Inhibition of human and rat 11β-hydroxysteroid dehydrogenases activities by bisphenol A

Impact of isothiazolinone biocides on gonadal steroid production: Focus on 3β-hydroxysteroid dehydrogenase inhibition

Isothiazolinone biocides have been widely used as disinfectants during the COVID-19 pandemic. However, their effects on gonadal steroidogenesis remain unclear. This study investigated the endocrine-disrupting potential of isothiazolinone biocides, focusing on their inhibition of gonadal 3β-hydroxysteroid dehydrogenases (3β-HSDs). Enzymatic assays, molecular docking, and 3D-QSAR analyses evaluated the impact of seven isothiazolinones on human KGN cell 3β-HSD2 (h3β-HSD2) and rat testicular 3β-HSD1 (r3β-HSD1). Dichlorooctylisothiazolinone, butylbenzo[d]isothiazol-3(2 H)-one, octylisothiazolinone, and benzisothiazolinone inhibited h3β-HSD2 with IC50 values of 4.02, 15.35, 12.12, and 30.55 μM, respectively. These compounds also inhibited r3β-HSD1 with IC50 values of 1.67, 16.51, 13.25, and 29.28 μM, respectively. Whereas, methylchloroisothiazolinone selectively inhibited r3β-HSD1 with IC50 value of 40.11 μM. The compounds acted as mixed/noncompetitive inhibitors, targeting the NAD+ binding pocket. Inhibitory potency correlated with compound hydrophobicity, heavy atom count, and molecular weight. A 3D-QSAR pharmacophore model achieved high predictive accuracy (R2 = 0.98) for h3β-HSD2 inhibition. These biocides suppressed progesterone production in human KGN granulosa tumor cells. The binding free energies were ranged from -6.52 to -7.19 kcal/mol for h3β-HSD2 and -6.0 to -7.04 kcal/mol for r3β-HSD1. The results underscore the endocrine-disrupting capabilities of isothiazolinones via inhibition of critical steroidogenic enzymes, offering insights into their structure-activity relationships and potential side effects.

Endocrine-disrupting chemicals as prostate carcinogens

Endocrine-disrupting chemicals (EDCs) are natural or synthetic compounds that are ubiquitous in the environment and in daily-usage products and interfere with the normal function of the endocrine system leading to adverse health effects in humans. Exposure to these chemicals might elevate the risk of metabolic disorders, developmental and reproductive defects, and endocrine-related cancers. Prostate cancer is the most common hormone-dependent cancer in men, and the fifth leading cause of cancer-related mortality, partly owing to a lack of knowledge about the mechanisms that lead to aggressive castration-resistant forms. In addition to the dependence of early-stage prostate cancer on androgen actions, the prostate is a target of oestrogenic regulation. This hormone dependence, along with the fact that exogenous influences are major risk factors for prostate cancer, make the prostate a likely target of harmful actions from EDCs. Various sources of EDCs and their different modes of action might explain their role in prostate carcinogenesis.

Prenatal Exposure to Synthetic Phenols Assessed in Multiple Urine Samples and Dysregulation of Steroid Hormone Homeostasis in Two European Cohorts

BACKGROUND

Some synthetic phenols alter hormonal pathways involved in successful pregnancy and fetal development. Despite high within-subject temporal variability of phenols, previous studies mostly utilized spot urine samples to assess pregnancy exposure. Herein, we investigated associations between pregnancy exposure to eight phenols assessed in multiple pooled urine samples and steroid hormones assessed in maternal hair reflecting cumulative hormone levels over the previous weeks to months.

METHODS

We assessed phenol-hormone associations in 928 pregnant women from two pooled cohorts recruited in Spain [Barcelona Life Study Cohort (BiSC), 2018-2021] and France [Assessment of Air Pollution exposure during Pregnancy and Effect on Health (SEPAGES), 2014-2017] using pools of up to 21 samples each, collected in early pregnancy (median gestational age: 18.0 wk), as well as hair collected in late pregnancy (BiSC) or at birth (SEPAGES). We measured two bisphenols, four parabens, benzophenone-3, and triclosan along with metabolites of three adrenal (∑ cortisol , ∑ cortisone , and 11-dehydrocorticosterone) and two reproductive (progesterone and testosterone) hormones. We ran adjusted linear regressions for each exposure biomarker-outcome pair and Bayesian kernel machine regression for phenols mixture.

