Exploring the Impact of the Microbiome on Neuroactive Steroid Levels in Germ-Free Animals

Steroid hormones are essential biomolecules for human physiology as they modulate the endocrine system, nervous function and behaviour. Recent studies have shown that the gut microbiota is directly involved in the production and metabolism of steroid hormones in the periphery. However, the influence of the gut microbiota on levels of steroids acting and present in the brain (i.e., neuroactive steroids) is not fully understood. Therefore, using liquid chromatography–tandem mass spectrometry, we assessed the levels of several neuroactive steroids in various brain areas and the plasma of germ-free (GF) male mice and conventionally colonized controls. The data obtained indicate an increase in allopregnanolone levels associated with a decrease in those of 5α-androstane-3α, 17β-diol (3α-diol) in the plasma of GF mice. Moreover, an increase of dihydroprogesterone and isoallopregnanolone in the hippocampus, cerebellum, and cerebral cortex was also reported. Changes in dihydrotestosterone and 3α-diol levels were also observed in the hippocampus of GF mice. In addition, an increase in dehydroepiandrosterone was associated with a decrease in testosterone levels in the hypothalamus of GF mice. Our findings suggest that the absence of microbes affects the neuroactive steroids in the periphery and the brain, supporting the evidence of a microbiota-mediated modulation of neuroendocrine pathways involved in preserving host brain functioning.

Interaction of sex steroid hormones and obesity on insulin resistance and type 2 diabetes in men: the Third National Health and Nutrition Examination Survey

AIMS

We examined interaction of sex steroid hormones and obesity with regard to insulin resistance (IR) and type 2 diabetes (T2D) by using nationally representative data from the US.

METHODS

Data of 1461 men aged ≥20years who participated in the Third National Health and Nutrition Examination Survey were analyzed. Multiplicative interaction was calculated by cross-product interaction terms in multivariable logistic regression models. Additive interaction was assessed by the relative excess risk due to interaction (RERI).

RESULTS

After adjusting for demographic and lifestyle covariates, the odds of IR were greatest among obese men with low free testosterone and high androstanediol glucuronide. Multiplicative interactions for total testosterone, free testosterone, and free estradiol index (FEI) were statistically significant with central obesity but not with overweight and obesity regarding to T2D (P<0.05). Significant additive interactions with obesity or central obesity were detected for total testosterone (RERI=2.75, 95% CI=0.92,4.59), SHBG (RERI=5.71, 95% CI=0.77,10.64), and FEI (RERI=-9.96, 95% CI=-19.18,-0.74) with regard to IR, beta-cell dysfunction, and T2D.

CONCLUSIONS

Our findings add to the evidence suggesting that low testosterone and high estradiol may be associated greater risks of IR and T2D by interacting with overall and central obesity in adult men.

Profiling Neuroactive Steroid Levels After Traumatic Brain Injury in Male Mice

The incidence of traumatic brain injuries (TBIs) in humans has rapidly increased in the last ten years. The most common causes are falls and car accidents. Approximately 80 000-90 000 persons per year will suffer some permanent disability as a result of the lesion, and one of the most common symptoms is the decline of hormone levels, also known as post-TBI hormonal deficiency syndrome. This issue has become more and more important, and many studies have focused on shedding some light on it. The hormonal decline affects not only gonadal steroid hormones but also neuroactive steroids, which play an important role in TBI recovery by neuroprotective and neurotrophic actions. The present work used an adolescent close-head murine model to analyze brain and plasma neurosteroid level changes after TBI and to establish correlations with edema and neurological impairments, 2 of the hallmarks of TBI. Our results showed changes in brain pregnenolone, testosterone, dihydrotestosterone (DHT), and 3α-diol levels whereas in plasma, the changes were present in progesterone, DHT, 3α-diol, and 3β-diol. Within them, pregnenolone, progesterone, DHT, and 3α-diol levels positively correlated with edema formation and neurological score, whereas testosterone inversely correlated with these 2 variables. These findings suggest that changes in the brain levels of some neuroactive steroids may contribute to the alterations in brain function caused by the lesion and that plasma levels of some neuroactive steroids could be good candidates of blood markers to predict TBI outcome.

Synthesis of 5α-androstane-3α,17β-diol 17-O-glucuronide histaminyl conjugate for immunoassays

Simple method of preparation of 5α-androstane-3α,17β-diol 17-O-glucuronide N-histaminyl amide was developed for the construction of immunoanalytical kit. Improved method of glucuronide derivative synthesis was used, followed by hydroxybenzotriazole-dicyclohexylcarbodiimide coupling with histamine.

Neuroprotective Effect of Progesterone in MPTP-Treated Male Mice

BACKGROUND

Numerous studies have reported on the neuroprotective activity of estradiol, whereas the effect of the other ovarian steroid, progesterone, is much less documented.

METHODS

This study sought to investigate neuroprotection with a low dose of progesterone (1 µg) in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated male mice to model Parkinson's disease and compare it to the effect of this steroid in intact mice (experiment 1). We also investigated if high doses of progesterone could protect dopaminergic neurons already exposed to MPTP (experiment 2). We measured progesterone effects on various dopaminergic markers [dopamine and its metabolites, dopamine transporter (DAT) and vesicular monoamine transporter 2 (VMAT2)] and on neuroactive steroids in both plasma and the brain.

RESULTS

For experiment 1, our results showed that progesterone completely prevented the effect of MPTP toxicity on dopamine concentrations, on the increase in the 3-methoxytyramine/dopamine ratio, as well as on VMAT2-specific binding in the striatum and the substantia nigra. Progesterone decreased MPTP effects on 3,4-dihydroxyphenylacetic acid concentrations and DAT-specific binding in the lateral part of the anterior striatum and in the middle striatum (medial and lateral parts). Progesterone treatment of intact mice had no effect on the markers investigated. For experiment 2, measures of dopaminergic markers in the striatum showed that 8 mg/kg of progesterone was the most effective dose to reduce MPTP effects, and more limited effects were observed with 16 mg/kg. We found that progesterone treatment increases the levels of brain progesterone itself as well as of its metabolites.

CONCLUSION

Our result showed that progesterone has neuroprotective effects on dopaminergic neurons in MPTP-treated male mice.

Circulating total testosterone and PSA concentrations in a nationally representative sample of men without a diagnosis of prostate cancer

BACKGROUND

The association between serum sex steroid hormones and PSA in a general population has not been described.

METHODS

Included were 378 men aged 40-85 years who participated in the National Health and Nutrition Examination Survey in 2001-2004, who did not have a prostate cancer diagnosis, and had not had a recent biopsy, rectal examination, cystoscopy, or prostate infection or inflammation. Serum total PSA, total testosterone, androstanediol glucuronide (3α-diol-G), estradiol, and sex hormone binding globulin (SHBG) concentrations were previously measured. Free testosterone was estimated by mass action. We applied sampling weights and calculated geometric mean PSA concentration by hormone quintiles adjusting for age and race/ethnicity, and also for body mass index, waist circumference, smoking, diabetes, and mutually for hormones. We estimated the OR of PSA ≥2.5 ng/ml per hormone quintile using logistic regression.

RESULTS

Geometric mean PSA increased across testosterone quintiles after age and race/ethnicity (Q1: 0.80, Q5: 1.14 ng/ml; P-trend = 0.002) and multivariable (Q1: 0.79, Q5: 1.16 ng/ml; P-trend = 0.02) adjustment; patterns were similar for free testosterone and 3α-diol-G. SHBG was inversely associated with PSA only after multivariable adjustment (Q1: 1.32, Q5: 0.82 nmol/L; P-trend = 0.01). Estradiol and PSA were not associated. The OR of PSA ≥2.5 ng/ml was 1.54 (95% CI 1.18-2.01) per testosterone quintile after age and race/ethnicity adjustment, and 1.78 (95% CI 1.16-2.73) after multivariable adjustment.

CONCLUSIONS

In this nationally representative sample, men with higher testosterone had higher PSA even after taking into account other hormones and modifiable factors. Men with higher SHBG had lower PSA, but only after multivariable adjustment.

A rapid and sensitive UPLC-MS/MS method for the simultaneous quantification of serum androsterone glucuronide, etiocholanolone glucuronide, and androstan-3α, 17β diol 17-glucuronide in postmenopausal women

Quantification of steroidal glucuronide conjugates by the indirect methods of immunoassay and GC-MS/MS may underestimate some conjugates since hydrolysis is needed in sample processing. In the present work, a sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the simultaneous direct quantification of androsterone glucuronide, etiocholanolone glucuronide, and androstan-3α, 17β diol 17-glucuronide in postmenopausal women's serum. The quantification limits are 0.1ng/mL for 3α-diol-17G and 4ng/mL for both ADT-G and Etio-G, respectively, with an extraction from 200μL serum while the total run time is less than 6min for all three glucuronides. In this method, solid phase extraction is used for sample preparation. The assay has been validated in compliance with EndoCeutics SOPs and FDA guidelines for bioanalytical method development and validation. The recovery of glucuronides in stripped serum is consistent with that in unstripped serum, where the average difference in stripped and unstripped is less than 10%. A linear regression model fits well the standard curves of all three compounds with R≥0.99 where the weighting factor is 1/X. Interday accuracy and CV for all levels of QCs are within the range of 15% in both stripped and unstripped serum while all calibration curves are within the range of 6% except for LLOQs, which are within the range of 9%. Other parameters have also been assessed such as selectivity, matrix, lipemic and hemolysis effects as well as stabilities in solution and matrix. Incurred sample reanalysis has been performed with a result of over 93% within 20% of the original values. This reliable, sensitive and fast method is ready for large-scale clinical sample assays.

