile analysis verified a pathological steroid biosynthesis in the ovarian tumor and suggested that the 17alpha-hydroxylase (17alpha-H), 17,20-lyase (17,20-L), and 3beta-hydroxysteroid dehydrogenase/Delta5-4-isomerase (Delta5-3beta-HSD) activities were particularly elevated in this tumorous tissue. Present data demonstrate that the analysis of intratissular steroid profile by a HPLC-RIA method may valuably contribute to the steroidal pathophysiology of endocrine tumors.

Exogenous steroid substrate modifies the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on estradiol production of human luteinized granulosa cells in vitro

The in vitro effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on steroid metabolism in human luteinized granulosa cells (hLGC) have been summarized as a decreased estradiol (E(2)) production without altering either E(2) metabolism or cytochrome P450 aromatase activity. In the present study, hLGC were used to analyze the fate of different substrates for cytochrome P450 17alpha-hydroxylase/17,20-lyase (P450(c17)) in the presence or absence of TCDD. Human LGCs were plated directly on plastic culture dishes in medium supplemented with 2 IU/ml of hCG. TCDD (10 nM) or its solvent was added directly to the cells at the time of medium change, every 48 h for 8 days. The objective of the experiment was to test the hypothesis that exogenous steroid, substrate for P450(c17), would reduce the TCDD effects on E(2) synthesis. With dehydroepiandrosterone (DHEA) (a P450(c17) product), a dose-related increase in E(2) production was observed and the effect of TCDD on lowering E(2) production disappeared. In contrast, with increasing doses, up to 10 micro M, of pregnenolone (P(5)), no change in E(2) production was observed. However, 17alpha-hydroxypregnenolone (17P(5)) at 10 micro M produced a modest but significant increase in the E(2) production. Treatments with P(5) and 17P(5) did not alter the effect of TCDD on E(2) production. Radiolabeled substrate utilization by hLGC suggests that the principal metabolic pathway for Delta5 substrates is the conversion to a Delta4 product probably by a very active 3beta-hydroxysteroid dehydrogenase. We conclude that estrogen production by hLGC is limited at the level of lyase activity. Thus, these data suggest that the most likely target for the TCDD-induced inhibition of estrogen synthesis by hLGC is the 17,20-lyase activity of the P450(c17) enzyme complex.

Analysis of steroidal lipids by gas and liquid chromatography

This article describes the most commonly used procedures and recent laboratory methodologies using gas and liquid chromatography developed for separation and quantitation of non-saponifiable steroidal lipids from clinical (human) studies, edible fats and oils or fatty foods.

Simultaneous determination of urinary free cortisol and 6 beta-hydroxycortisol by high-performance liquid chromatography to measure human CYP3A activity

The ratio of the hydrophilic metabolite 6 beta-hydroxycortisol to its parent compound cortisol has recently been demonstrated to be a specific marker for human CYP3A oxygenase activity. We have developed a sensitive and simple single-run high-performance liquid chromatographic method for the quantification of urinary free cortisol and 6 beta-hydroxycortisol using dexamethasone as internal standard. The urine samples (1 ml) are applied to Sep-Pak cartridges, which are washed with water and eluted with ethyl acetate-diethyl ether (4:1, v/v). The organic extracts are washed sequentially with alkaline and acidic solutions saturated with sodium sulfate and subsequently concentrated to dryness. After reconstitution in ethanolic water, the samples are analyzed on a reversed-phase gradient system using ultraviolet absorbance detection at 254 nm. The within- and between-day coefficients of variation (C.V.) for the assay where both in the range of 5-10%. The reference interval for the 6 beta-hydroxycortisol/cortisol ratio of eleven healthy non-smoking subjects was 2.77-26.88 with an average of 10.09 +/- 6.89 (S.D.). The method constitutes an improvement over previous methods and is suitable for routine assessment of the 6 beta-hydroxycortisol/cortisol ratio requiring only 1 ml of urine or less.

Reversed phase high performance liquid chromatographic separation of hydroxy steroidal unsaturated esters and their hemisuccinates

The high performance liquid chromatographic (HPLC) separation and identification of 12 isomeric and/or highly chemically related steroids with an unsaturated ester moiety at position 17 beta has been achieved. The main stereochemical features of the steroid skeleton cover 3 alpha/beta, 5 alpha/beta or delta, and 20 E/Z, bearing the alcohol or hemisuccinate group at the 3 position. The isocratic reversed phase C18 HPLC separation employed ethanol, methanol and its mixtures with water or 0.01 M phosphoric acid as the mobile phase. The best separation of the respective alcohols from their hemisuccinates has been achieved with 20% of aqueous phase content. The best separation among isomeric or related steroids has been achieved with methanol:water 8:2 and 85:15 and similar systems containing phosphoric acid.