RESULTS

Bisphenol S was associated with higher cortisol and 11-dehydrocorticosterone concentrations. Propylparaben was associated with lower levels of cortisol, cortisone, and 11-dehydrocorticosterone, while methylparaben was linked to a reduction in cortisol levels. Interestingly, associations identified for parabens were stronger for women carrying female fetuses. No associations for phenol mixture were detected.

CONCLUSIONS

Our study suggests that pregnancy exposure to bisphenol S and some parabens (propyl- and methylparaben) may affect production of maternal corticosteroid hormones that are important for a successful pregnancy and fetal development. https://doi.org/10.1289/EHP15117.

Research status of anti-obesogenic functional foods: mechanism of endocrine-disrupting chemicals and glucocorticoid receptor pathway

Obesity due to excessive fat accumulation, affects health and quality of life and increases the risk of diseases such as type 2 diabetes and cardiovascular conditions. Traditional causes, such as calorie excess and sedentary behavior, do not fully explain the obesity epidemic, leading to the hypothesis that endocrine-disrupting chemicals or obesogens contribute to obesity. The obesogenic mechanisms of representative obesogenic substances, such as bisphenols, have been discussed, mainly focusing on their interactions with estrogen receptors. Based on several studies showing that obesogens induce obesity by mimicking glucocorticoids, this review focused on the role of the glucocorticoid receptor pathway. In addition, the anti-obesogenic bioactive substances that have been studied to this date along with their inhibitory mechanisms were discussed.

Prenatal exposure to synthetic chemicals in relation to HPA axis activity: A systematic review of the epidemiological literature

BACKGROUND

Pregnant people are widely exposed to numerous synthetic chemicals with known endocrine-disrupting properties (e.g., phthalates, phenols, per- and poly-fluoroalkyl substances (PFAS)). To date, most epidemiological research on how endocrine-disrupting chemicals (EDCs) disrupt hormone pathways has focused on estrogens, androgens, and thyroid hormones. Far less research has examined the impact of EDCs on the hypothalamic-pituitary-adrenal (HPA) axis, despite its central role in the physiologic stress response and metabolic function.

OBJECTIVE

To systematically review the epidemiological literature on prenatal synthetic EDC exposures in relation to HPA axis hormones (e.g., corticotropin-releasing hormone, adrenocorticotropic hormone, cortisol, cortisone) in pregnant people and their offspring.

METHODS

A literature search of PubMed, Scopus, and Embase was conducted. Primary research studies were selected for inclusion by two independent reviewers and risk of bias was assessed using the Office of Health Assessment and Translation guidelines established by the National Toxicology Program with customization for the specific research topic. Data were extracted from each study and included in a qualitative synthesis.

RESULTS

22 published studies met the inclusion criteria. Phthalates were the most prevalent EDC studied, followed by PFAS, phenols, and parabens, with fewer studies considering other synthetic chemicals. Offspring glucocorticoids were the most commonly considered outcome, followed by maternal glucocorticoids and placental corticotropin-releasing hormone. There was considerable heterogeneity in methods across studies, particularly in HPA axis outcome measures and matrices, making cross-study comparisons challenging. Numerous studies suggested disruption of HPA axis hormones and sex differences in association, but results varied considerably across studies and EDC classes.

CONCLUSIONS

The limited literature to date suggests the HPA axis may be vulnerable to disruption by synthetic EDCs. Carefully designed studies that prioritize biospecimen collection specific to HPA axis hormones are needed along with greater standardization of biospecimen collection and analysis protocols to facilitate cross-study comparisons and interpretation.

