11-Oxygenated C19 Steroids Do Not Decline With Age in Women

CONTEXT

The ovaries and adrenals are sources of androgens in women. Although dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS), and testosterone (T) all decline with age, these C19 steroids correlate poorly with parameters of androgen action in postmenopausal women.

OBJECTIVE

To comprehensively compare the androgen profiles of pre- and postmenopausal women.

METHODS

We quantified 19 steroids-including DHEA; DHEAS; T; androstenedione (A4); and the following adrenal-specific 11-oxygenated C19 steroids (11oxyandrogens): 11β-hydroxytestosterone (11OHT), 11-ketotestosterone (11KT), 11β-hydroxyandrostenedione (11OHA4), and 11-ketoandrostenedione (11KA4)-using liquid chromatography-tandem mass spectrometry in morning serum obtained from 100 premenopausal (age 20 to 40 years) and 100 postmenopausal (age ≥ 60 years) women. Double immunofluorescence of 3β-hydroxysteroid dehydrogenase type 2 (HSD3B2) with cytochrome b5 (CYB5A) or sulfotransferase 2A1 (SULT2A1) was performed in normal adrenal glands obtained from eight premenopausal and eight postmenopausal women.

RESULTS

DHEA, DHEAS, A4, and T were significantly higher in pre- than in postmenopausal women (2.9, 2.8, 2.9, and 1.6-fold, respectively; P < 0.0001). In contrast, the 11-oxyandrogens did not decrease with aging, and the 11OHT/T and 11OHA4/A4 ratios showed strong positive correlations with age (r = 0.5 and 0.8, respectively; P < 0.0001). Double immunofluorescence analysis showed that with the involution of the zona reticularis in the old adrenals, the sharp zonal segregation of HSD3B2 and CYB5A becomes less distinct, and areas of HSD3B2 and CYB5A overlap are observed.

CONCLUSIONS

Unlike DHEA, DHEAS, A4, and T, the 11oxyandrogens do not decline in aging women. Structural changes within the adrenal cortex might explain the evolution of androgen profiles in aging women.

Androgens During the Reproductive Years: What Is Normal for Women?

OBJECTIVE

Whether serum androgen levels can identify women with "androgen insufficiency" or "androgen excess" is unresolved; thus, what constitutes "normal" remains uncertain. We sought to determine whether androgens, including 11-oxygenated C19 steroids, vary with age, menstrual cycle, or body mass index (BMI), during the reproductive years.

DESIGN AND SETTING

Cross-sectional study recruited from eastern Australian states.

PARTICIPANTS

A total of 588 women, aged 18 to 39 years, who were not pregnant, lactating, or using systemic hormone therapy, with regular menstrual cycles and no previous diagnosis of polycystic ovarian syndrome.

MAIN OUTCOME MEASURES

Sex steroids measured using liquid chromatography-tandem mass spectrometry.

RESULTS

Testosterone and androstenedione concentrations were significantly higher during the menstrual cycle mid- and luteal phases than in the early follicular phase, with median values across the cycle of 0.34 nmol/L (range, 0.04 to 1.01) and 1.97 nmol/L (range, 0.53 to 7.89), respectively. No cyclical variations were found in dehydroepiandrosterone (DHEA; 4.91 nmol/L; range, 0.08 to 23.51), 11-ketoandrostenedione (11KA; 7.99 nmol/L; range, 0.07 to 31.67), or 11-ketotestosterone (11KT; 1.27 nmol/L; range, 0.03 to 7.61). Overweight women had lower median testosterone (P < 0.05), DHEA (P < 0.05), and 11KA (P < 0.01) levels than normal-weight women. All C19 steroids were significantly lower (P < 0.01) in those aged 35 to 39 years than in those aged 18 to 25 years. The median 11KA/androstenedione (4.3:1) and 11KT/testosterone (3.9:1) ratios did not change with age, after adjustment for BMI and cycle stage.

CONCLUSIONS

We have demonstrated that 11KA and 11KT are stable across the menstrual cycle and make major quantitative contributions to the circulating androgen pool. All C19 androgens declined with age before menopause; hence, age-specific reference ranges are required for the interpretation of androgen levels in premenopausal women.

