C19‐5‐ene Steroids in Nature

Impact of Gestational and Postmenstrual Age on Excretion of Fetal Zone Steroids in Preterm Infants Determined by Gas Chromatography-Mass Spectrometry

CONTEXT

Fetal zone steroids (FZSs) are excreted in high concentrations in preterm infants. Experimental data suggest protective effects of FZSs in models of neonatal disease.

OBJECTIVE

We aimed to characterize the postnatal FZS metabolome of well preterm and term infants.

METHODS

Twenty-four-hour urinary FZS excretion rates were determined in early preterm (<30 weeks' gestation), preterm (30-36 weeks), and term (>37 weeks) infants. Pregnenolone and 17-OH-pregnenolone metabolites (n = 5), and dehydroepiandrosterone sulfate and metabolites (n = 12) were measured by gas chromatography mass spectrometry. Postnatal concentrations of FZSs were compared with already published prenatal concentrations in amniotic fluid.

RESULTS

Excretion rates of total FZSs and most of the single metabolites were highest in early preterm infants. In this group, excretion rates approach those of term infants at term equivalent postmenstrual age. Preterm infants of 30-36 weeks had more than half lower median excretion rates of FZSs than early preterm infants at the same time of postmenstrual age. Postnatal concentrations of FZSs were partly more than 100-fold higher in all gestational age groups than prenatal concentrations in amniotic fluid at midgestation.

CONCLUSION

The excretion rates of FZSs as a proxy of the involution of the fetal zone of the most immature preterm infants approached those of term infants at term equivalent. In contrast, the fetal zone in more mature preterm infants undergoes more rapid involution. These data in exclusively well neonates can serve as a basis to investigate the effects of illness on the FZS metabolome in future studies.

Comparison of dehydroepiandrosterone (DHEA) and pregnanolone with existing pharmacotherapies for alcohol abuse on ethanol- and food-maintained responding in male rats

The present study compared two putative pharmacotherapies for alcohol abuse and dependence, dehydroepiandrosterone (DHEA) and pregnanolone, with two Food and Drug Administration (FDA)-approved pharmacotherapies, naltrexone and acamprosate. Experiment 1 assessed the effects of different doses of DHEA, pregnanolone, naltrexone, and acamprosate on both ethanol- and food-maintained responding under a multiple fixed-ratio (FR)-10 FR-20 schedule, respectively. Experiment 2 assessed the effects of different mean intervals of food presentation on responding for ethanol under a FR-10 variable-interval (VI) schedule, whereas Experiment 3 assessed the effects of a single dose of each drug under a FR-10 VI-80 schedule. In Experiment 1, all four drugs dose-dependently decreased response rate for both food and ethanol, although differences in the rate-decreasing effects were apparent among the drugs. DHEA and pregnanolone decreased ethanol-maintained responding more potently than food-maintained responding, whereas the reverse was true for naltrexone. Acamprosate decreased responding for both reinforcers with equal potency. In Experiment 2, different mean intervals of food presentation significantly affected the number of food reinforcers obtained per session; however, changes in the number of food reinforcements did not significantly affect responding for ethanol. Under the FR-10 VI-80 schedule in Experiment 3, only naltrexone significantly decreased both the dose of alcohol presented and blood ethanol concentration (BEC). Acamprosate and pregnanolone had no significant effects on any of the dependent measures, whereas DHEA significantly decreased BEC, but did not significantly decrease response rate or the dose presented. In summary, DHEA and pregnanolone decreased ethanol-maintained responding more potently than food-maintained responding under a multiple FR-10 FR-20 schedule, and were more selective for decreasing ethanol self-administration than either naltrexone or acamprosate under that schedule. Experiment 2 showed that ethanol intake was relatively independent of the interval of reinforcement in the food-maintained component, and Experiment 3 showed that naltrexone was the most effective drug at the doses tested when the interval for food reinforcement was low and maintained under a variable-interval schedule.