Human and rat gonadal 3β-hydroxysteroid dehydrogenases are suppressed by dithiocarbamate fungicides via interacting with cysteine residues

Dithiocarbamates have been widely used in various industrial applications, such as insecticides (ferbam) or drug (disulfiram). This study explored the inhibitory effects of dithiocarbamates on human and rat gonadal 3β-hydroxysteroid dehydrogenases (3β-HSD) and investigated the structure-activity relationship and mechanistic insights. The inhibitory activity of six dithiocarbamates and thiourea on the conversion of pregnenolone to progesterone was evaluated using human KGN cell and rat testicular microsomes, with subsequent progesterone measurement using HPLC-MS/MS. The study found that among the tested compounds disulfiram, ferbam, and thiram exhibited significant inhibitory activity against human 3β-HSD2 and rat 3β-HSD1, with ferbam demonstrating the highest potency. The mode of action for these compounds was characterized, showing mixed inhibition for human 3β-HSD2 and mixed/noncompetitive inhibition for rat 3β-HSD1. Additionally, it was observed that dithiothreitol dose-dependently reversed the inhibitory effects of dithiocarbamates on both human and rat gonadal 3β-HSD enzymes. The study also delved into the penetration of these dithiocarbamates through the human KGN cell membrane and their impact on progesterone production, highlighting their potency in inhibiting human 3β-HSD2. Furthermore, bivariate correlation analysis revealed a positive correlation of LogP (lipophilicity) with IC50 values for both enzymes. Docking analysis indicated that dithiocarbamates bind to NAD+ and steroid-binding sites, with some interactions with cysteine residues. In conclusion, this study provides valuable insights into the structure-activity relationship and mechanistic aspects of dithiocarbamates as inhibitors of human and rat gonadal 3β-HSDs, suggesting that these compounds likely exert their inhibitory effects through binding to cysteine residues.

Glucocorticoid hormones in relation to environmental exposure to bisphenols and multiclass pesticides among middle aged-women: Results from hair analysis

Bisphenols and pesticides have been shown to alter circulating glucocorticoids levels in animals, but there is limited human data. Moreover, measurements from biological fluids may not be able to reflect long-term status of non-persistent pollutants and glucocorticoids due to the high variability in their levels. Using hair analysis, we examined the associations between glucocorticoid hormones and environmental exposure to multi-class organic pollutants among a healthy female population aged 25-45 years old. Concentrations of four glucocorticoids, four polychlorinated biphenyl congeners (PCBs), seven polybrominated diphenyl ether congeners (PBDEs), two bisphenols and 140 pesticides and their metabolites were measured in hair samples collected from 196 Chinese women living in urban areas. Due to the low detection frequency of some pollutants, associations were explored only on 54 pollutants, i.e. PCB 180, bisphenol A, bisphenol S and 51 pesticides and their metabolites. Using stability-based Lasso regression, there were associations of cortisol, tetrahydrocortisol, cortisone, and tetrahydrocortisone with 14, 10, 13 and 17 biomarkers of exposure to pollutants, respectively, with bisphenol S, p,p'-dichlorodiphenyldichloroethylene, diethyl phosphate, 3,5,6-trichloro-2-pyridinol, thiamethoxam, imidacloprid, fipronil, tebuconazole, trifluralin, pyraclostrobin and 1-(3,4-dichlorophenyl)-3-methylurea being associated with at least three of the four hormones. There were also associations between cortisone/cortisol molar ratio and pollutants, namely dimethyl phosphate, 3-methyl-4-nitrophenol, carbofuran, λ-cyhalothrin, permethrin, fipronil, flusilazole, prometryn and fenuron. Some of these relationships were confirmed by single-pollutant linear regression analyses. Overall, our results suggest that background level of exposure to bisphenols and currently used pesticides may interfere with the glucocorticoid homeostasis in healthy women.