Seasonal changes in and effect of castration/androgen replacement on the plasma levels of five androgens in the male three-spined stickleback, Gasterosteus aculeatus L

The seasonal changes in plasma levels of the androgens 11-ketotestosterone (OT), testosterone (T), 11 beta-hydroxytestosterone (OHT), 11-ketoandrostenedione (OA), and 11 beta-hydroxyandrostenedione (OHA) were measured in the male three-spined stickleback (Gasterosteus aculeatus L). OT was the dominant plasma androgen in the breeding season in summer and was the only androgen that peaked during this period. The levels of OT correlated closely with the development of male secondary sexual characters and reproductive behavior. T and OHT were low in all seasons, whereas OHA and OA displayed the highest levels in early winter. During the postbreeding period, the time of active spermatogenesis, all measured steroids were low. Castration resulted in an almost complete loss of plasma OT and reduced T, whereas OHT, OHA, and OA were not reliably influenced. Androstenedione implants in castrated fish increased plasma T and OA implants increased plasma OT, suggesting a nontesticular site of conversion.

Steroid secretion by the postmenopausal ovary

The concentrations of certain steroids in arterial and ovarian venous blood were measured in 42 postmenopausal women undergoing hysterectomy for uterine disease. A concentration gradient across the ovary was found for testosterone in 21 women, for androstenedione in 16, for estradiol in 15, for estrone in 8, and for dehydroepiandrosterone in 3. On the basis of postualated ovarian blood blow the gradient would result in a major contribution to the blood production rate for testosterone in about 50% of women and for estradiol in less than 20%. For androstenedione, dehydroepiandrosterone, and estrone the gradients did not signify important ovarian secretion. There was no evidence for secretion of dihydrotestosterone, estrone sulfate, or dehydroepiandrosterone sulfate. There were no apparent clinical correlates to indicate in which women the ovary was secreting steroids.

Concentrations of fat and plasma 5alpha-androstenone and plasma testosterone in boars selected for rate of body weight gain and thickness of back fat during growth, sexual maturation and after mating

The levels of 5alpha-androstenone and testosterone in peripheral plasma and 5alpha-androstenone in fat collected from 18 boars selected according to thickness of back fat and rate of gain were evaluated. Sampling was started when the animals were about 100 days of age and samples were collected every 14 days until the boars were about 240 days old. The steroid profiles varied considerably between boars, although an increase in steroid levels was found in most animals with the onset of adolescence. The regression line for the level of 5alpha-androstenone in fat and the age of the animals in days was found to be y = 0.02x-1-31. High coefficients of correlation were found between the concentration of 5alpha-androstenone in peripheral plasma and fat (r = 0-78) and between levels of 5alpha-androstenone and testosterone in peripheral plasma (r = 0-64). Levels of 5alpha-androstenone in peripheral plasma above about 15 ng/ml were usually accompanied by a heavy accumulation of 5alpha-androstenone in adipose tissue. The use of four of the boars for mating resulted in increased steroid levels in peripheral plasma and fat. Significantly higher levels of 5alpha-androstenone and testosterone were found in the peripheral plasma of boars selected for fatness and a low rate of gain than in boars selected for low back-fat thickness and a high rate of gain.

Age-related Variation of Plasma Concentrations of Skatole, Androstenone, Testosterone, Oestradiol-17beta, Oestrone Sulphate, Dehydroepiandrosterone Sulphate, Triiodothyronine and IGF-1 in Six Entire Male Pigs

This study describes the age-related variation in boar taint compounds, skatole and androstenone, and testosterone, oestradiol-17 beta (E17 beta), oestrone sulphate (ES), dehydroepiandrosterone sulphate (DHEAS), triiodothyronine (T(3)) and insulin-like growth factor-1 (IGF-1) in six boars. Three pairs of littermates of crossbred entire male pigs (from three Yorkshire x Duroc dams and one Hampshire sire) were included. Blood samples were taken at the age of 9-15 weeks and thereafter at weekly intervals from the age of 20-32 weeks. Plasma concentrations of skatole, androstenone, testosterone, E17 beta, ES, DHEAS, T(3) and IGF-1 were measured. We found that skatole levels in boars increased at the age around puberty after an increase in the levels of testicular steroids. Levels of skatole were not associated with the levels of sex steroids, T(3) and IGF-1. However, the increased level of testicular steroids is probably the underlying factor needed for high skatole levels to occur although the specific mechanism leading to increased skatole levels remains unknown.