Steroid sulfatase mediated growth Sof human MG-63 pre-osteoblastic cells

Estrogen plays an important role in maintaining bone density. Postmenopausal women have low plasma estrogen, but have high levels of conjugated steroids, particularly estrone sulfate (E1S) and dehydroepiandrosterone sulfate (DHEAS). Conversion of these precursors to active estrogens may help maintain bone density in postmenopausal women. The enzyme steroid sulfatase (STS) converts sulfated steroids into active forms in peripheral tissues. STS occurs in bone, but little is known about its role in bone function. In this study, we investigated STS activity and expression in the human MG-63 pre-osteoblastic cell line. We also tested whether sulfated steroids can stimulate growth of these cells. MG-63 cells and microsomes both possessed STS activity, which was blocked by the STS inhibitors EMATE and 667 Coumate. Further evidence for STS in these cells was provided by RT-PCR, using STS specific primers, which resulted in cDNA products of the predicted size. We then tested for growth of MG-63 cells in the presence of estradiol-17β, E1S and DHEAS. All three steroids stimulated MG-63 cell growth in a steroid-free basal medium. We also tested whether the cell growth induced by sulfated steroids could be blocked using a STS inhibitor (667 Coumate) or using an estrogen receptor blocker (ICI 182,780). Both compounds inhibited E1S-induced cell growth, indicating that E1S stimulates MG-63 cell growth through a mechanism involving both STS and the estrogen receptor. Finally, we demonstrated using RT-PCR that MG-63 cells contain mRNA for both estrogen receptor alpha and estrogen receptor beta. Our data reveal that STS is present in human pre-osteoblastic bone cells and that it can influence bone cell growth by converting inactive sulfated steroids to estrogenic forms that act via estrogen receptor alpha or beta.

Characterization of steroid sulfatase in the MC3T3-E1 mouse pre-osteoblastic cell line

Regulation of bone density is partly dependent upon steroid hormones, with estrogens playing an important role. Inactive conjugated estrogens may serve as precursors to active estrogens, especially in post-menopausal women, via steroid sulfatase, which converts conjugated estrogens into unconjugated estrogens. The purpose of this study was to characterize steroid sulfatase in the MC3T3-E1 mouse pre-osteoblastic cell line. Enzyme conversion assays were performed on whole MC3T3-E1 cells in culture and on microsomes prepared by differential centrifugation. (3)H-E(1)S and (3)H-DHEAS were used as tracers, and radioinert E(1)S and DHEAS were used as substrate. Whole cells and microsomes exhibited steroid sulfatase activity, which was blocked by the specific inhibitor estrone-3-O-sulfamate (EMATE). The K(m) of steroid sulfatase in microsomes averaged 83 μM when using E(1)S as substrate and 64 μM when using DHEAS. Western blotting of MC3T3-E1 microsomes for steroid sulfatase was performed, after SDS-PAGE, using an antibody generated against a peptide based on a conserved region of steroid sulfatase. Western blotting revealed three bands of cross-reactivity, ranging from 50 to 79 kDa. Reverse transcriptase polymerase chain reaction (RT-PCR), using specific primers, resulted in a single cDNA band of the expected size (100 bp) and sequence, indicating the presence of steroid sulfatase mRNA. Growth assays revealed that the MC3T3-E1 cells were stimulated by estradiol-17β, and also by estrone sulfate and DHEAS, revealing that the cells can use steroid sulfatase to produce active estrogens. Furthermore, growth of these cells in the presence of estradiol, estrone and estrone sulfate was inhibited by the estrogen receptor blocker ICI 182,780, indicating that stimulation of cell growth is mediated by the estrogen receptor. In our studies, four lines of evidence (enzyme activity, immunoassay, RT-PCR and growth assays) demonstrated the presence of steroid sulfatase in mouse MC3T3-E1 bone cells. The existence of steroid sulfatase in these pre-osteoblastic cells, along with the ability of sulfated steroids to promote their growth, suggest the possibility that this enzyme is involved in regulation of bone density in mice.