Neurosteroid 3α-androstanediol efficiently counteracts paclitaxel-induced peripheral neuropathy and painful symptoms

Painful peripheral neuropathy belongs to major side-effects limiting cancer chemotherapy. Paclitaxel, widely used to treat several cancers, induces neurological symptoms including burning pain, allodynia, hyperalgesia and numbness. Therefore, identification of drugs that may effectively counteract paclitaxel-induced neuropathic symptoms is crucial. Here, we combined histopathological, neurochemical, behavioral and electrophysiological methods to investigate the natural neurosteroid 3α-androstanediol (3α-DIOL) ability to counteract paclitaxel-evoked peripheral nerve tissue damages and neurological symptoms. Prophylactic or corrective 3α-DIOL treatment (4 mg/kg/2days) prevented or suppressed PAC-evoked heat-thermal hyperalgesia, cold-allodynia and mechanical allodynia/hyperalgesia, by reversing to normal, decreased thermal and mechanical pain thresholds of PAC-treated rats. Electrophysiological studies demonstrated that 3α-DIOL restored control values of nerve conduction velocity and action potential peak amplitude significantly altered by PAC-treatment. 3α-DIOL also repaired PAC-induced nerve damages by restoring normal neurofilament-200 level in peripheral axons and control amount of 2’,3’-cyclic-nucleotide-3’-phosphodiesterase in myelin sheaths. Decreased density of intraepidermal nerve fibers evoked by PAC-therapy was also counteracted by 3α-DIOL treatment. More importantly, 3α-DIOL beneficial effects were not sedation-dependent but resulted from its neuroprotective ability, nerve tissue repairing capacity and long-term analgesic action. Altogether, our results showing that 3α-DIOL efficiently counteracted PAC-evoked painful symptoms, also offer interesting possibilities to develop neurosteroid-based strategies against chemotherapy-induced peripheral neuropathy. This article shows that the prophylactic or corrective treatment with 3α-androstanediol prevents or suppresses PAC-evoked painful symptoms and peripheral nerve dysfunctions in rats. The data suggest that 3α-androstanediol-based therapy may constitute an efficient strategy to explore in humans for the eradication of chemotherapy-induced peripheral neuropathy.

[The antiepileptic role of 3α-androstanediol on the epileptic rats induced by pentylenetetrazole]

The influence of 3α-androstanediol (3α-diol) on twitch and electroencephalogram (EEG) of the epileptic rats induced by pentylenetetrazole (PTZ) has been observed in this experiment in order to comprehensively explore the role of 3α-diol on epileptic attack from the aspects of behavior and EEG. Thirty-two male Sprague-Dawley rats were evenly and randomly divided into 4 groups: the normal and supplied with oil epileptic (N+oil+PTZ) group, the normal and supplied with 3α-diol epileptic (N+3α-diol+PTZ) group, the gonadectomized and supplied with oil epileptic (GDX+oil+PTZ) group and the gonadectomized and supplied with 3α-diol epileptic (GDX+3α-diol+PTZ) group. The changes of the behavior and EEG of epileptic rats in every group were recorded and analyzed. The results of behavior observation showed that the latency to clonic seizure and tonic-clonic seizure was shortened and the number of tonic-clonic seizure was increased significantly in the GDX+oil+PTZ group in comparison with N+oil+PTZ group (P < 0.05); comparing GDX+3α-diol+PTZ group with GDX+oil+PTZ group, or N+3α-diol+PTZ group with N+oil+PTZ group, we found that the latency to clonic seizure and tonic-clonic seizure became prolonged significantly, and the number of clonic seizure and tonic-clonic seizure was decreased significantly (P < 0.05). The results of EEG showed that the latency to epileptic waves was cut and the number of epileptic waves was augmented significantly in the GDX+oil+PTZ group in comparison with N+oil+PTZ group (P < 0.05); comparing GDX+3α-diol+PTZ group with GDX+oil+PTZ group, or N+3α-diol+PTZ group with N+oil+PTZ group, we found that the latency to epileptic waves became lengthened significantly, the number of epileptic waves was reduced significantly and the percentage of change of TP (total power of spectrum) was lessened significantly (P < 0.05). These results indicate that 3α-diol has an antiepileptic activity in the gonadectomized and normal epileptic rats.

Testosterone responses to intensive interval versus steady-state endurance exercise

Free testosterone (FT) hormonal responses were compared between high-intensity interval exercise (IE) and steadystate endurance exercise (SSE) in endurance trained males (no.=15). IE session was repeated periods of 90-sec treadmill running at 100-110% maximal oxygen uptake (VO2max) and 90-sec active recovery at 40% VO2max for 42-47 min. The SSE session consisted of a continuous 45-min run at 60-65% VO2max. Total work output was equal for each exercise session. A 45-min supine rest control session (CON) was also performed. All three sessions were on separate days. Pre-session (PRE), immediate post-session (POST), and 12-h post-session (12POST) blood samples were collected and used to determine FT, SHBG, LH, 3- α-androstanediol glucuronide (3-α Diol G) and cortisol. Analysis of variance compared IE and SSE biomarker responses to the reference CON session. IE and SSE each caused an increase (p<0.01) in FT, but IE more so than SSE (p<0.05). The 5α-reductase marker 3-α Diol G response at 12POST IE was elevated while FT was reduced (p<0.05); no such change occurred following SSE. These findings suggest IE might produce a more pronounced turnover of FT by androgen sensitive tissue than the SSE form of exercise.

Validation of a sequential extraction and liquid chromatography-tandem mass spectrometric method for determination of dihydrotestosterone, androstanediol and androstanediol-glucuronide in prostate tissues

Androgens are key mediators of prostate development and function, a role that extends to the development of prostate diseases such as benign prostatic hyperplasia (BPH) and prostate cancer. In prostate, DHT is the major androgen and reduction and glucuronidation are the major metabolic pathways for DHT elimination. A streamlined method for quantitation of dihydrotestosterone (DHT), 5α-androstan-3α,17β-diol (3α-diol), and 3α-diol glucuronide (diol-gluc) was established and validated for use with archived prostate tissue specimens to facilitate examination of the roles of the underlying metabolism. This involved a sequential 70/30 hexane/ethyl acetate (hex/EtOAc) extraction of steroids, followed by an ethyl acetate extraction for diol-gluc. Derivatization of the hex/EtOAc fraction with2-fluoro-1-methylpyridinium p-toluene-4-sulfonate (FMP) was used to enhance sensitivity for hydroxyl steroids and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was utilized for analysis of both fractions. The method was validated with calibration standards followed by recovery assessment from spiked samples of BPH and normal prostate. Lower limits of quantitation (LLOQ) were 50 pg/g, 20 pg/g and 100 pg/g for DHT, 3α-diol and diol-gluc, respectively for extracts from 50mg equivalents of tissue. Prepared samples were stable for up to three weeks at 4 °C and 37 °C. The method provides excellent sensitivity and selectivity for determination of tissue levels of DHT, 3α-diol, and diol-gluc. Furthermore, this protocol can easily be extended to other hydroxyl steroids, is relatively straightforward to perform and is an effective tool for assessing steroid levels in archived clinical prostate samples.

Sex steroids and personality traits in the middle luteal phase of healthy normally menstruating young professional women

OBJECTIVE

Sex steroids affect human behavior. The aim of the present study was to determine the associations, if any, between the circulating levels of gonadal and adrenal sex steroids in the mid luteal phase (21st day of a normal menstrual cycle, MC) of young professional women and psychometric parameters as assessed by the Minnesota Multiphasic Personality Inventory (MMPI).

RESULTS

Our results are as follows: (a) The metabolic product of activated adrenal and gonadal androgens, 3alpha-diolG, was modestly but significantly associated with the social introversion scale (10-SI) (r=0.36, p<0.05), independently accounting for 13% of its variation across participants (R²=0.13, F(1,45)=6.58, p=0.014). (b) Total testosterone was significantly associated with the paranoia scale (6-Pa) (r=0.27, p<0.05). Multiple regression analyses indicated that 10% of the variability in paranoia scores could be independently explained by total testosterone levels (R²=0.10, F(1,57)=6.23, p=0.016). We were unable to find any association between the circulating androgens and scores on the masculinity-femininity scale (Mf). We were also unable to document any association between the weak adrenal androgens DHEA and DHEA-S and depression in contrast to several published reports. (c) Our data suggest a marginally significant association between progesterone and scores on the 7-Pt (obsessive/compulsive/psychasthenia) scale (r=0.27, p<0.05). However, only 7% of the 7-Pt variance was explained by progesterone (R²=0.071, F(1,50)=3.81, p=0.057).

CONCLUSIONS

We have found that total testosterone was associated with the paranoia score, the metabolic product of activated androgens, 3alpha-diolG, to social introversion and, finally, progesterone to obsessive-compulsive behavior.

Impact of electro-acupuncture and physical exercise on hyperandrogenism and oligo/amenorrhea in women with polycystic ovary syndrome: a randomized controlled trial

Polycystic ovary syndrome (PCOS), the most common endocrine disorder in women of reproductive age, is characterized by hyperandrogenism, oligo/amenorrhea, and polycystic ovaries. We aimed to determine whether low-frequency electro-acupuncture (EA) would decrease hyperandrogenism and improve oligo/amenorrhea more effectively than physical exercise or no intervention. We randomized 84 women with PCOS, aged 18-37 yr, to 16 wk of low-frequency EA, physical exercise, or no intervention. The primary outcome measure changes in the concentration of total testosterone (T) at week 16 determined by gas and liquid chromatography-mass spectrometry was analyzed by intention to treat. Secondary outcome measures were changes in menstrual frequency; concentrations of androgens, estrogens, androgen precursors, and glucuronidated androgen metabolites; and acne and hirsutism. Outcomes were assessed at baseline, after 16 wk of intervention, and after a 16-wk follow-up. After 16 wk of intervention, circulating T decreased by -25%, androsterone glucuronide by -30%, and androstane-3α,17β-diol-3-glucuronide by -28% in the EA group (P = 0.038, 0.030, and 0.047, respectively vs. exercise); menstrual frequency increased to 0.69/month from 0.28 at baseline in the EA group (P = 0.018 vs. exercise). After the 16-wk follow-up, the acne score decreased by -32% in the EA group (P = 0.006 vs. exercise). Both EA and exercise improved menstrual frequency and decreased the levels of several sex steroids at week 16 and at the 16-wk follow-up compared with no intervention. Low-frequency EA and physical exercise improved hyperandrogenism and menstrual frequency more effectively than no intervention in women with PCOS. Low-frequency EA was superior to physical exercise and may be useful for treating hyperandrogenism and oligo/amenorrhea.