Halogenated bisphenol A derivatives potently inhibit human and rat 11β-hydroxysteroid dehydrogenase 1: Structure-activity relationship and molecular docking

Chlorinated bisphenol A (BPA) derivatives are formed during chlorination process of drinking water, whereas bisphenol S (BPS) and brominated BPA and BPS (TBBPA and TBBPS) were synthesized for many industrial uses such as fire retardants. However, the effect of halogenated BPA and BPS derivatives on glucocorticoid metabolizing enzyme 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) remains unclear. The inhibitory effects of 6 BPA derivatives in the inhibition of human and rat 11β-HSD1 were investigated. The potencies for inhibition on human 11β-HSD1 were TBBPA (IC50, 3.87 μM) = monochloro BPA (MCBPA, 4.08 μM) = trichloro BPA (TrCBPA, 4.41 μM) > tetrachloro BPA (TCBPA, 9.75 μM) > TBBPS (>100 μM) = BPS (>100 μM), and those for rat 11β-HSD1 were TrCBPA (IC50, 2.76 μM) = MCBPA (3.75 μM) > TBBPA (39.58 μM) > TCBPA = TBBPS = BPS. All these BPA derivatives are mixed/competitive inhibitors of both human and rat enzymes. Molecular docking studies predict that MCBPA, TrCBPA, TCBPA, and TBBPA all bind to the active site of human 11β-HSD1, forming hydrogen bonds with catalytic residue Ser170 except TCBPA. Regression of the lowest binding energy with IC50 values revealed a significant inverse linear regression. In conclusion, halogenated BPA derivatives are mostly potent inhibitors of human and rat 11β-HSD1, and there is structure-dependent inhibition.

Structure-activity relationship and mechanistic study of organotins as inhibitors of human, pig, and rat gonadal 3β-hydroxysteroid dehydrogenases

Organotins have been widely used in various industrial applications. This study investigated the structure-activity relationship as inhibitors of human, pig, and rat gonadal 3β-hydroxysteroid dehydrogenases (3β-HSD). Human KGN cell, pig, and rat testis microsomes were utilized to assess the inhibitory effects of 18 organotins on the conversion of pregnenolone to progesterone. Among them, diphenyltin, triethyltin, and triphenyltin exhibited significant inhibitory activity against human 3β-HSD2 with IC50 values of 114.79, 106.98, and 5.40 μM, respectively. For pig 3β-HSD, dipropyltin, diphenyltin, triethyltin, tributyltin, and triphenyltin demonstrated inhibitory effects with IC50 values of 172.00, 100.19, 87.00, 5.75, and 1.65 μM, respectively. Similarly, for rat 3β-HSD1, dipropyltin, diphenyltin, triethyltin, tributyltin, and triphenyltin displayed inhibitory activity with IC50 values of 81.35, 43.56, 55.55, 4.09, and 0.035 μM, respectively. They were mixed inhibitors of pig and rat 3β-HSD, while triphenyltin was identified as a competitive inhibitor of human 3β-HSD2. The mechanism underlying the inhibition of organotins on 3β-HSD was explored, revealing that they may disrupt the enzyme activity by binding to cysteine residues in the catalytic sites. This proposition was supported by the observation that the addition of dithiothreitol reversed the inhibition caused by all organotins except for triethyltin, which was partially reversed. In conclusion, this study provides valuable insights into the structure-activity relationship of organotins as inhibitors of human, pig, and rat gonadal 3β-HSD. The mechanistic investigation suggests that these compounds likely exert their inhibitory effects through binding to cysteine residues in the catalytic sites.

Carbon-chain length determines the binding affinity and inhibitory strength of per- and polyfluoroalkyl substances on human and rat steroid 5α-reductase 1 activity