Hypertensive congenital adrenal enzymatic defects detected by high-performance liquid chromatography of corticosteroids

The simultaneous measurement of the adrenal deoxycorticosterone (DOC), 18-OH-DOC, corticosterone (B), 18-OH-B, 11-deoxycortisol (S) and cortisol (F) present in human plasma in cases of adrenal dysfunction was accomplished using a high-performance liquid chromatographic (HPLC) system with a UV detector and with a radioimmunoassay (RIA). After a solid-phase extraction, plasma samples were separated by HPLC using a gradient of water-acetonitrile-ethanol on a radial compressed reversed-phase column. In a 70-min cycle, a complete separation of adrenal steroids was accomplished. The UV detector allowed direct measurement of F in each plasma sample while in selected cases B and S were directly determined. It was therefore possible quickly to identify patients with hypertensive congenital adrenal enzymatic defects with this method: the 17-alpha-hydroxylase deficiency characterized by the absence of measurable levels of F with an evident peak corresponding to B and the 11-beta-hydroxylase deficiency in which high levels of S without F are detected. The RIA of DOC, B, 18-OH-DOC and 18-OH-B complete the characterization of the adrenal defect. Therefore, with this HPLC method it is possible to recognize the major hypertensive adrenal enzymatic deficiencies such as the defect of 17-alpha-hydroxylase or 11-beta-hydroxylase. With "RIA" detectors an almost complete spectrum of adrenal steroid secretion can be obtained.

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.

Comparison of the chromatographic properties of sterols, select additional steroids and triterpenoids: gravity-flow column liquid chromatography, thin-layer chromatography, gas-liquid chromatography and high-performance liquid chromatography

The chromatographic properties of approximately 100 sterols, select steroids of plant origin (sapogenins and steroidal alkaloids) and triterpenoids has been evaluated in this laboratory by monitoring their elution characteristics in adsorption (gravity column and thin-layer methods with and without the addition of silver nitrates), gas and reversed-phase high-performance liquid chromatography. The utility of each methodology to act in one or another chromatographic mode-separation, radio-chemical purification, quantitation and structural elucidation, is discussed. The importance of the tilt of the -OH group at C-3 as well as the polarity, size, an shape of the rest of the molecule as it effects the hydrogen-bonding ability of the -OH group is demonstrated through changes in chromatographic behavior that result from the step-wise introduction of double bonds, methyl, bromo, oxygen, nitrogen and cyclopropyl groups into 5 alpha-cholestanol. An independent aid in the structure identification and quantitation of the compounds was use of a multiple-wavelength diode array detector in which different wavelengths of the UV spectrum (200-400 nm) were simultaneously monitored following passage of the sample through a reversed-phase C18 column.

Selective determination of urinary free cortisol by liquid chromatography after solid-state extraction

We have developed a selective and precise high-performance liquid chromatographic method for urinary free cortisol with an improved and efficient sample clean-up using C18 Sep-Pak cartridges. The urine sample (2 ml), with 11-deoxycortisol as internal standard, is applied to the Sep-Pak, which is then sequentially washed with acetone-water (1:4, v/v), water and hexane. Cortisol is eluted with diethyl ether, evaporated to dryness and redissolved in 2 ml of water. The wash cycle is repeated once using the same Sep-Pak cartridge. This double extraction greatly improves sample clean-up and allows modification of the mobile phase (tetrahydrofuran-methanol-water) so that cortisol is rapidly eluted as a single well resolved peak at 13 min. Chromatography is performed isocratically on a reversed-phase column with detection at 254 nm. Detection limits for urinary free cortisol by this procedure were two or three times lower than those obtained with two commercial radioimmunoassay kits. The chromatographic method was used successfully in the diagnosis of patients with hypercortisolism and Cushing's syndrome.

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.