5Alpha-androstane-3beta,7alpha,17beta-triol and 5alpha-androstane-3beta,7beta,17beta-triol as substrates for the human 11beta-hydroxysteroid dehydrogenase type 1

Several studies have shown that the native 7alpha-hydroxy-dehydroepiandrosterone (7alpha-hydroxy-DHEA) is a substrate for the human 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) which converts the 7alpha- into the 7beta-epimer through an oxido-reduction process. Research on the 11beta-HSD1 has investigated its function and structure through using native glucocorticoid substrates and known inhibitors. Other steroid substrates are also of interest. Among testosterone metabolites, 5alpha-androstane-3beta,17beta-diol (Adiol) is a substrate for the cytochrome P450 7B1 which produces 5alpha-androstane-3beta,7alpha,17beta-triol (7alpha-Adiol). This steroid may be a substrate for the 11beta-HSD1. We used recombinant yeast-expressed 11beta-HSD1 with NADP(H)-regenerating systems for examining the products obtained after incubation with 7alpha-Adiol, 7beta-Adiol or 7-oxo-Adiol. Oxidative conditions for the 11beta-HSD1 provided no trace of 7-oxo-Adiol but the inter-conversion of 7alpha- and 7beta-hydroxy-Adiol with V(max)/K(M) (pmol min(-1) microg(-1)/microM) values of 2 and 0.5, respectively. This state was maintained under reductive conditions. The use of a 7-oxo-Adiol substrate under reductive conditions led to the production of both 7alpha- and 7beta-hydroxy-Adiol with V(max)/K(M) values of 3.43 and 0.22, respectively. These findings support the hypothesis that the oxido-reductase and epimerase activities of 11beta-HSD1 depend on the positioning of the steroid substrates within the active site and may provide insight into its fine structure and mechanism of action.

Androgens and prostate cancer risk: a prospective study

BACKGROUND

Androgens have been implicated in prostate tumorigenesis, but prospective studies have overall reported no association between circulating levels of androgens and risk of prostate cancer. However, some recent studies have shown that a high level of testosterone increase the risk of non-aggressive tumors but is associated with a decreased risk of aggressive tumors.

METHODS

We prospectively measured plasma levels of total testosterone, androstanediol glucuronide (A-diol-g) and sex hormone binding globuline (SHBG) and calculated estimated levels of free testosterone, in a nested case-control study of 392 cases and 392 matched controls.

RESULTS

None of the studied hormones were significantly associated with prostate cancer risk in the full study group or in subgroups according to tumor aggressiveness. Odds ratios in the full study group, for top versus bottom quartile, was for total testosterone 1.25 (95% CI = 0.79-2.00; P(trend) = 0.51); free testosterone, 1.31 (95% CI = 0.82-2.07; P(trend) = 0.35); A-diol-g, 0.88 (95% CI = 0.59-1.33; P(trend) = 0.77); and for SHBG, 1.01 (95% CI = 0.64-1.58; P(trend) = 0.94).

CONCLUSIONS

We found no significant associations between androgen levels and risk of prostate cancer in this population-based, non-screened cohort.

Mass spectrometric assay and physiological-pharmacological activity of androgenic neurosteroids

Steroid hormones play a key role in the pathophysiology of several brain disorders. Testosterone modulates neuronal excitability, but the underlying mechanisms are obscure. There is emerging evidence that testosterone-derived "androgenic neurosteroids", 3alpha-androstanediol and 17beta-estradiol, mediate the testosterone effects on neural excitability and seizure susceptibility. Testosterone undergoes metabolism to neurosteroids via two distinct pathways. Aromatization of the A-ring converts testosterone into 17beta-estradiol. Reduction of testosterone by 5alpha-reductase generates 5alpha-dihydrotestosterone, which is then converted to 3alpha-androstanediol, a powerful GABA(A) receptor-modulating neurosteroid with anticonvulsant properties. Although the 3alpha-androstanediol is an emerging neurosteroid in the brain, there is no specific and sensitive assay for determination of 3alpha-androstanediol in biological samples. This article describes the development and validation of mass spectrometric assay of 3alpha-androstanediol, and the molecular mechanisms underlying the testosterone modulation of seizure susceptibility. A liquid chromatography-tandem mass spectrometry assay to measure 3alpha-androstanediol is validated with excellent linearity, specificity, sensitivity, and reproducibility. Testosterone modulation of seizure susceptibility is demonstrated to occur through its conversion to neurosteroids with "anticonvulsant" and "proconvulsant" actions and hence the net effect of testosterone on neural excitability and seizure activity depends on the levels of distinct testosterone metabolites. The proconvulsant effect of testosterone is associated with increases in plasma 17beta-estradiol concentrations. The 5alpha-reduced metabolites of testosterone, 5alpha-dihydrotestosterone and 3alpha-androstanediol, had powerful anticonvulsant activity. Overall, the testosterone-derived neurosteroids 3alpha-androstanediol and 17beta-estradiol could contribute to the net cellular actions of testosterone in the brain. Because 3alpha-androstanediol is a potent positive allosteric modulator of GABA(A) receptors, it could serve as an endogenous neuromodulator of neuronal excitability in men. The 3alpha-androstanediol assay is an important tool in this area because of the growing interest in the potential to use adjuvant aromatase inhibitor therapy to improve treatment of epilepsy.

Serum sex steroid hormones and lower urinary tract symptoms in Third National Health and Nutrition Examination Survey (NHANES III)

OBJECTIVES

To evaluate the association of circulating sex steroid hormones and sex hormone binding globulin (SHBG) with lower urinary tract symptoms (LUTS).

METHODS

We included 260 men, 60 years old or older, who participated in Phase 1 (1988 to 1991) of the Third National Health and Nutrition Examination Survey and for whom surplus serum was available. We measured the serum concentrations of testosterone, androstanediol glucuronide (AAG), estradiol, and SHBG. Free testosterone was calculated from the circulating testosterone, SHBG, and albumin. The cases (n = 128) were men with two to four symptoms (nocturia, hesitancy, incomplete emptying, and weak stream), but who had never undergone noncancer prostate surgery. The controls (n = 132) were men who neither had symptoms nor had undergone noncancer prostate surgery. We adjusted for age, race/ethnicity, waist circumference, cigarette smoking, alcohol consumption, and physical activity in logistic regression models and used sampling weights.

RESULTS

The cases had statistically significantly greater AAG and estradiol concentrations than did the controls. After multivariate adjustment, the men in the top tertile of AAG (odds ratio 2.62, 95% confidence interval 1.12 to 6.14) had a greater risk of LUTS compared with men in the bottom two tertiles. Also, men with a greater estradiol concentration (odds ratio 1.78, 95% confidence interval 0.91 to 3.49) and a greater estradiol/SHBG molar ratio (odds ratio 2.41, 95% confidence interval 1.39 to 4.17) had a greater risk of LUTS than did men with lower concentrations. No consistent associations were seen for circulating testosterone, free testosterone, or SHBG.

CONCLUSIONS

In this cross-sectional study representative of older U.S. men, circulating AAG, a metabolite of dihydrotestosterone, and estradiol were associated with an increased risk of having LUTS.

Serum levels of 3α-androstanediol glucuronide in young women with polycystic ovary syndrome, idiopathic hirsutism and in normal subjects

OBJECTIVE

The study objective was to assess the role of 3alpha-androstanediol glucuronide (3alpha-diolG) as the marker of peripheral androgen action in the young women with hirsutism diagnosed as polycystic ovary syndrome (PCOS), in patients with idiopathic hirsutism (IH) and in normal non-hirsute women.

STUDY DESIGN

Fifty-nine young women with mean age 21.90+/-3.52 years suffered from hirsutism were included in the study. Among these 59 hirsute women 31 women with mean age 21.60+/-3.56 years were diagnosed as PCOS and 28 women with mean age 22.20+/-3.59 years were classified as idiopathic hirsutism patients. Twenty-seven normal women, age-matched (mean age 22.60+/-2.90 years), without signs of hirsutism and with normal menstrual cycle served as control for this study. Serum was collected from women with hirsutism (due to PCOS or idiopathic hirsutism) and from non-hirsute women. Serum levels of 3alpha-androstanediol glucuronide (3alpha-diolG), main androgens such as: testosterone, free testosterone, dehydroepiandrosterone (DHEAS) and also others hormones such as follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2) and sex hormone-binding globuline (SHBG) were measured using radioimmunoassay (RIA) method in the study and control group. Hirutism was assessed using modified Ferriman-Gallwey method. Serum 3alpha-diolG levels in PCOS women were significantly higher than in controls.

RESULTS

There were no significant differences between serum 3alpha-diolG levels in PCOS group and IH group. Similarly, there were significant differences between serum 3alpha-diolG levels in IH group and control subjects.

CONCLUSION

We conclude that 3alpha-diolG is not useful as the marker for peripheral androgen metabolism and for differentiation between idiopathic hirsutism and PCO-related hirsutism.