A 1-year pharmacokinetic investigation of a novel oral contraceptive containing drospirenone in healthy female volunteers

Drospirenone is a novel synthetic progestogen with a pharmacological profile similar to that of natural progesterone. It has been developed in combination with ethinylestradiol for use as an oral contraceptive (EE/DRSP, Yasmin, Schering AG, Berlin, Germany). The pharmacokinetic characteristics of drospirenone and ethinylestradiol have been assessed in healthy female volunteers over a 1-year period. During each of the 13 treatment cycles, volunteers received the combined active ingredients for 21 days, followed by a 7-day, tablet-free interval. The concentrations of the serum proteins, sex hormone binding globulin (SHBG) and corticoid binding globulin (CBG), were determined at intervals after the cessation of treatment (day 21) at the end of cycles 1, 6, 9 and 13. Drospirenone and ethinylestradiol were found to be absorbed rapidly and to reach a peak concentration in serum 1.5-2.0 h after dosing. Serum concentrations ofdrospirenone declined, with mean terminal half-lives of 30.8-32.5 h. Accumulation of both drospirenone and ethinylestradiol was observed within a treatment cycle, with a mean accumulation ratio of 3.0 for drospirenone and 2.1 for ethinylestradiol. In addition, serum drospirenone concentrations increased between treatment cycles 1 and 6, but remained steady thereafter, as reflected in the AUC values determined at the end of treatment cycles 1, 6, 9 and 13. Serum SHBG and CBG concentrations declined in a biphasic manner after cessation of treatment at the end of cycle 13, and physiological steady-state concentrations were reached within 4-6 weeks. In conclusion, drospirenone was absorbed at a similar rate as other synthetic progestogens contained in various oral contraceptives, as indicated by similar tmax values. The terminal half-life of drospirenone was intermediate between those of 19-nortestosterone derivatives like desogestrel, levonorgestrel or gestodene and C21-progestogens like cyproterone acetate. Both active ingredients of the new contraceptive EE/DRSP showed accumulation within a treatment cycle, which is also the case with other synthetic progestogen/ethinylestradiol combinations. Similar to other oral contraceptives, a reversible induction of serum SHBG and CBG concentrations was observed under EE/DRSP treatment.

Neuroactive steroids, negative affect, and nicotine dependence severity in male smokers

RATIONALE

Nicotine administration alters neuroactive steroids in rodent models, and serum levels of the neuroactive steroid DHEAS (dehydroepiandrosterone sulfate) appear to be higher in smokers. These molecules may be relevant to tobacco addiction and affective symptoms.

OBJECTIVES

This study aims to investigate DHEAS, allopregnanolone, pregnenolone, and other steroids in male smokers to determine potential associations with nicotine dependence severity and negative affect.

MATERIALS AND METHODS

Allopregnanolone and pregnenolone serum levels were determined by gas chromatography/mass spectrometry, while DHEAS and other steroid levels were determined by radioimmunoassay in 28 male smokers. Correlational analyses were performed to determine potential associations with rating measures, including the Fagerstrom Test for Nicotine Dependence (FTND), the addiction subscale of the Ikard Smoking Motivation Questionnaire (ISMQ), the craving item on the Reasons to Smoke (RTS) Questionnaire, and the negative affect and craving subscales of the Shiffman-Jarvik Withdrawal Questionnaire.

RESULTS

DHEAS levels were inversely correlated with the negative affect subscale of the Shiffman-Jarvik Withdrawal Questionnaire (r=-0.60, p=0.002) and the RTS craving item (r=-0.43, p=0.03), and tended to be inversely correlated with the FTND scores (r=-0.38, p=0.067) and the ISMQ addiction subscale (r=-0.38, p=0.059), adjusting for age. Allopregnanolone levels were positively correlated with cotinine levels (r=0.57, p=0.006); pregnenolone levels tended to be positively correlated with cotinine levels (r=0.40, p=0.066).

CONCLUSIONS

DHEAS levels were inversely correlated with negative affect and craving measures, and may predict nicotine dependence severity. Allopregnanolone levels were positively correlated with cotinine levels, suggesting that this neuroactive steroid may be upregulated in smokers. Neuroactive steroids may represent novel smoking cessation agents.

Development of a radioimmunoassay for 5 alpha-androst-16-en-3-one in pig peripheral plasma

A radioimmunoassay (RIA) for 5α-androst-16-en-3-one (5α-androstenone) in peripheral plasma from pigs has been developed. Antibodies against 5α-androstenone conjugated through C-3 to bovine serum albumin (BSA) were produced in rabbits. The antiplasma used in this study show a cross-reaction of 100% with 4,16-androstadien-3-one (androstadienone), 5.3 % with 5α-androst-16-en-3β-ol (an-β), 3.3 % with 5α-androst-16-en-3α-ol (an-α), 2.6 % with 4-androstene-3,17-dione (androstenedione) and 1.4% with 5,16-androstadien-3β-ol (andien-β).