A multi-residue TLC screening procedure for anabolic oestrogens and detection of oestradiol, DES or zeranol in chicken muscle tissue extracts

A multi-residue HETLC (High Efficiency Thin Layer Chromatography) screening procedure for 17 beta-oestradiol, diethylstilboesterol (DES), zearalanol (zeranol), zearalenone and their metabolites oestrone, zearalanone, and zearalenol is described. The anabolic oestrogens were analyzed on HETLC plates coated with silica gel and were developed in methylene chloride:methanol: 2-propanol (97:1:2 v/v). The spots were visualized by exposure to iodine vapours and subsequently sprayed with 1% starch solution. Analysis of standards by HETLC at 4 degrees C as a seven-component mixture showed six discrete bands with mean Rfs of 0.37 (oestrone), 0.35 (zearalanone and zearalenone), 0.26 (t-DES), 0.23 (oestradiol), 0.17 (zearalenol and zearalanol), and 0.15 (c-DES). Chicken muscle tissues (1, 2.5, or 5 g) were extracted with 95% acetone. Extracts were then fortified with 50-250 ng each of the anabolic oestrogens, purified in alumina and ion-exchange columns and analyzed by HETLC. Oestradiol, zeranol or DES in fortified tissue extracts were clearly detected when an equivalent of 4 ng were analyzed by HETLC after purification in alumina and ion-exchange columns. The intensity of their bands suggested near quantitative recovery when compared to intensity of bands of known amounts of standards. The described extraction, purification, and TLC procedures can be used to screen these oestrogens at low ppb amounts in chicken muscle tissues and should be applicable to screen tissues of cattle and sheep.

Reversed-phase high-performance liquid chromatographic separation of steroids with the beta-crotonate side chain

An isocratic high-performance liquid chromatographic separation of some ethyl 3-stereoidyl crotonates [ethyl-24-nor-20(22)-cholen-23-oate derivatives] was developed. The separations were achieved by reversed-phase chromatography (Separon Si C18) using methanol, methanol-water, methanol-0.1 M formic acid and ethanol-0.01 M aqueous phosphoric acid mixtures as mobile phases. The steroidal crotonates were detected at 230 and 240 nm.

Correlation between the molecular structure of cardiac glycosides, steroid hormones and carbohydrates and their retention in high-performance liquid chromatography

Cardiac glycoside molecules and other molecules can be thought as consisting of a number of functional groups that make individual average contributions to the overall retention. To evaluate these contributions it was necessary to solve a system of linear equations by the last-squares method for a number of cardiac glycosides and steroid hormones, the retention volumes of which were determined under standard conditions. Experimental values of the logarithm of retention volumes are compared with calculated values, ln VR' = sigma niai, where ai = ln (VR')i is the contribution to the retention of group i and ni is the number of functional groups in a molecule. Such a comparison shows that these values are in good agreement and the method may be used to evaluate the retentions of cardiac glycosides, steroid hormones and carbohydrates. The correlation of biological activity of cardiac glycosides and the logarithm of retention volumes is expressed by a linear equation, the coefficients of which have been determined. This equation shows that biological activity is related to the hydrophilic-hydrophobic properties of cardiac glycosides and consequently with the transport of these compounds to the receptor.

Determination of serum delta 5-3 beta-hydroxysteroid sulphates by combined high-performance liquid chromatography and immobilized 3 beta,17 beta-hydroxysteroid dehydrogenase in column form

We studied the use of an immobilized enzyme, covalently bound to aminopropyl-CPG, in the analysis of individual delta 5-3 beta-hydroxysteroid sulphates. A microcolumn with immobilized 3 beta,17 beta-hydroxysteroid dehydrogenase was prepared and used together with high-performance liquid chromatography (HPLC). The reduced nicotinamide-adenine dinucleotide produced from delta 5-3 beta-hydroxysteroids by this enzyme was fluorimetrically determined. The immobilized enzyme was sufficiently stable for at least one month or for 180 tests when used repeatedly. A clinical trial demonstrated that this HPLC-immobilized enzyme method is superior to the soluble enzyme method, giving reliable and reproducible results at a low cost.