2β-(N-Substituted Piperazino)-5α-Androstane-3α,17β-Diols: Parallel Solid-Phase Synthesis and Antiproliferative Activity on Human Leukemia HL-60 Cells

Leukemia is the most common cancer affecting children. A steroid possessing a methylpiperazine nucleus was recently reported to inhibit the proliferation of HL-60 leukemia cells. To speed up the development of this promising potential new drug, we generated libraries of analogues using parallel solid-phase organic synthesis (SPOS). A 6-step sequence of reactions, starting from dihydrotestosterone, afforded a steroidal 2,3alpha-epoxide, which was selectively opened to give, after N-Fmoc protection, a diol with suitable stereochemistry. The difference of reactivity between 3alpha-OH and 17beta-OH was then used to allow the regioselective coupling of 17beta-OH to chloro-activated butyldiethylsilane polystyrene. We next generated three libraries of 2beta-piperazinyl-5alpha-androstane-3alpha,17beta-diol N-derivatives with 1, 2, or 3 levels of molecular diversity in acceptable yields and purities for our biological screening assay. Several members of these libraries were more potent than the lead compound, especially five members with a proline as the first level of diversity and a cyclohexylcarbonyl, methylbutyryl, cyclohexylacetyl, cyclopentylpropionyl, or hexanoyl as the second level of diversity. They efficiently inhibited HL-60 cell proliferation with IC50 values of 0.58, 0.66, 1.78, 1.98, and 2.57 microM, respectively. The present work demonstrates the potential of our SPOS approach for the optimization of a new class of cytotoxic agents.

Consumption of Lactobacillus acidophilus and Bifidobacterium longum does not alter phytoestrogen metabolism and plasma hormones in men: a pilot study

OBJECTIVE

The aim of this study was to determine whether equol excretion status and plasma hormone and leptin concentrations can be influenced by consumption of a probiotic supplement. A secondary focus was to investigate whether male equol excretors have a hormone profile consistent with reduced prostate cancer risk.

DESIGN

The design was a randomized, single-blinded, placebo-controlled, parallel-arm trial.

SUBJECTS

Thirty-one (31) of the initially enrolled 39 subjects, 18 to 37 years old, completed all study requirements.

INTERVENTION

Subjects consumed either probiotic capsules (containing Lactobacillus acidophilus and Bifidobacterium longum) or placebo capsules for 2 months. Fasting plasma concentrations of testosterone (T), dihydrotestosterone (DHT), androstanediol glucuronide (AAG), androstenedione (A), dehydroepiandrosterone sulfate (DHEAS), sex hormone-binding globulin (SHBG), and leptin were measured on days 1 and 57. Urinary excretion of genistein, glycitein, daidzein, O-desmethylangolensin (O-Dma), and equol was measured on days 4 and 61 following a 4-day soy challenge.

RESULTS

Probiotic consumption did not significantly alter equol excretor status, plasma hormone, or leptin concentrations in these subjects. At baseline, there were no differences in plasma hormone concentrations between equol excretors and nonexcretors; however, the low number of equol excretors included in this study limits the strength of this finding.

CONCLUSIONS

The 2-month intervention with probiotic capsules did not significantly alter equol excretion, plasma hormone, or leptin concentrations in these subjects. A secondary finding was that male equol excretors in this study did not exhibit a hormone profile consistent with reduced prostate cancer risk, although this result should be interpreted with caution.

Polymorphisms in the CYP19 gene may affect the positive correlations between serum and urine phytoestrogen metabolites and plasma androgen concentrations in men

Phytoestrogens have been hypothesized to protect against prostate cancer via modulation of circulating androgen concentrations. We conducted a cross-sectional study of 267 men in the Norfolk arm of the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort with 2 aims: first, to investigate the association between phytoestrogen exposure (measured from diet, urine, and serum) and plasma concentrations of sex hormone-binding globulin (SHBG), androstanediol glucuronide, testosterone and Free Androgen Index (FAI); and second, whether the association may be modified by polymorphisms in CYP19 and SHBG genes. Dietary daidzein and genistein intakes were obtained from food diaries and computed using an in-house food composition database. Urinary and serum concentrations of 3 isoflavones (daidzein, genistein, glycitein), 2 daidzein metabolites O-desmethylangolensin (O-DMA) and 2 lignan metabolites (enterodiol and enterolactone) were measured using mass spectrometry. There was no association between dietary, urinary, and serum phytoestrogens and plasma SHBG concentrations. Enterolactone was positively associated with plasma androstanediol glucuronide concentrations (urinary enterolactone: r = 0.127, P = 0.043; serum enterolactone: r = 0.172, P = 0.006) and FAI (urinary enterolactone: r = 0.115, P = 0.067; serum enterolactone: r = 0.158, P = 0.011). Both urinary and serum equol were associated with plasma testosterone (urinary equol: r = 0.332, P = 0.013; serum equol: r = 0.318, P = 0.018) and FAI (urinary equol: r = 0.297, P = 0.027; serum equol: r = 0.380, P = 0.004) among men with the TT genotype but not the CC or CT genotypes (r = -0.029 to -0.134, P = 0.091-0.717) for the CYP19 3'untranslated region (UTR) T-C polymorphism. Urinary and serum enterolactone showed similar genotype-dependent associations with testosterone but not with FAI. In this first study on phytoestrogen-gene associations in men, we conclude that enterolactone and equol are positively associated with plasma androgen concentrations, and interactions with CYP19 gene may be involved.

Effects of oral administration of androstenedione on plasma androgens in young women using hormonal contraception

Androstenedione as a dietary supplement has been targeted at the sporting community, but there are limited data regarding its effects on plasma androgens in young women. A double-blind, cross-over study was undertaken involving 10 women (20-32 yr) using hormonal contraception. Because contamination of supplements has been reported, an in-house oral formulation was prepared containing purified androstenedione, the control being lactose only. After oral administration of a single dose of androstenedione (100 mg), blood was collected frequently up to 8 h and at 24 h. Maximum plasma androgen concentrations observed between volunteers were well above the upper limit of reference ranges for women, being 121-346 nmol/liter for androstenedione, 14-54 nmol/liter for testosterone (T), 11-32 nmol/liter for 5alpha-dihydrotestosterone, and 23-90 nmol/liter for 3alpha-androstanediol glucuronide. The free androgen index and T concentration changed in a similar manner. The mean change in area under the plasma concentration-time curve (0-24 h), compared with control data were: androstenedione approximately 7-fold, T approximately 16-fold, 5alpha-dihydrotestosterone approximately 9-fold, and 3alpha-androstanediol glucuronide approximately 5-fold; the mean conversion ratio of androstenedione to T was 12.5% (range 7.8-21.6%). Increases in T area under the plasma concentration-time curve were correlated with SHBG concentration (r = 0.80; P = 0.005). Formulation characteristics and SHBG levels appear to be important factors when considering plasma androgen increases after acute androstenedione administration.

Prostate-specific antigen, sex steroid hormones, and the insulin-like growth factor axis in U.S.-born, Jamaican, and Haitian black men: A pilot study

OBJECTIVES

African-Caribbean men have a risk of prostate cancer comparable to that of African-American men. To begin exploring potential risk factors for prostate cancer in these high-risk black subgroups, we conducted a pilot study in Brooklyn, New York, a community with large numbers of African-Americans and immigrants from Jamaica and Haiti.

METHODS

Black men, 35 to 65 years of age, who were born in the United States, Jamaica, or Haiti were recruited in Brooklyn. The subjects' serum samples were analyzed for prostate-specific antigen (PSA) and the following hormones, which may be related to prostate cancer: testosterone, sex hormone-binding globulin, 3alpha-androstanediol glucuronide, insulin-like growth factor-1 (IGF-1), and IGF-binding protein-3 (IGFBP-3). Subgroup differences in PSA and hormonal levels, adjusted for relevant covariates, were explored using analysis of variance techniques.

RESULTS

For 3 months, we recruited 21 U.S.-born, 20 Jamaican-born, and 24 Haitian-born black men using various methods. The mean age-adjusted PSA level was 1.04 ng/mL in the U.S.-born men, 1.09 ng/mL in the Jamaican-born men, and 0.85 ng/mL in the Haitian-born men (P = 0.55). The mean age-adjusted hormone levels, as well as testosterone/sex hormone-binding globulin and IGF-1/IGFBP-3 ratios, also were not significantly different statistically across the subgroups.

CONCLUSIONS

It is feasible to conduct epidemiologic studies of prostate cancer in these high-risk black subgroups in Brooklyn. Our preliminary data suggest that the serum levels of PSA and potential hormonal risk factors are similar among U.S.-born, Jamaican-born, and Haitian-born black men. Larger follow-up studies are being planned to confirm these findings.

Synthesis of 3-methyl-3-hydroxy-6-oxo-androstane derivatives

3alpha,17beta-Dihydroxy-3beta-methyl-5alpha-androstan-6-one (1) and 3beta,17beta-dihydroxy-3alpha-methyl-5alpha-androstan-6-one (13) were prepared by the reaction of methylmagnesium bromide with the 3-ketosteroids. Structures and configurations in position 3 were determined by NMR spectra. Substitution in the position 6 influences the ratio of the products.

Sugar/steroid/sugar conjugates: sensitivity of lipid binding to sugar structure

[structure: see text]. Three steroids, each bearing a sugar on rings A and D, have been synthesized. Their effect on the "melting" behavior of a lipid bilayer depends on whether the sugar is glucose, galactose, or mannose. Packing constraints dictate how the lipid bilayer responds to the sugars.

Pharmacokinetics of dehydroepiandrosterone and its metabolites after long-term daily oral administration to healthy young men

OBJECTIVE

To determine the effects of dehydroepiandrosterone (DHEA) supplementation on the pharmacokinetics of DHEA and its metabolites and the reproductive axis of healthy young men.

DESIGN

A prospective, randomized, double-blind, placebo-controlled pharmacokinetic study.