Effects of 7-keto dehydroepiandrosterone on voluntary ethanol intake in male rats

Administration of dehydroepiandrosterone (DHEA), a neurosteroid that can negatively modulate the GABA A receptor, has been shown to decrease voluntary intake of ethanol in rats. In vivo, DHEA can be metabolized to a variety of metabolites, including 3β-acetoxyandrost-5-ene-7,17-dione (7-keto DHEA), a metabolite without the prohormonal effects of DHEA. This study compared the effectiveness of 7-keto DHEA with DHEA for reducing ethanol intake in the same group of rats. The subjects, previously trained to drink ethanol using a saccharin-fading procedure, had access to ethanol for 30 min daily and the amount consumed was recorded. Subjects were administered 10 and 56 mg/kg of DHEA or 7-keto DHEA intraperitoneally 15 min before drinking sessions. Subjects received each particular dose daily until one of two criteria was met, that is, either ethanol intake did not differ by more than 20% of the mean for 3 consecutive days or for a maximum of 8 days. Both 10 and 56 mg/kg of 7-keto DHEA significantly reduced the dose of ethanol consumed. Although 10mg/kg of 7-keto DHEA produced decreases similar to those found with DHEA, the 56-mg/kg dose of 7-keto DHEA was significantly more effective at decreasing the dose of ethanol consumed than the same dose of DHEA. These results show that 7-keto DHEA is comparable with, or possibly more effective than, DHEA at decreasing ethanol consumption in rats, and that 7-keto DHEA is a compound deserving further investigation as a possible clinical treatment for alcohol abuse without the prohormonal effects of DHEA.

A potential role for 5-androstene-3β,7β,17β-triol in obesity and metabolic syndrome

Metabolic syndrome is marked by perturbed glucocorticoid (GC) signaling, systemic inflammation, and altered immune status. Dehydroepiandrosterone (DHEA), a major circulating adrenal steroid and dietary supplement, demonstrates antiobesity, anti-inflammatory, GC-opposing and immune-modulating activity when administered to rodents. However, plasma DHEA levels failed to correlate with metabolic syndrome and oral replacement therapy provided only mild benefits to patients. Androstene-3β,7β,17β-triol (β-AET) an anti-inflammatory metabolite of DHEA, also exhibits GC-opposing and immune-modulating activity when administered to rodents. We hypothesized a role for β-AET in obesity. We now report that plasma levels of β-AET positively correlate with BMI in healthy men and women. Together with previous studies, the observations reported here may suggest a compensatory role for β-AET in preventing the development of metabolic syndrome. The β-AET structural core may provide the basis for novel pharmaceuticals to treat this disease.

New insights into the protective effects of DHEA1)

Numerous studies investigated the effects of pharmacological doses of DHEA in animals. Among protective effects, antiglucocorticoid potencies, triggering and modulation of immunity and anticancerous effects were reported. Because DHEA levels decrease in aging humans, this steroid has been assayed as replacement therapy in elderly volunteers without striking evidence for beneficial effects. Examination of the investigations carried out in animals lead to suspect that, rather than DHEA, its metabolites produced in tissues could be responsible for some of the observed effects. Known as the "mother steroid", DHEA is a precursor for androgenic and estrogenic steroid hormones. In addition, DHEA is hydroxylated at the 7α position by the cytochrome P450 7B1 (CYP7B1), and the 7α-hydroxy-DHEA produced is a substrate for the 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) which converts it into 7β-hydroxy-DHEA. Both 7-hydroxylated metabolites were shown to favor the onset of immunity in mice and the activation of memory T cells in humans. Other DHEA and testosterone-derived metabolites, namely epiandrosterone and 5α-androstane-3β,17β-diol, are also substrates for the CYP7B1 and their 7α-hydroxylated products were also converted into the 7β epimer by the 11β-HSD1. When assayed at doses 104 lower than DHEA, 7β-hydroxy-epiandrosterone was shown to shift the prostaglandin metabolism patterns from prostaglandin E2 (PGE2) to PGD2 production, thus triggering the resolution of inflammation. In addition, 7β-hydroxy-epiandrosterone (1 nM) exerted the same effects as tamoxifen (1 μM) on the proliferation of MCF-7 and MDA-231 human breast cancer cells. These findings suggest that the observed effects of 7β-hydroxy-epiandrosterone could be mediated by estrogen receptors. This overview of recent research implies that DHEA does not act directly and that its effects are due to its metabolites when produced in tissues. Treatments with DHEA should take into account the target tissue abilities to produce the desired metabolites through the two key enzymes, CYP7B1 and 11β-HSD1.