The standard curve plotted as log picogram (pg) unlabelled 5α-androstenone against counts per minute (cpm) bound radioactive steroid was almost linear from 50 to 800 pg 5α-androstenone.

Regression analysis of the data from the accuracy study gave the curve y = 0.99 x+ 203.

The precision and sensitivity of the method were satisfactory. In plasma samples from sows and castrated male pigs the mean 5α-androstenone found was 1.1 ng/ml. In plasma samples from boars from 1.2 to 54.1 ng/ml was found.

Conversion of 11-ketoandrostenedione to 11-ketotestosterone by blood cells of six fish species

Blood cells from Baltic salmon, Salmo salar, three-spined stickleback, Gasterosteus aculeatus, eel pout, Zoarces viviparus, crucian carp, Carassius carassius, African catfish, Clarias gariepinus, and reedfish, Calamoichthys calabaricus, were incubated with tritiated 11 beta-hydroxyandrostenedione (OHA) or 11-ketoandrostenedione (OA). In all fish there was conversion of OA to 11-ketotestosterone (OT), indicating that 17 beta-hydroxysteroid dehydrogenase activity was present in the blood cells. On the other hand, OHA was not converted to 11 beta-hydroxytestosterone in any fish. The addition of serum to the incubates largely prevented the OA-OT conversion by salmon blood cells.

Testicular sulfoconjugation of the 16-androstene steroids by hydroxysteroid sulfotransferase: Its effect on the concentrations of 5α-androstenone in plasma and fat of the mature domestic boar1

This study examined the relationship between sulfoconjugation and the degree to which 5alpha-androstenone can accumulate in fat. Analysis of the unconjugated and sulfoconjugated fractions of peripheral plasma from 25 mature Yorkshire boars and testicular vein plasma from an additional 20 mature Yorkshire boars revealed that the majority of 5alpha-androstenone is present as a sulfoconjugate, reaching levels up to 69 +/- 4.3 and 72 +/- 6.2%, respectively, relative to its unconjugated form. The presence of this steroid in the sulfoconjugate fraction was confirmed by gas chromatography-mass spectrometry. Plasma concentrations of 5alpha-androstenone in the sulfoconjugate fraction were negatively correlated (r = -0.36; P < 0.01) with the concentrations of 5alpha-androstenone in fat. High concentrations of 5alpha-androstenone in the sulfate fraction were only associated with animals that had fat androstenone concentrations < 0.5 microg/g. In addition, there was a positive correlation (r = 0.31; P < 0.01) between the concentrations of unconjugated 5alpha-androstenone in plasma and 5alpha-androstenone in fat. These findings indicate that the levels of the sulfoconjugated form present in the peripheral plasma influence the accumulation of 5alpha-androstenone in fat. The specific sulfotransferase enzyme involved in sulfoconjugating these steroids was identified by incubating Leydig cells with specific sulfotransferase inhibitors for 8 h. It was discovered that the enzyme responsible for the sulfoconjugation of the 16-androstene steroids is hydroxysteroid sulfotransferase. Hydroxysteroid sulfotransferase may play a significant role in determining the levels of sulfated 16-androstene steroids present in plasma. The results of this study indicate that sulfoconjugation may serve to regulate the quantity of unconjugated 5alpha-androstenone present in the circulation and thus available for accumulation. Animals with a decreased ability to sulfoconjugate 5alpha-androstenone would have a subsequent increase in the levels of unconjugated 5alpha-androstenone in circulation, allowing for the accumulation of high levels in fat and thereby potentially leading to the development of boar taint.

Molecular cloning and regulation of porcine SULT2A1: relationship between SULT2A1 expression and sulfoconjugation of androstenone