SETTING

General Clinical Research Center and laboratories at the Keck School of Medicine of the University of Southern California, Los Angeles, California.

PATIENT(S)

Fourteen healthy men, ages 18-42 years.

INTERVENTION(S)

Daily oral administration of placebo (n = 5), 50 mg DHEA (n = 4), or 200 mg DHEA (n = 5) for 6 months. Blood samples were collected at frequent intervals on day 1 and at months 3 and 6 of treatment.

MAIN OUTCOME MEASURE(S)

Quantification of DHEA, DHEA sulfate (DHEAS), androstenedione, T, E(2), dihydrotestosterone (DHT), and 5alpha-androstane-3alpha-17beta-diol glucuronide (ADG). Physical examination, semen analysis, serum LH, FSH, prostate-specific antigen, and general chemistries were carried out.

RESULT(S)

Baseline DHEA, DHEAS, and ADG levels increased significantly from day 1 to months 3 and 6 in the DHEA treatment groups but not in the placebo group. No significant changes were observed in pharmacokinetic values. Clinical parameters were not affected.

CONCLUSION(S)

DHEA, DHEAS, and ADG increased significantly during 6 months of daily DHEA supplementation. Although the pharmacokinetics of DHEA and its metabolites are not altered, sustained baseline elevation of ADG, a distal DHT metabolite, raises concerns about the potential negative impact of DHEA supplementation on the prostate gland.

Anticonvulsant activity of the testosterone-derived neurosteroid 3α-androstanediol

3alpha-Androstanediol is synthesized from testosterone in peripheral tissues and in the brain, but the clinical importance of this neurosteroid remains unclear. This study evaluated the effects of 3alpha-androstanediol on seizure susceptibility in mouse models of epilepsy. 3alpha-Androstanediol protected mice against seizures induced by GABAA receptor antagonists pentylenetetrazol, picrotoxin, and beta-carboline ester in a dose-dependent fashion. However, 3alpha-androstanediol was inactive against seizures induced by glutamate receptor agonists kainic acid, NMDA and 4-aminopyridine. Pretreatment with the androgen receptor antagonist flutamide had no effect on seizure protection by 3alpha-androstanediol. These results suggest that 3alpha-androstanediol has powerful anticonvulsant activity that occurs largely through non-genomic mechanisms. Testosterone-derived 3alpha-androstanediol might be an endogenous protective neurosteroid in the brain.

5alpha-Reduced androgens block estradiol-BSA-stimulated release of oxytocin

In this study we test the postulate that estradiol conjugated to bovine serum albumin (E-BSA) acts via receptors for the steroid-binding protein sex hormone binding globulin (SHBG) by attempting to block E-BSA-stimulated release of oxytocin with two antagonists of SHBG receptor actions: the 5alpha-reduced androgens dihydrotestosterone (DHT) and 3alpha-diol. Simultaneous superfusion with either DHT or 3alpha-diol significantly blocked E-BSA-stimulated release of oxytocin. We also found that a wide range of free 17beta-estradiol was unable to stimulate oxytocin release, suggesting that E-BSA stimulates receptors other than those for free estradiol to release oxytocin, perhaps SHBG receptors.

Frequencies of the D85 and Y85 variants of UGT2B15 in children and adolescent girls with hyperandrogenism

Premature pubarche (PP) appears to be a risk factor for the subsequent development of polycystic ovary syndrome (PCOS) during or after puberty. The clinical manifestations due to hyperandrogenism are influenced by androgen production, androgen metabolism, and androgen receptor activity. Glucuronidation by the UDP-glucuronyltransferase 2B (UGT2B) family of enzymes is one mechanism through which androgens are inactivated. Two variants differing by the amino acid at codon 85 have been described for UGT2B15, a member of this family. Both variants show similar substrate specificities. However, for the substrates alpha-androstanediol (alpha-diol) and dihydrotestosterone (DHT), the D85 variant has a lower Vmax than the Y85 variant. We compared the frequencies of these variants in 69 patients with PP, 46 adolescent girls with hyperandrogenism (HA), and 88 healthy controls to determine whether the frequency of the D85 variant was increased among patients with hyperandrogenism. Allele frequencies were comparable in children with PP, adolescent girls with HA, and healthy control subjects. Although D85 and Y85 appear to be common variants, we cannot exclude the possibility that the UGT2B15 gene represents a minor modifying locus.

Oral and transdermal estrogens both lower plasma total homocysteine in male-to-female transsexuals

Plasma total homocysteine (tHcy) levels are on average lower in women versus men, indicating an estrogenic effect. Oral estrogens (absorbed via the liver) may be hypothesized to have stronger effects on hepatic homocysteine metabolism than transdermal estrogens. We randomly assigned 30 male-to-female transsexuals (20-44 years old) to 4 months' administration of oral ethinyl estradiol (n=15) or transdermal 17beta-estradiol (n=15), both with the antiandrogen cyproterone acetate (CA). Ten other male controls were treated with CA only. At baseline and after 2 and 4 months, plasma tHcy was analyzed in conjunction with plasma folate. Oral ethinyl estradiol and transdermal 17beta-estradiol similarly reduced plasma tHcy (geometric mean 10.6 micromol/l [95% CI 8.2-13.9] to 7.5 [6.5; 8.8], and 11.3 [8.1; 16.4] to 8.4 [6.5; 11.1]; P<0.001 for both), whereas CA had no effects. No effects were found on folate levels. Thus, oral and transdermal estrogens decrease plasma tHcy to a similar degree (by geometric mean -26%), which suggests that a hepatic mechanism is unlikely to play an important role in the decline of tHcy levels.

A highly specific heterologous enzyme immunoassay for 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide (androstanediol-17G) and developmental patterns of urinary androstanediol-17G excretions

We established a highly specific enzyme immunoassay (EIA) for 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide (androstanediol-17G). Rabbit antisera raised against 5 alpha-androstane-3 alpha, 11 alpha, 17 beta-triol 17-glucuronide 11-glutaryl bovine serum albumin and a heterologous tracer of androstanediol-17G conjugated with horseradish peroxidase at the glucuronic acid group were used. The EIA showed excellent specificity: there were no remarkable cross-reactivities with related androgens. The assay range for urine samples was 0.3-30 ng/ml. Recoveries of standards added to samples were 100-108%. Intra-assay and inter-assay coefficients of variation were 2.9-4.4% and 5.7-7.9%, respectively. The EIA was applied to urine samples of 407 males and 322 females to determine developmental patterns and normal ranges of androstanediol-17G excretions in 11 age groups (0 y, 1 y, 2-3 y, 4-5 y, 6-7 y, 8-9 y, 10-11 y, 12-13 y, 14-15 y, 16-17 y, and over 18 y). Urinary androstanediol-17G/creatinine (androstanediol-17G/Cre) ratios in both sexes were high in infancy, tended to decrease during childhood, and began to increase near adolescence. While androstanediol-17G/Cre ratio in girls increased at 8-9 y and reached a plateau during adolescence, that in boys increased at 10-11 y and continued to increase throughout adolescence. Androstanediol-17G/Cre ratios in girls were higher than those in boys at 6-7 y (P < 0.05) and at 8-9 y (P < 0.01). Androstanediol-17G/Cre ratios in boys were higher than those in girls at 12-13 y and at older ages (P < 0.01). These developmental patterns are parallel to age-related changes in androgenicity and serum androstanediol-17G, suggesting that urinary androstanediol-17G/Cre ratio could be a good marker for androgenicity in childhood.

Photoaffinity labeling of human sex hormone-binding globulin using 17alpha-alkylamine derivatives of 3beta-androstanediol substituted with azidonitrophenylamido, azidonitrophenylamino, or trifluoroazidonitrophenylamino chromophores. Localization of Trp-84 in the vicinity of the steroid-binding site

Purified human SHBG was photoaffinity labeled with 17alpha-aminomethyl (M), 17alpha-aminoethyl (E), and 17alpha-aminopropyl (P) derivatives of [3alpha-(3)H]-5alpha-androstane-3beta,17beta-diol coupled to 5-azido-2-nitrobenzoylamido (ANB), 4-azido-2-nitrophenylamino (ANP), and 5-azido-2-nitro-3,4,6-trifluorophenylamino (ANTFP) chromophores. Successful labeling was achieved in all cases except for the two photoreagents with the shortest side chains, namely, ANP-M and ANTFP-M derivatives. Edman sequencing and mass spectrometry of immunopurified photolabeled tryptic fragments revealed that radioactivity was present either on the sequence of residues 73-94, uniquely at the level of Trp-84 (stable covalent labeling), or on one of the two overlapping sequences of residues 126-134 and 126-135, at the level of Pro-130 (labile labeling) and Lys-134 (either stable or partially labile labeling), respectively. The same Trp-84 was photolabeled with the three ANB derivatives of increasing lengths, and by the ANP-P photoreagent. This residue was the exclusive target for the shortest [(3)H]ANB-M photoreagent but was a minor site for the longest [(3)H]ANB-P photoreagent, essentially recovered at the level of Pro-130. The [(3)H]ANB-E photoreagent of intermediate size also labeled exclusively Trp-84, except in some experiments in which photolabeling was recovered predominantly at the level of Pro-130. The [(3)H]ANP-P photoreagent with an overall length similar to that of the ANB-P photoreagent labeled simultaneously Trp-84 (minor site) and Lys-134. The other [(3)H]ANP-E, [(3)H]ANTFP-E, and [(3)H]ANTFP-P derivatives labeled in all cases Lys-134. These findings indicate that the conserved Trp-84 and the two Pro-130 and Lys-134 residues are all located in the vicinity of the D ring of steroid ligands and remain freely accessible from the C17alpha position, thus providing biochemical data delineating the corresponding region of the steroid-binding site.