5-Androstene-3β,7β,17β-triol (β-AET) slows thermal injury induced osteopenia in mice: relation to aging and osteoporosis

5-androstene-3β,7β,17β-triol (β-AET), an active metabolite of dehydroepiandrosterone (DHEA), reversed glucocorticoid (GC)-induced suppression of IL-6, IL-8 and osteoprotegerin production by human osteoblast-like MG-63 cells and promoted osteoblast differentiation of human mesenchymal stem cells (MSCs). In a murine thermal injury model that includes glucocorticoid-induced osteopenia, β-AET significantly (p<0.05) preserved bone mineral content, restored whole body bone mineral content and endochondral growth, suggesting reversal of GC-mediated decreases in chondrocyte proliferation, maturation and osteogenesis in the growth plate. In men and women, levels of β-AET decline with age, consistent with a role for β-AET relevant to diseases associated with aging. β-AET, related compounds or synthetic derivatives may be part of effective therapeutic strategies to accelerate tissue regeneration and prevent or treat diseases associated with aging such as osteoporosis.

Comparison of the effects of dietary protein, androstenediol and forearm muscle area on radial bone variables in healthy prepubertal children

Adequate dietary habits are supposed to be one of the most important modifiable factors in osteoporosis prevention. However, the importance of specific nutrients is controversial. We examined relevant nutrients which are supposed to have an impact on bone parameters and compared their effect sizes with those of two known predictors of bone development: bone-related muscle mass and androgen levels. We analysed nutritional, hormonal and anthropometric data from 107 prepubertal children participating in the Dortmund Nutritional and Anthropometric Longitudinally Designed Study. Diaphyseal bone mineral content (BMC), cortical area (CA), periosteal circumference, strength strain index and muscle area of the non-dominant forearm were measured by peripheral quantitative computed tomography. Data on long-term nutrient intakes (e.g. protein, Ca and vitamin D) were derived from 3 d weighed dietary records. Twenty-four hour urinary excretion rates of androgen metabolites including the sex steroid androstenediol were measured using GC-MS. Of all considered nutrients, only protein showed a trend for an association with BMC (β = +0·11; P = 0·073) and CA (β = +0·11; P = 0·056) in stepwise linear regression models. None of the other considered dietary variables was associated with bone parameters. The size of the bone anabolic effect of protein was partly comparable with that of androstenediol. Even though boys gained more bone mass in comparison with girls, the protein effect did not differ between sexes. Bone-related muscle area and sex steroids have the strongest effects on prepubertal diaphyseal bone. However, dietary protein may have a similar bone anabolic influence compared with androstenediol. In children without explicit nutrient deficits, protein seems to be the most important dietary component for diaphyseal bone status.

A new antidiabetic compound attenuates inflammation and insulin resistance in Zucker diabetic fatty rats

Tissue macrophage inflammatory pathways contribute to obesity-associated insulin resistance. Here, we have examined the efficacy and mechanisms of action of a novel anti-inflammatory compound (HE3286) in vitro and in vivo. In primary murine macrophages, HE3286 attenuates LPS- and TNFalpha-stimulated inflammation. In Zucker diabetic fatty rats, inflammatory cytokine/chemokine expression was downregulated in liver and adipose tissue by HE3286 treatment, as was macrophage infiltration into adipose tissue. In line with reduced inflammation, HE3286 treatment normalized fasting and fed glucose levels, improved glucose tolerance, and enhanced skeletal muscle and liver insulin sensitivity, as assessed by hyperinsulinemic euglycemic clamp studies. In phase 2 clinical trials, HE3286 treatment led to an enhancement in insulin sensitivity in humans. Gluconeogenic capacity was also reduced by HE3286 treatment, as evidenced by a reduced glycemic response during pyruvate tolerance tests and decreased basal hepatic glucose production (HGP) rates. Since serum levels of gluconeogenic substrates were decreased by HE3286, it indicates that the reduction of both intrinsic gluconeogenic capacity and substrate availability contributes to the decrease in HGP. Lipidomic analysis revealed that HE3286 treatment reduced liver cholesterol and triglyceride content, leading to a feedback elevation of LDL receptor and HMG-CoA reductase expression. Accordingly, HE3286 treatment markedly decreased total serum cholesterol. In conclusion, HE3286 is a novel anti-inflammatory compound, which displays both glucose-lowering and cholesterol-lowering effects.