Hydroxysteroid sulfotransferase (SULT2A1) is a key enzyme in the testicular and hepatic metabolism of 5alpha-androstenone, which is a major component of the off-odor and off-flavor in pork known as boar taint. The goals of this study were to determine the role of testicular and hepatic SULT2A1 activity on plasma 5alpha-androstenone sulfate levels, the accumulation of 5alpha-androstenone in adipose tissue, and to gain insight into the regulatory control of SULT2A1. Testicular SULT2A1 activity was negatively correlated (r = -0.57; P < 0.01) with 5alpha-androstenone concentrations in fat. The differences observed in SULT2A1 activity warranted investigation into potential genetic variation within porcine SULT2A1. The cDNA sequence of porcine Sult2A1 was determined to be > 82% homologous to the human, mouse, and rat Sult2A1 genes. A single nucleotide polymorphism was detected within the coding region of the Sult2A1 from individual testes and liver samples; however, this did not affect the amino acid sequence of the enzyme. Western blot analysis determined that animals with high concentrations of 5alpha-androstenone in fat and low SULT2A1 activity had corresponding low levels of SULT2A1 protein compared with animals with low levels of 5alpha-androstenone in fat. Real-time PCR analysis indicated that Sult2A1 mRNA was increased 2.8-fold in animals with high levels of the protein relative to animals with low levels of the protein. Furthermore, we demonstrated the positive role of the nuclear receptors constitutive androstane receptor and pregnane X receptor, as well as the possible role of farnesoid X receptor in the regulation of testicular SULT2A1 activity. Together, the results of this study suggest that differences in SULT2A1 expression can influence 5alpha-androstenone accumulation in fat.

5alpha-androstenone in peripheral plasma of pigs, diurnal variation in boars, effects of intravenous HCG administration and castration

5alpha-Androstenone2) has been measured in pig peripheral plasma by radioimmunoassay (RIA). In 73 mature boars values ranging from 1.2 ng to 54.1 ng per ml plasma with a mean value of 18.3 ng/ml and SD equal to 15.9 were found. In female pigs and castrated male pigs the mean concentrations were 2.3 ng/ml (n equal to 18) and 1.1 ng/ml (n equal to 19) with SD equal to 0.8 and SD equal to 0.3 respectively. Clear-cut diurnal variations in the concentration of 5alpha-androstenone in plasma samples from boars were not observed. Intravenous injection of HCG in boars caused an abrupt rise in the 5alpha-androstenone level reaching a maximum in 90 min. Twenty-eight hours after the injection a second peak of plasma 5alpha-androstenone was observed. Following castration of boars the level of 5alpha-androstenone in peripheral plasma fell within 4 days, to levels found in female pigs.

Serum steroid hormones including 11-ketotestosterone, 11-ketoandrostenedione, and dihydroprogesterone in juvenile and adult bonnethead sharks, Sphyrna tiburo

Previous studies in the placental viviparous bonnethead shark, Sphyrna tiburo, have correlated 17 beta-estradiol, progesterone, testosterone, and dihydrotestosterone with reproductive events in both males and females. However, several key reproductive events, including implantation, maintenance of pregnancy, and parturition, did not correlate with these four steroid hormones. Therefore, the present study investigated three steroid hormones, 11-ketotestosterone, 11-ketoandrostenedione, and dihydroprogesterone, which have demonstrably important roles in the reproductive cycles of teleosts. It was hypothesized that one or more of these three hormones would correlate with specific reproductive events in S. tiburo. Concurrently, developmental (growth and/or maturation) analyses of these three steroids plus 17 beta-estradiol, progesterone, testosterone, and dihydrotestosterone were investigated in juvenile bonnethead sharks. Serum dihydroprogesterone concentrations were highest in mature females and 11-ketotestosterone concentrations were highest in mature males. In mature females, 11-ketoandrostenedione levels were elevated from the time of mating, through six months of sperm storage and another four months of gestation. At parturition concentrations became significantly lower and remained lower until mating occurred again in another two to three months. Serum 11-ketotestosterone concentrations were the highest at implantation though not significant. In mature males, significantly elevated serum levels of dihydroprogesterone occurred in April and May, near the start of annual testicular development. During growth in males, testosterone and dihydrotestosterone increased progressively and in females, testosterone increased progressively. At maturity in males, significant increases occurred in testosterone and 11-ketotestosterone concentrations while, in females, dihydroprogesterone, 11-ketotestosterone, 17 beta-estradiol, progesterone, testosterone, and dihydrotestosterone concentrations increased. This study shows that although testosterone may be the primary androgen in the bonnethead shark, other derived androgens may have important functions in growth, maturation, and reproduction. J. Exp. Zool. 284:595-603, 1999.