Configurational analysis and relative binding affinities of 16-methyl-5alpha-androstane derivatives

The four possible isomers 16beta-hydroxymethyl-5alpha-androstane-3beta,17beta-diol 1, 16alpha-hydroxymethyl-5alpha-androstane-3beta,17beta-diol 2, 16beta-hydroxymethyl-5alpha-androstane-3beta,17alpha-diol 3 and 16alpha-hydroxymethyl-5alpha-androstane-3beta,17alpha-diol 4 with proven configuration were converted into the corresponding 16beta-methyl-5alpha-androstane-3beta,17beta-diol 5, 16alpha-methyl-5alpha-androstane-3beta,17beta-diol 6, 16beta-methyl-5alpha-androstane-3beta,17alpha-diol 7, 16alpha-methyl-5alpha-androstane-3beta,17alpha-diol 8, furthermore into the 16beta-methyl-17beta-hydroxy-5alpha-androstane-3-one 13, 16alpha-methyl-17beta-hydroxy-5alpha-androstan-3-one 14, 16beta-methyl-17alpha-hydroxy-5alpha-androstan-3-one 15 and 16alpha-methyl-17alpha-hydroxy-5alpha-androstan-3-one 16. The steric structures of the resulting epimers were determined by means of 1H-, and 13C-NMR spectroscopy. In this way, comparison was possible with the C-16 epimers 5, 6 and 13, 14 prepared earlier by a different route, and the series of isomers could be completed with the steric structures of 16beta-methyl-17alpha-hydroxy-5alpha-androstan-3beta-ol 7 and 16alpha-methyl-17alpha-hydroxy-5alpha 8 and with their 3-keto derivatives 15 and 16. The relative binding affinities of the 16-methyl-5alpha-androstane-3beta,17-diols 5, 6, 7, 8 and 17-hydroxy-16-methyl-5alpha-androstan-3-ones 13, 14, 15, 16 were studied. The introduction of a 16-methyl substituent into 5alpha-androstane molecules substantially decreases the binding affinity to the androgen receptor and 16alpha-methyl derivatives were always bound more weakly than the 16beta-methyl isomers.

Familial resemblance for free androgens and androgen glucuronides in sedentary black and white individuals: the HERITAGE Family Study. Health, Risk Factors, Exercise Training and Genetics

Familial correlation analyses were used to evaluate the familial aggregation of plasma androgens and androgen glucuronides (testosterone (TESTO), dihydrotestosterone (DHT), androstane-3 alpha,17 beta-diol glucuronide (3 alpha-DIOL-G), and androsterone glucuronide (ADT-G)) in 505 members of 99 white families and 296 members of 111 black families participating in the Health, Risk Factors, Exercise Training and Genetics (HERITAGE) Family Study. Each of these four measures was determined by RIA after separation of conjugated and unconjugated steroid using C18 column chromatography. All participants were sedentary prior to being including in this study. Significant spouse correlations, as well as parent-offspring and sibling correlations, were found for TESTO, DHT, 3 alpha-DIOL-G, and ADT-G in the white sample, suggesting that common familial environments and genes contribute to the familial resemblance. In the black sample, significant sibling and parent-offspring correlations were found for all four phenotypes, while the spouse correlation was marginally significant for 3 alpha-DIOL-G and not significant for TESTO, DHT, and ADT-G. The non-significance of spouse correlations in the black individuals may be due to the small number of spouse pairs. The maximal heritability estimates of TESTO, DHT, 3 alpha-DIOL-G, and ADT-G were 69%, 87%, 74%, and 56% for white individuals and 70%, 73%, 62%, and 48% for black individuals respectively. Sex differences in heritability estimates were found in the white individuals, but they were less dramatic in the black individuals. In conclusion, plasma levels of androgens and androgen glucuronides are highly heritable in both white individuals and black individuals. There are notable sex differences in the white individuals.

Role of canine basal cells in postnatal prostatic development, induction of hyperplasia, and sex hormone-stimulated growth; and the ductal origin of carcinoma

BACKGROUND

The canine prostate has often been proposed as a model for abnormal growth of the human gland. Hyperplasia of the prostate is common in aging men and has been estimated to be present in 100% of old intact dogs. While prostatic carcinoma is common in older men, it appears to be rare in dogs and unlike the disease in humans, it occurs with relatively high frequency in castrated animals. Since basal cells are thought to be key participants in normal and abnormal growth of the human gland, we used immunohistochemistry to investigate the role that they may play in canine prostatic development, the evolution of hyperplasia and carcinoma, and the effects of sex hormones on these cells.

METHODS

Prostate specimens were obtained at autopsy from seven sexually immature dogs, autopsy and biopsy samples from 14 sexually mature intact animals, from four castrates, and from19 dogs with prostatic carcinoma. In addition, we also studied the prostates from two intact dogs treated with 5alpha-dihydrotestosterone (DHT) for 6 months and two castrated dogs that were subsequently treated with 5alpha-androstane-3alpha diol and estradiol-17alpha, as well as specimens from two sexually ablated animals given DHT for 2 weeks. All specimens were immunostained for high molecular weight cytokeratin (HMC), pancytokeratin, androgen receptor (AR), and the proliferative marker KI-67.

RESULTS

We find that basal cells are the major proliferative cell type in the neonatal and adult canine prostate and that the expression of HMC staining, which defines these cells, may be regulated by androgens. In the adult gland, ductal basal cells formed a contiguous layer, whereas those lining acini were discontinuous. Populations of both basal cell types were variably AR positive, but while HMC immunostaining was abolished in acinar cells following long-term castration, staining remained in ductal cell counterparts. Paralleling the histological development of hyperplasia, the acinar basal cell population increased with age and were the major cell type that expressed KI-67. In contrast, ductal basal cell populations did not expand in the prostates of older dogs and were seldom positively stained for KI-67. The numbers of HMC and KI-67-stained acinar basal cells were dramatically increased in the prostates of intact dogs treated with DHT when compared with glands of untreated controls. This was not the case with ductal basal cells. Androgens given alone or together with estrogen to castrated dogs induced widespread HMC and KI-67 immunostaining in both populations of basal cells. In addition, our results indicate that the majority of canine prostatic carcinomas likely arise exclusively from ductal epithelium. Only one of the 19 cases of carcinoma contained cells that expressed AR, which suggests that androgens may not be required for the initiation or progression of these cancers.

CONCLUSIONS

Our findings indicate that two biologically distinct populations of basal cells may exist in the canine prostate. In this regard, the age-related expansion of proliferating acinar basal cell populations, probably mediated by sex steroids, is a key factor in the pathogenesis of canine prostatic hyperplasia. Additionally, we find that prostatic carcinoma in the dog likely arises from ductal cells. Taken together, these findings may indicate that canine acinar basal cells and ductal epithelium have separate susceptibilities to factors that promote hyperplastic or neoplastic development.

Pharmacokinetics of testosterone after percutaneous gel or buccal administration

OBJECTIVE

To determine the pharmacokinetics of testosterone following its administration using transdermal gel or buccal lozenges.

DESIGN

Pilot study.

SETTING

University-based hospital.

PATIENT(S)

Ten bilaterally oophorectomized women.

INTERVENTION(S)

Daily micronized testosterone gel (1 mg) and testosterone propionate lozenge (1 mg).

MAIN OUTCOME MEASURE(S)

Total testosterone, androstenedione, dihydrotestosterone, 3alpha-androstanediol glucuronide, and sex hormone-binding globulin were measured in serum by specific radioimmunoassays; free testosterone levels were also calculated.

RESULT(S)

Before treatment, serum testosterone levels in the groups using the lozenge and gel were 16 +/- 4.0 and 20 +/- 6.0 ng/dL, respectively. Mean maximum testosterone levels obtained with the lozenge occurred 1 hour after administration on days 1 (692 +/- 236 ng/dL) and 14 (836 +/- 309 ng/dL) of treatment and fell precipitously thereafter. In contrast, testosterone levels obtained with the gel showed a prolonged rise reaching maximal levels of 97 +/- 78 and 100 +/- 60 ng/dL after 18 hours. The serum level patterns of free testosterone, dihydrotestosterone, and 3alpha-androstanediol glucuronide were similar to the corresponding total testosterone levels.

CONCLUSION(S)

Administration of testosterone lozenge by buccal absorption produced a rapid and brief elevation of testosterone levels, with levels reaching upper limits of the male range. In contrast, transdermal testosterone gel absorption resulted in a prolonged elevation of testosterone levels, which were in the hyperandrogenic female range but resembled steady state pharmacokinetics.

Role of canine basal cells in prostatic post natal development, induction of hyperplasia, sex hormone-stimulated growth; and the ductal origin of carcinoma

BACKGROUND

The canine prostate has often been proposed as a model for abnormal growth of the human gland. Hyperplasia of the prostate is common in aging men and has been estimated to be present in 100% of old intact dogs. While prostatic carcinoma is common in older men it appears to be rare in dogs and unlike the disease in humans it occurs with relatively high frequency in castrated animals. Since basal cells are thought to be key participants in normal and abnormal growth of the human gland, we used immunohistochemistry to investigate the role that they may play in canine prostatic development, the evolution of hyperplasia and carcinoma, and the effects of sex hormones on these cells.

METHODS

Prostate specimens were obtained at autopsy from seven sexually immature dogs, autopsy and biopsy samples from 14 sexually mature intact animals, from four castrates, and from 19 dogs with prostatic carcinoma. In addition, we also studied the prostates from two intact dogs treated with 5 alpha-dihydrotestosterone (DHT) for 6 months and two castrated dogs that were subsequently treated with 5 alpha-androstane-3 alpha diol and estradiol-17 alpha as well as specimens from two sexually ablated animals given DHT for 2 weeks. All specimens were immunostained for high molecular weight cytokeratin (HMC), Pancytokeratin, androgen receptor (AR), and the proliferative marker KI-67.