Prepubertal healthy children's urinary androstenediol predicts diaphyseal bone strength in late puberty

CONTEXT

During the physiological process of adrenarche, the adrenal glands of healthy children secrete increasing amounts of weak androgenic steroids partly metabolized to potent sex steroids.

OBJECTIVE

The aim of the study was to examine whether adrenal androgen metabolite excretion rates before the onset of puberty may be prospectively associated with late-pubertal diaphyseal bone strength.

SETTING

We conducted the study in an auxological and metabolic child nutrition research facility.

STUDY POPULATION AND DESIGN

The sample included 45 healthy adolescents who underwent proximal forearm bone and muscle area measurements by peripheral quantitative computed tomography at the age of 16 yr (SD 1.5) and who had collected a 24-h urine sample 8 yr earlier, allowing to quantify the prepubertal urine metabolome. Prepubertal hormonal predictors quantified by gas chromatography-mass spectrometry were: dehydroepiandrosterone, its 16-hydroxylated downstream metabolites, 5-androstene-3beta,17beta-diol (androstenediol), sums of total androgen and glucocorticoid metabolites, cortisol, and 6beta-hydroxycortisol.

MAIN OUTCOMES

Proximal forearm radius was measured.

RESULTS

Of all prepubertal hormones analyzed, only sex- and age-specific androstenediol levels significantly predicted pubertal stage-, height-, and muscularity-adjusted diaphyseal bone modeling (periosteal circumference, beta = 0.67, P = 0.002; cortical area, beta = 2.15, P = 0.02), bone mineral content (beta = 2.2; P = 0.04), and polar strength strain index (beta = 12.2; P = 0.002). Androstenediol explained 5-10% of the late-pubertal diaphyseal radius variability.

CONCLUSIONS

Our prospective profiling of urinary steroid metabolites in 24-h urine samples collected before puberty suggests that androstenediol is an early predictor of the diaphyseal bone strength in late puberty. This predominantly peripheral conversion product of adrenarchal dehydroepiandrosterone by 17beta-hydroxysteroid dehydrogenase may hence be involved in a sustained improvement of radial bone accretion during growth.

A novel radioimmunoassay of 16alpha-hydroxy-dehydroepiandrosterone and its physiological levels

16alpha-Hydroxy-dehydroepiandrosterone (16alpha-OH-DHEA) belongs to the products of extensive DHEA metabolism in mammalian tissues. It is a precursor of 16alpha-hydroxylated estrogens, increased levels of which are associated with autoimmune disorders. A highly specific radioimmunoassay of unconjugated 16alpha-OH-DHEA was developed and evaluated. Polyclonal rabbit antisera were raised against 3beta,16alpha-dihydroxy-17,19-dione-19-O-(carboxymethyloxime) and 3beta,16alpha-dihydroxy-7,17-dione-7-O-(carboxymethyloxime) BSA conjugates. Two methods were used for preparation of the conjugates. Homologous radioiodinated derivatives with tyrosine methyl ester were prepared as tracers. While antisera to 7-CMO cross-reacted with DHEA as much as by 58%, the cross-reaction of the chosen antiserum prepared via 19-oxogroup by micellar conjugation technique with 16beta-OH-DHEA was only 0.13% and with all other structurally related steroids, including DHEA were lower than 0.01%. The detection limit was 0.017 pmol (5.7 pg)/tube, the average intra- and inter-assay coefficients of variation were 8.2 and 11.4%, respectively. Mean recovery of serum spiked with 16alpha-OH-DHEA varied between 80 and 110%, the results were independent on sample dilution. 16alpha-OH-DHEA concentrations in 18 randomly selected sera, including 6 samples from patients with thyroid cancer were compared with results obtained by earlier GC-MS method. Physiological levels of 16alpha-OH-DHEA in 316 sera (184 females and 132 males) analyzed so far varied between 0.0 and 1.86 nmol/l.