Naturally occurring conjugated bile acids, measured by high-performance liquid chromatography, in human, dog, and rabbit bile

The aim of this study was to determine the biliary pattern of conjugated bile acids after stimulation of their enterohepatic circulation. Conjugated bile acids were separated by reversed-phase ion-pair chromatography without prior derivatization. A MicroPak SP-C18-IP-4 column was used as non-polar matrix, and an ionic alkyl compound, tetrabutylammonium phosphate, was added to the mobile phase, which was a mixture of acetonitrile and water. Quantification was made by UV absorption at 210 nm with external standardization. In fourteen human patients with external biliary drainage after papillotomy there was preferential glycine conjugation. The mean values were 36.5% for glycocholic acid, 33% for glycochenodeoxycholic acid, and 10.0% for glycodeoxycholic acid. Only 15.2% of the biliary bile acids were taurine metabolites. Conjugates of ursodeoxycholic acid were below 2.1%. In most cases, conjugated lithocholic acid was not detected. Within 4 h after ingestion of a standardized meal there were no significant changes in the biliary bile acid pattern. In four dogs (beagles), glycine-conjugated bile acids were lacking. The mean values were 74.3% for taurocholic acid, 14.9% for taurodeoxycholic acid, and 5.3% for taurochenodeoxycholic acid. In six rabbits, 87.4% of biliary bile acids was identified as glycodeoxycholic acid and 5.3% as glycocholic acid. In conscious dogs, as well as in rabbits, the stimulation of biliary secretion by cholecystokinin and/or secretin had no effect on the biliary bile acid spectrum. Evidently, there is a difference in the biliary composition of conjugated bile acids between humans, dogs, and rabbits. Because of the different physicochemical behaviour of glycine- and taurine-conjugated bile salts, it seems difficult to compare the therapeutic effect of gallstone dissolution in various species.

Determination of sterol and triterpene alcohol acetates in natural products by reversed-phase liquid chromatography and gas chromatography-mass spectrometry

A partial separation of nine sterol acetates and seven triterpene alcohol acetates by reversed-phase liquid chromatography is described. Good results are obtained using acetonitrile-water (90:10, v/v) as mobile phase with an UV detector at 205 nm. The variation in sterol sensitivity shows that this technique is not suitable for quantitative analyses. A combination of this technique for the fractionation of the natural sterol mixture, gas-liquid chromatography for quantitation and gas chromatography-mass spectrometry for identification is necessary for the determination of sterol compounds contained in natural products. An example of the separation, identification and quantitation of sterol acetates from sunflower seed oil is given.

Pharmacokinetics of 19-nortestosterone esters in normal men

A reliable method for the isolation of 19-nortestosterone (NT), testosterone (T) and dihydrotestosterone (DHT) by high-performance liquid chromatography (HPLC) and quantitation of the individual steroids by radioimmunoassays is described. The method was used to measure serum concentrations of NT, T and DHT in a pharmacokinetic study and in a clinical trial for male fertility control. Following intramuscular injection of either 50 mg 19-nortestosterone-3-(p-hexoxyphenyl)-propionate (NP) or 50 mg 19-nortestosterone-decanoate (ND) serum NT increased rapidly to maximal concentrations of 4.6 +/- 3.2 and 2.0 +/- 1.3 nmol/l (+/-SD), respectively, in the 6 volunteers. The half-life time was 8 days for ND and 21 days for NP. Based on these findings a clinical trial with NP was performed. NP was given to 5 healthy men in doses of 100 mg/week for the first 3 weeks followed by 200 mg/week for 10 further weeks. Serum NT levels increased gradually and maximal concentrations were reached in the 13th treatment week (20.2 +/- 3.4 nmol/l). Measurable amounts of NT were detectable for 19 weeks after the last injection. The study shows that NT accumulates under this treatment regime and wider spacing of the injection intervals may be possible in future trials.

High-performance liquid chromatography of sterols: yeast sterols

It is evident that the high-pressure liquid chromatograph is an excellent tool for studying sterol metabolism. As noted in the text, the individual effects of unsaturations and alkyl groups on reverse phase elution volumes cannot be extrapolated to predict quantitative effects of multiple functional groups. The mechanism(s) of retention seems more complex than can be explained simply by polarity or hydrophobicity. Since the molecular location of these functional moieties seems critical, retention and separation of sterols may involve specific structural configurations and hence specific interactions with the stationary phase material. The association we have drawn between polarity and HPLC elution may indeed be a secondary effect of another phenomenon. Future studies may unveil the true mechanism(s) of HPLC retention and separation, and allow for the construction of HPLC systems which will separate all isomeric combinations of sterols at the analytical level. The simplicity, rapidity, and reproducibility of these methods make the coupled technique very useful for investigating sterol metabolism. Application of this technique to analyzing putative sterol mutants, purifying sterols for auxotrophic feeding, and analyzing the metabolism of supplemented sterols in auxotrophs provides for significant advances in membrane physiology.