RESULTS

We find that basal cells are the major proliferative cell type in the neonatal and adult canine prostate and that the expression of HMC staining, which defines these cells, may be regulated by androgens. In the adult gland, ductal basal cells formed a contiguous layer whereas those lining acini were discontinuous. Populations of both basal cell types were variably AR positive but while HMC immunostaining was abolished in acinar cells following long-term castration, staining remained in ductal cell counterparts. Paralleling the histological development of hyperplasia, the acinar basal cell population increased with age and were the major cell type that expressed KI-67. In contrast, ductal basal cell populations did not expand in the prostates of older dogs and were seldom positively stained for KI-67. The numbers of HMC and KI-67-stained acinar basal cells were dramatically increased in the prostates of intact dogs treated with DHT when compared with glands of untreated controls. This was not the case with ductal basal cells. Androgens given alone or together with estrogen to castrated dogs induced widespread HMC and KI-67 immunostaining in both populations of basal cells. In addition, our results indicate that the majority of canine prostatic carcinomas likely arise exclusively from ductal epithelium. Only one of the 19 cases of carcinoma contained cells that expressed AR which suggests that androgens may not be required for the initiation or progression of these cancers.

CONCLUSIONS

Our findings indicate that two biologically distinct populations of basal cells may exist in the canine prostate. In this regard the age-related expansion of proliferating acinar basal cell populations, probably mediated by sex steroids, is a key factor in the pathogenesis of canine prostatic hyperplasia. Additionally we find that prostatic carcinoma in the dog likely arises from ductal cells. Taken together these findings may indicate that canine acinar basal cells and ductal epithelium have separate susceptibilities to factors that promote hyperplastic or neoplastic development. Prostate 47:149-163, 2001.

Clinical assessment and serum hormonal profile in prepubertal hypertrichosis

Twenty-two prepubertal girls with hypertrichosis were studied and compared to 10 prepubertal normal girls. Hypertrichosis was assessed according to a score that considers the amount and the distribution of vellus hair in androgen- and non-androgen-sensitive areas. Serum androgen profile and free androgen index (FAI) were determined in both groups. The hypertrichosis score was higher in patients than in the normal girls. Testosterone levels and FAI were increased in patients when compared to control; 3alpha-androstanediol glucuronide levels above 2 SD from the control mean were found in 10 girls and all hormonal parameters falling in the normal range were found in 4 girls. The new score designed to assess the degree of hypertrichosis was useful to differentiate between normal and pathological hair growth. Although most of the girls with prepubertal hypertrichosis showed an increased androgen bio-availability, a slight increase in peripheral 5alpha-reductase activity and a completely normal androgen profile was also associated with a pathological hair growth.

Lifestyle determinants of 5alpha-reductase metabolites in older African-American, white, and Asian-American men

Men with higher endogenous 5alpha-reductase activity may have higher prostate cancer risk. This hypothesis raises two questions: (a) Could racial differences in 5alpha-reductase activity explain the observed racial differences in prostate cancer risk? and (b) Could a man reduce his activity level by modifying his lifestyle? To address these questions, we measured two hormonal indices of 5alpha-reductase activity [serum levels of androstane-3alpha-17beta-diol glucuronide (3alpha-diol G) and androsterone glucuronide (AG)] in healthy, older African-American, white, and Asian-American men, who are at high, intermediate, and low prostate cancer risk, respectively. We also examined associations between these metabolite levels and such lifestyle characteristics as body size and physical activity as well as select aspects of medical history and family history of prostate cancer. Men included in this cross-sectional analysis (n = 1054) had served as control subjects in a population-based case-control study of prostate cancer we conducted in California, Hawaii, and Vancouver, Canada and provided information on certain personal attributes and donated blood between March 1990 and March 1992. In this study, concentrations of 3alpha-diol G declined significantly with age and increased significantly with body mass index. Mean levels of 3alpha-diol G, adjusted for age and body mass index, were 6.1 ng/ml in African-Americans, 6.9 ng/ml in whites and 4.8 ng/ml in Asian-Americans. These differences were statistically significant (African-Americans versus whites: P < 0.01; whites versus Asian-Americans: P < 0.001). Concentrations of AG decreased significantly with age, but only in whites, and were unrelated to any of the reported personal attributes. Mean levels of AG, adjusted for age, were 44.1 ng/ml in African-Americans, 44.9 ng/ml in whites, and 37.5 ng/ml in Asian-Americans (Asian-Americans versus whites, P < 0.001). In conclusion, older African-American and white men have similar levels of these two indices of 5alpha-reductase activity, and these levels are higher than those of older Asian-American men. This difference may be related to the lower prostate cancer risk in Asian-Americans.

Are serum hormones associated with the risk of prostate cancer? Prospective results from the Massachusetts Male Aging Study

OBJECTIVES

To determine whether prediagnostic serum hormones are predictive of prostate cancer risk in a sample of men 40 to 70 years old at baseline.

METHODS

Seventeen serum hormones, including androgens, estrogens, and adrenal and pituitary hormones, were measured at baseline (1987 to 1989) and used to predict incident prostate cancer by follow-up (1995 to 1997) using data from the Massachusetts Male Aging Study, a prospective, population-based random sample.

RESULTS

Seventy men (4%) of 1576 were diagnosed with prostate cancer between the baseline and follow-up periods (approximately 8 years). None of the hormones were associated with prostate cancer risk except for androstanediol glucuronide (AAG), which exhibited a nonlinear, inverse relationship with prostate cancer (P <0.003) when age, body mass index, alcohol use, dihydrotestosterone, and total prostate-specific antigen were controlled for. Men in the second, third, and fourth quartiles of AAG relative to the first were less likely to be diagnosed with prostate cancer, although only the comparison of the second versus the first achieved statistical significance (odds ratio 0.2, 99% confidence interval 0.04 to 0.6). No dose-response relationships were observed.

CONCLUSIONS

The lack of association with most hormones and the nonlinear association with AAG calls into question whether serum hormones collected during midlife are risk factors for prostate cancer.

Regional variations of insulin-like growth factor I (IGF-I), IGF-II, and receptor type I in benign prostatic hyperplasia tissue and their correlation with intraprostatic androgens

Benign prostatic hyperplasia (BPH) is an androgen-dependent disease; it originates exclusively in the inner prostate, which includes tissue surrounding the urethra. Stromal-epithelial interaction has a pivotal role in the regulation of the development and growth of the prostate, and locally produced peptide growth factors are considered important mediators of this interaction. Insulin-like growth factor I (IGF-I) and IGF-II, acting mainly through type 1 IGF receptor (IGFR1), have mitogenic and antiapoptotic effects on epithelial and stromal prostatic cells. In this study the expression of IGF-I, IGF-II, and IGFR1 messenger ribonucleic acid (mRNA), the immunoreactive content of IGF-I (irIGF-I) and IGF-II (irIGF-II) were determined in periurethral, intermediate, and subcapsular regions of BPH tissue to verify their possible regional variation; a correlation to the tissue levels of dihydrotestosterone (DHT) and 3 alpha-androstanediol (3 alpha Diol) was also determined to verify their possible androgen dependence. Prostates were removed by suprapubic prostatectomy from 14 BPH patients and sectioned in the periurethral, intermediate, and subcapsular regions. Gene expression of IGF-I, IGF-II, and IGFR1 was evaluated by semiquantitative RT-PCR, using beta-actin as a control. irIGF-I was measured by RIA, and irIGF-II was measured by IRMA after acidification and chromatography on Sep-Pak C(18) cartridges. DHT and 3 alpha Diol concentrations were evaluated by RIA after extraction and purification on Celite microcolumns. IGF-II and IGFR1, but not IGF-I, mRNA was higher in the periurethral than in the intermediate (P < 0.05) and subcapsular (P < 0.01) region. Also, prostatic levels of irIGF-II, expressed as picomoles per g tissue, were higher in the periurethral (20.84 +/- 1.84) than in the intermediate (14.81 +/- 2.11; P < 0.05) and subcapsular (10.88 +/- 1.21; P < 0.001) region. No significant differences were found in irIGF-I content. Considering prostatic androgen levels, DHT and 3alphaDiol presented a regional variation, with the highest concentrations in the periurethral region. IGF-II mRNA and irIGF-II levels were positively correlated with both DHT and 3 alpha Diol content. These results demonstrate that in BPH tissue a greater IGF-II activity is present in the periurethral region, the site of origin of BPH. Moreover, we can hypothesize that the tissue androgen content may modulate prostatic production of IGF-II, acting at the transcriptional and probably the posttranscriptional level. Therefore, even though further studies will need to confirm this hypothesis, DHT may increase IGF-II activity, mainly in the periurethral region, which, in turn, induces, through IGFR1, benign proliferation of both epithelial and stromal cells, characteristic of BPH.

Prostate-specific antigen and human glandular kallikrein 2 are markedly elevated in urine of patients with polycystic ovary syndrome

Prostate-specific antigen (PSA) is a well-established tumor marker of prostatic adenocarcinoma. Human glandular kallikrein 2 (hK2), another serine protease closely related to PSA, is also gaining ground as a promising diagnostic tool in prostate cancer. The expression of these 2 proteases is known to be regulated by androgens and progestins in hormonally responsive tissues, such as the male prostate and the female breast. Previously, we have shown that serum PSA levels in normal women are very low but still detectable by ultrasensitive PSA immunoassays. We have also demonstrated that some women with hyperandrogenic syndromes have elevated serum PSA levels. In this study, we have measured urinary PSA and urinary hK2 levels in 35 polycystic ovary syndrome (PCOS) patients and compared them to those of 41 age-matched controls. We found that urinary PSA levels were significantly higher (P < 0.0001) in PCOS patients (mean +/- SE = 820 +/- 344 ng/L) than in the controls (mean +/- SE = 4.3 +/- 1.8 ng/L). Similarly, the difference between urinary hK2 of patients (mean +/- SE = 8.2 +/- 3.1 ng/L) and controls (0.5 +/- 0.3 ng/L) was also significant (P < 0.001). A weak correlation was observed between urinary PSA and serum 3 alpha-androstanediol glucuronide (r(s) = 0.42, P = 0.03) as well as between urinary PSA and serum testosterone (r(s) = 0.40, P = 0.04). The results of this study indicate that urinary PSA, and possibly urinary hK2, are promising markers of hyperandrogenism in females suffering from PCOS.