A novel radioimmunoassay of 7-oxo-DHEA and its physiological levels

A novel radioimmunoassay (RIA) of unconjugated 7-oxo-dehydroepiandrosterone (7-oxo-DHEA) in human serum was developed for the first time. This steroid is an intermediate in the biosynthesis of immunomodulatory 7-hydroxylated DHEA metabolites, and has been shown to possess thermogenic properties. The method employs polyclonal rabbit antiserum to (19E)-3beta-hydroxy-7,17,19-trione-19-O-(carboxymethyloxime):BSA conjugate and a homologous radioiodinated derivative with tyrosine methyl ester. The cross reactivity of the antiserum with structurally closest 7-hydroxyepimers of DHEA was lower than 1.7%, with DHEA 0.4%, with all other related steroid less than 0.4%. The method includes ether extraction of serum (0.5 ml), followed by RIA. Its detection limit was 0.06 pmol (18 pg)/tube, the average intra- and inter-assay coefficients of variation were 4.1% and 8.3%, respectively. Mean recovery of serum spiked with 7-oxo-DHEA varied between 78.8% and 112%. Its levels in three serum pools were compared with a low-resolution gas chromatography-mass spectrometry method with satisfactory results. The method has been used for determination of 7-oxo-DHEA in serum samples of 215 subjects (91 males and 124 females) without overt endocrine disorders, aged 5-71 years. The over-all mean+/-S.D. was 0.280+/-0.227, the median 0.239 nmol/l. No significant sex differences were recorded. The only group which differed significantly from all other ones were males below 10 years, significantly lower values than in other age groups were found also in the first two age groups of females.

C19-Steroids as androgen receptor modulators: Design, discovery, and structure-activity relationship of new steroidal androgen receptor antagonists

Dehydroepiandrosterone (DHEA), the most abundant steroid in human circulating blood, is metabolized to sex hormones and other C19-steroids. Our previous collaborative study demonstrated that androst-5-ene-3beta,17beta-diol (Adiol) and androst-4-ene-3,17-dione (Adione), metabolites of DHEA, can activate androgen receptor (AR) target genes. Adiol is maintained at a high concentration in prostate cancer tissue; even after androgen deprivation therapy and its androgen activity is not inhibited by the antiandrogens currently used to treat prostate cancer patients. We have synthesized possible metabolites of DHEA and several synthetic analogues and evaluated their role in androgen receptor transactivation to identify AR modulators. Steroids with low androgenic potential in PC-3 cell lines were evaluated for anti-dihydrotestosterone (DHT) and anti-Adiol activity. We discovered three potent antiandrogens: 3beta-acetoxyandrosta-1,5-diene-17-one 17-ethylene ketal (ADEK), androsta-1,4-diene-3,17-dione 17-ethylene ketal (OAK), and 3beta-hydroxyandrosta-5,16-diene (HAD) that antagonized the effects of DHT as well as of Adiol on the growth of LNCaP cells and on the expression of prostate-specific antigen (PSA). In vivo tests of these compounds will reveal their potential as potent antiandrogens for the treatment of prostate cancer.

The native anti-glucocorticoid paradigm

Circulating 3beta-hydroxysteroids including dehydroepiandrosterone (DHEA) are 7alpha-hydroxylated by the cytochrome P450-7B1 in the liver, skin and brain, which are the target organs of glucocorticoids. Anti-glucocorticoid effects with 7alpha-hydroxy-DHEA were observed in vivo without an interference with glucocorticoid binding to its receptor. In the organs mentioned above, the circulating inactive cortisone was reduced into active cortisol by the 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1). We demonstrated that 7alpha-hydroxy-DHEA was also a substrate for this enzyme. Studies of the 11beta-HSD1 action on 7alpha-hydroxy-DHEA showed the reversible production of 7beta-hydroxy-DHEA through an intermediary 7-oxo-DHEA, and the kinetic parameters favored this production over that of active glucocorticoids. Both the production of 7alpha-hydroxysteroids and their interference with the activation of cortisone into cortisol are basic to the concept of native anti-glucocorticoids efficient at their production site. This opens a promising new area for research.