Clinical applications of the rapid high-performance liquid chromatographic determination of serum cortisol

We report a rapid and specific analytical method for the measurement of serum cortisol by reversed-phase high-performance liquid chromatography (HPLC). The method allows the diagnostic measurement of cortisol in emergency clinical circumstances of glucocorticoid deficiency or excess. Results obtained by HPLC are comparable to those by radioimmunoassay. The lower limit of sensitivity is 6 ng cortisol per ml of serum.

Reversed-phase high-performance liquid chromatography for the determination of steroid hormones in oral contraceptives

Reversed-phase high-performance liquid chromatography with UV detection is studied for the determination of both progestogenic and oestrogenic components of oral contraceptive formulations. The applicability of the assay is demonstrated for a number of different progestogen-oestrogen combinations in both conventional tablet and novel "paper" formulations. The results show that the method developed is a versatile technique for the routine assay of these pharmaceutical formulations.

Digoxin and metabolites in urine: a derivatization--high-performance liquid chromatographic method capable of quantitating individual epimers of dihydrodigoxin

A high-performance liquid chromatographic method is described for the determination of digoxigenin, digoxigenin monodigitoxoside, digoxigenin bis-digitoxoside, digoxin, and dihydrodigoxin as the 3,5-dinitrobenzoyl esters. The method is applied to a 10 ml urine sample by adding digitoxigenin as internal standard, extracting with methylene chloride, derivatizing with 3,5-dinitrobenzoyl chloride in pyridine, chromatographing with a normal-phase system and detecting at 254 nm. Derivatized digoxigenin, digoxigenin mono- and bis-digitoxoside, and digoxin each yielded one symmetrical peak with the limit of sensitivity of the method being approximately 100 ng/ml. Analysis of a commercially obtained sample of dihydrodigoxin resulted in two well-separated, symmetrical peaks that represent the two epimers of derivatized dihydrodigoxin. Data indicate rapid and complete esterification of all primary and secondary alcohol moieties in the various molecules and the derivatives are shown to be stable in chloroform for at least four days. The procedure appears to be suitable for metabolic investigations and as a prototype for future analytical developments.

A comparison of three methods of hydrolysis for estrogen conjugates

The efficiencies for estrogen conjugate hydrolysis were compared between enzyme hydrolysis, acid solvolysis and a new method, ammonolysis. Samples included: 1) crystalline 1,3,5(10)-estratriene-3, 17 beta-diol disulfate (estradiol 3,17-disulfate), 2) squirrel monkey urine collected following an intravenous injection of [2,4,6,7-H] 1,3,5(10)-estratriene-3,17 beta-diol (estradiol) and 3) a pool of human pregnancy urine. Ammonolysis demonstrated a significant increase over the other techniques in "free" estrogen yields, specifically, from estradiol 3,17-disulfate.

Measurement of conjugated bile acids by ion-pair high-performance liquid chromatography

Vhe quantitatively most important conjugated bile acids in man were separated by reversed-phase ion-pair chromatography without prior derivatization. As non-polar matrix an Ultrasphere I.P. column (C18) was used, and an ionic alkyl compound, tetrabutylammonium phosphate, was added to the mobile phase, which was a mixture of acetonitrile and water. Under these conditions, the glycine and taurine conjugates of cholic acid, chenodeoxycholic acid and deoxycholic acid were separated within 15 min. At 214 nm, the minimum measurable concentration was 1.3-2.0 nmol/ml. The average recovery from bile was 94%. In ten patients with biliary drainage an average of 79.5% of the bile acids were glycine conjugates.

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 steroidal estrogens and their major unconjugated metabolites by high performance liquid chromatography

A high performance liquid chromatographic method is described for the rapid, non-destructive separation of a number of physiologically important steroidal estrogens, including the labile catechol estrogens. This procedures uses a "Diol" column and gradient elution to separate in a single run, estrogens ranging from 2-methoxy estrone, one of the least polar C18 steroids, to estriol, one of the most polar. Simpler, isocratic conditions, are provided for the separation of estrogens of similar polarity. A semi-preparative column of similar composition was used for the purification of samples containing 25 to 50 mg of individual steroids.