Evidence for significant differences in microsomal drug glucuronidation by canine and human liver and kidney

The in vitro glucuronidation of a range of structurally diverse chemicals has been studied in hepatic and renal microsomes from human donors and the beagle dog. These studies were undertaken to improve on the limited knowledge of glucuronidation by the dog and to assess its suitability as a model species for pharmacokinetic studies. In general, the compounds studied were glucuronidated severalfold more rapidly (based on intrinsic clearance estimates) by DLM than by HLM. Intrinsic clearance values for human UGT1A1 and UGT2B7 substrates were an order of magnitude higher in DLM than in HLM (e.g., gemfibrozil: 31 microl/min/mg versus 3.0 microl/min/mg; ketoprofen: 2.4 microl/min/mg versus 0.2 microl/min/mg). There were also drug-specific differences. HLM readily glucuronidated propofol (2.4 microl/min/mg) whereas DLM appeared unable to glucuronidate this drug directly. Regioselective differences in morphine glucuronidation were also apparent. Human kidney microsomes catalyzed the glucuronidation of many xenobiotics, although glucuronidation of the endobiotic bilirubin was not detectable in this tissue. In direct contrast, dog kidney microsomes glucuronidated bilirubin only (no glucuronidation of all other xenobiotics was detected). These preliminary studies indicated significant differences in the glucuronidation of xenobiotics by microsomes from the livers and kidneys of human and dog and should be confirmed using a larger panel of tissues from individual dogs. Early knowledge of the relative rates of in vitro glucuronidation, the UGTs responsible for drug glucuronidation, and their tissue distribution in different species could assist the design and analysis of preclinical pharmacokinetic and safety evaluation studies.

Role of androgens in female-pattern androgenetic alopecia, either alone or associated with other symptoms of hyperandrogenism

The roles of androgen hypersecretion, in situ enzyme activity, and androgen receptors in androgenetic alopecia in women are still a matter of debate. We studied 187 women with alopecia, which we graded I, II, or III, according to Ludwig's classification, and 21 healthy control women. All participants were subjected to full basal and 1 h post-beta-1-24 corticotropin stimulation endocrine profiles. Abnormal hormone profiles were observed in 67% of the patients with alopecia alone (group A, n = 110) and in 84% of the patients with alopecia plus other symptoms of hyperandrogenism including acne, hirsutism, and menstrual cycle disturbances (group B, n = 77). Mean serum 5alpha-androstane-3alpha,17beta-diol glucuronide (3alpha-AdiolG) levels in all three patient groups (6.50+/-4.10, 8.90+/-5.80, and 14.70+/-8.90 nmol/l, respectively) correlated with the grade of alopecia (I-III) and were significantly higher than in the control group (4.80+/-2.05 nmol/l, P < 0.005). Mean serum sex hormone-binding globulin (SHBG) levels were inversely correlated with the grade of alopecia (I-III) and were significantly lower in all three patient groups (50.55+/-23.50, 40.00+/-17.65, and 38.80+/-14.10 nmol/l, respectively) than in the control group (61.15+/-17.65 nmol/l, P < 0.05). Mean serum levels of delta4-androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and 3alpha-AdiolG were higher in group B than in group A, and higher in group A than in the control group. The significant correlations found between adrenal secretion - either positive (with 3alpha-AdiolG levels and the body mass index) or negative (with SHBG levels) - might reflect the important contribution of secretory and metabolic components in the development of alopecia, the severity of which has been shown to be very closely related to observed levels of two of these parameters (3alpha-AdiolG and SHBG).

Effects of replacing meat with soyabean in the diet on sex hormone concentrations in healthy adult males

A randomised crossover dietary intervention study was performed to evaluate the effects of replacing meat protein in the diet with a soyabean product, tofu, on blood concentrations of testosterone, dihydrotestosterone, androstanediol glucuronide, oestradiol, sex hormone-binding globulin (SHBG), and the free androgen index (total testosterone concentration/SHBG concentration x 100; FAI). Forty-two healthy adult males aged 35-62 years were studied. Diets were isoenergetic, with either 150 g lean meat or 290 g tofu daily providing an equivalent amount of macronutrients, with only the source of protein differing between the two diets. Each diet lasted for 4 weeks, with a 2-week interval between interventions. Fasting blood samples were taken between 07.00 and 09.30 hours. Urinary excretion of genistein and daidzein was significantly higher after the tofu diet (P < 0.001). Blood concentrations of sex hormones did not differ after the two diets, but the mean testosterone:oestradiol value was 10% higher (P = 0.06) after the meat diet. SHBG was 3% higher (P = 0.07), whereas the FAI was 7% lower (P = 0.06), after the tofu diet compared with the meat diet. There was a significant correlation between the difference in SHBG and testosterone:oestradiol and weight change. Adjusting for weight change revealed SHBG to be 8.8% higher on the tofu diet (mean difference 3 (95% CI 0.7, 5.2) nmol/l; P = 0.01) and testosterone:oestradiol to be significantly lower, P = 0.049). Thus, replacement of meat protein with soyabean protein, as tofu, may have a minor effect on biologically-active sex hormones, which could influence prostate cancer risk. However, other factors or mechanisms may also be responsible for the different incidence rates in men on different diets.

Hormones and diet: low insulin-like growth factor-I but normal bioavailable androgens in vegan men

Mean serum insulin-like growth factor-I was 9% lower in 233 vegan men than in 226 meat-eaters and 237 vegetarians (P = 0.002). Vegans had higher testosterone levels than vegetarians and meat-eaters, but this was offset by higher sex hormone binding globulin, and there were no differences between diet groups in free testosterone, androstanediol glucuronide or luteinizing hormone.

Function of human brain short chain L-3-hydroxyacyl coenzyme A dehydrogenase in androgen metabolism

Human brain short chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD) has been demonstrated to be a unique 3alpha-hydroxysteroid dehydrogenase (HSD) that can convert 5alpha-androstane-3alpha, 17beta-diol (3alpha-adiol) to dihydrotestosterone (DHT), whose affinity to the androgen receptor is 10(5)-fold higher than that of 3alpha-adiol. The catalytic efficiency of human SCHAD for this oxidative 3alpha-HSD reaction was estimated to be 164 min(-1) mM(-1), about 10-fold higher than that measured for the backward reaction. Thus, human brain SCHAD may function in androgen metabolism as a new kind of 3alpha-HSD by counteracting all other known 3alpha-HSDs, which would unidirectionally catalyze the reduction of DHT to the almost inactive 3alpha-adiol. Human SCHAD is identical to an amyloid-beta binding protein (ERAB) involved in Alzheimer's disease, which was previously reported to be associated with the endoplasmic reticulum. This protein is, in fact, localized in mitochondria, not endoplasmic reticulum, as evidenced by immunocytochemical studies and its noncleavable mitochondrial targeting sequence and lack of endoplasmic reticulum targeting signals or transmembrane segments. These results prompt the suggestion that the mitochondrion plays not only an essential role in the initial step of steroidogenesis, but also important roles in the intracellular homeostasis of sex steroid hormones. Northern blot analysis revealed that the human SCHAD gene is expressed in both gonadal and peripheral tissues including the prostate whose growth notably requires DHT, the most potent androgen. This study represents the first report of a 3alpha-HSD that could act to generate DHT from 3alpha-adiol and thereby maintain intracellular DHT levels. We propose that inhibitors of the 3alpha-HSD activity of human brain SCHAD could be useful for the treatment of benign prostatic hyperplasia and other disorders involving DHT metabolism, in combination with known inhibitors of steroid 5alpha-reductases.

Changes in the metabolic elimination profile of testosterone following exposure of the crustacean Daphnia magna to tributyltin

The biocide tributyltin has been found to cause the development of pseudohermaphroditic conditions in some neogastropod species. These abnormalities of the reproductive system have adversely affected the fecundity of some field populations of gastropods, resulting in local population declines. Current evidence suggests that tributyltin elicits these effects by interfering with the biotransformation of testosterone to other steroid derivatives, resulting in an elevation in endogenous testosterone or some of its bioactive derivatives. The purpose of the present study was to determine whether tributyltin altered testosterone metabolism in daphnids (Daphnia magna), a species commonly used in ecotoxicology testing. Exposure of daphnids to 1.2 microg (tin)/L caused a general increase in the rate of elimination of oxido-reduced, hydroxylated, and glucose-conjugated derivatives of testosterone. However, tributyltin exposure had no significant effect on the rate of elimination of the glucose-conjugated forms of the various oxido-reduced and hydroxylated derivatives of testosterone. As a result, the percentage of the oxido-reduced and hydroxylated metabolites of testosterone eliminated as glucose conjugates decreased with increasing tributyltin exposure levels. These results demonstrate that tributyltin causes alterations in testosterone metabolism in daphnids that would result in an increase in the production of oxido-reduced derivatives. These products are preferentially retained in the tissues of daphnids and are variously androgenic in vertebrates. The increased production of oxido-reduced derivatives of testosterone may be mechanically responsible for the masculinizing effects of tributyltin in some species and suggests that daphnids may be a suitable surrogate for evaluating the potential of chemicals to elicit this form of toxicity.