Early postnatal plasma concentrations of testicular steroid hormones, pubertal development, and carcass leanness as potential indicators of boar taint in market weight intact male pigs

Testicular steroid hormone concentrations in plasma of early postnatal male pigs were compared with plasma steroid hormone concentrations and androstenone concentrations in the fat of pigs at market weight. Positive correlations were found between the concentrations of fat androstenone at market weight and the concentrations of plasma androstenone (r = 0.46; P < 0.01), estrone sulfate (r = 0.42; P < 0.01), and testosterone (r = 0.26; P < 0.05) at market weight. These correlations were not found in animals that had reached an advanced state of pubertal development as judged by high estrone sulfate concentrations in plasma. Significant correlations were observed between plasma testosterone concentrations at market weight and plasma concentrations of androstenone (r = 0.57; P < 0.05), and estrone sulfate (r = 0.49; P < 0.05) in early postnatal animals. However, concentrations of androstenone in the fat of market weight animals were not correlated with plasma concentrations of estrone sulfate, androstenone, or testosterone in early postnatal animals. Plasma concentrations of steroid hormones in early postnatal animals cannot, therefore, be used to predict the potential for boar taint in the same animals at market weight. In market weight animals, there was a negative correlation (r = -0.57; P < 0.01) between backfat thickness and concentrations of androstenone in fat. Animals were subsequently sorted according to backfat thickness into lean and fat groups of animals. There was a strong, negative correlation between back-fat thickness and androstenone concentrations in fat (r = -0.80; P < 0.01), as well as a positive correlation between plasma androstenone and concentrations of androstenone in fat (r = 0.42; P < 0.05) among the lean group of animals. This was not seen in the fat group of animals. This suggests that the accumulation of androstenone from plasma into fat may be affected by the leanness of the pig.

Analytical challenges in quantifying abiraterone with LC-MS/MS in human plasma

A method was developed and validated to quantify abiraterone in human plasma. During assay development, several analytical challenges were encountered: limited stability in patient samples, adsorption to glass, coelution with metabolites and carry-over issues. Limited stability (2 h) was found for abiraterone in fresh plasma as well as whole blood at ambient temperature. When kept at 2-8°C, abiraterone in plasma was stable for 24 h and in whole blood for 8 h. Adsorption of abiraterone to glass materials was addressed by using polypropylene throughout the method. Carry-over was reduced to acceptable limits by incorporating a third mobile phase into the gradient. The chromatographic separation of abiraterone with its multiple metabolites was addressed by using a longer analytical column and adjusting the gradient. Abiraterone was extracted by protein precipitation, separated on a C18 column with gradient elution and analyzed with tandem quadrupole mass spectrometry in positive ion mode. A stable deuterated isotope was used as the internal standard. The assay ranges from 1 to 500 ng/mL. Within- and-between-day precisions and accuracies were below 13.4% and within 95-102%. This bioanalytical method was successfully validated and applied to determine plasma concentrations of abiraterone in clinical studies and in regular patient care for patients with metastatic castration-resistant prostate cancer.

High-performance liquid chromatographic method for the determination of finasteride in human plasma at therapeutic doses

A high-performance liquid chromatographic (HPLC) method with ultraviolet detection for the determination of a novel 4-aza-steroidal inhibitor of 5 alpha-reductase in human plasma has been developed. The assay is based on a single solid-phase extraction and an efficient HPLC separation on two analytical columns in series. The assay has been fully validated and used to support Phase II and III clinical pharmacokinetic studies. The lowest limit of quantification was found to be at 1 ng/ml and allowed pharmacokinetic evaluation of the drug at doses down to 5 mg.

High-performance liquid chromatographic determination of N-(2-methyl-2-propyl)-3-oxo-4-aza-5 alpha-androst-1-ene-17 beta-carboxamide, a 4-azasteroid, in human plasma from a phase I study

A sensitive and selective high-performance liquid chromatographic method has been developed for the quantitative determination of N-(2-methyl-2-propyl)-3-oxo-4-aza-5 alpha-androst-1-ene-17 beta-carboxamide (I) in human plasma. I, a 5 alpha-reductase inhibitor and a potential therapeutic agent for benign prostatic hyperplasia, is a member of the family of compounds referred to as the 4-azasteroids. The 4-N-methyl analogue of the drug was used as the internal standard and calibration curves were developed at two levels of sensitivity to cover a large dynamic range of plasma concentrations. Drug was isolated from biological fluids with a solid-phase C18 extraction column; the analyte was further purified by adsorption and desorption from a second extraction column (CN cartridge). Evaluation of the isolation method revealed that it was reproducible and drug recoveries equalled ca. 90%. Chromatography was carried out on a C8 column (5 micron) with ultraviolet detection at 210 nm. The detection limit was ca. 10 ng/ml for I. Human plasma levels are reported for I following single-dose oral administration of 50,200 and 400 mg of drug; urinary excretion data are reported for a single volunteer given 400 mg of I.