Per- and polyfluoroalkyl substances (PFAS) are widely used synthetic chemicals that persist in the environment and bioaccumulate in animals and humans. There is growing evidence that PFAS exposure adversely impacts neurodevelopment and neurological health. Steroid 5α-reductase 1 (SRD5A1) plays a key role in neurosteroidogenesis by catalyzing the conversion of testosterone or pregnenolone to neuroactive steroids, which influence neural development, cognition, mood, and behavior. This study investigated the inhibitory strength and binding interactions of 18 PFAS on human and rat SRD5A1 activity using enzyme assays, molecular docking, and structure-activity relationship analysis. Results revealed that C9-C14 PFAS carboxylic acid at 100 μM significantly inhibited human SRD5A1, with IC50 values ranged from 10.99 μM (C11) to 105.01 μM (C14), and only one PFAS sulfonic acid (C8S) significantly inhibited human SRD5A1 activity, with IC50 value of 8.15 μM. For rat SRD5A1, C9-C14 PFAS inhibited rat SRD5A1, showing the similar trend, depending on carbon number of the carbon chain. PFAS inhibit human and rat SRD5A1 in a carbon chain length-dependent manner, with optimal inhibition around C11. Kinetic studies indicated PFAS acted through mixed inhibition. Molecular docking revealed PFAS bind to the domain between NADPH and testosterone binding site of both SRD5A1 enzymes. Inhibitory potency correlated with physicochemical properties like carbon number of the carbon chain. These findings suggest PFAS may disrupt neurosteroid synthesis and provide insight into structure-based inhibition of SRD5A1.

Chalcones from plants cause toxicity by inhibiting human and rat 11β-hydroxysteroid dehydrogenase 2: 3D-quantitative structure-activity relationship (3D-QSAR) and in silico docking analysis

Chalcones from licorice and its related plants have many pharmacological effects. However, the effects of chalcones on the activity of human and rat 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2), and associated side effects remain unclear. The inhibition of 11 chalcones on human and rat 11β-HSD2 were evaluated in microsomes and a 3D-quantitative structure-activity relationship (3D-QSAR) was analyzed. Screening revealed that bavachalcone, echinatin, isobavachalcone, isobavachromene, isoliquiritigenin, licochalcone A, and licochalcone B significantly inhibited human 11β-HSD2 with IC50 values ranging from 15.62 (licochalcone A) to 38.33 (echinatin) μM. Screening showed that the above chemicals and 4-hydroxychalcone significantly inhibited rat 11β-HSD2 with IC50 values ranging from 6.82 (isobavachalcone) to 72.26 (4-hydroxychalcone) μM. These chalcones acted as noncompetitive/mixed inhibitors for both enzymes. Comparative analysis revealed that inhibition of 11β-HSD2 depended on the species. Most chemicals bind to the NAD+ binding site or both the NAD+ and substrate binding sites. Bivariate correlation analysis showed that lipophilicity and molecular weight determine inhibitory strength. Through our 3D-QSAR models, we identified that the hydrophobic region, hydrophobic aliphatic groups, and hydrogen bond acceptors are pivotal factors in inhibiting 11β-HSD2. In conclusion, many chalcones inhibit human and rat 11β-HSD2, possibly causing side effects and there is structure-dependent and species-dependent inhibition on 11β-HSD2.

Comparison of structure-activity relationship for bisphenol analogs in the inhibition of gonadal 3β-hydroxysteroid dehydrogenases among human, rat, and mouse

Bisphenol A (BPA) is a widely used plastic material and its potential endocrine disrupting effect has restricted its use and increasing use of BPA alternatives has raised health concerns. However, the effect of bisphenol alternatives on steroidogenesis remains unclear. The objective of this study was to compare inhibitory potencies of 10 BPA alternatives in the inhibition of gonadal 3β-hydroxysteroid dehydrogenase (3β-HSD) in three species (human, rat and mouse). The inhibitory potency for human 3β-HSD2, rat 3β-HSD1, and mouse 3β-HSD6 ranged from bisphenol FL (IC50, 3.32 μM for human, 5.19 μM for rat, and 3.26 μM for mouse) to bisphenol E, F, and thiodiphenol (ineffective at 100 μM). Most BPA alternatives were mixed inhibitors of gonadal 3β-HSD and they dose-dependently inhibited progesterone formation in KGN cells. Molecular docking analysis showed that all BPA analogs bind to steroid and NAD+ active sites. Lipophilicity of BPA alternatives was inversely correlated with IC50 values. In conclusion, BPA alternatives mostly can inhibit gonadal 3β-HSDs and lipophilicity determines their inhibitory strength.

Bisphenol a alternatives suppress human and rat aromatase activity: QSAR structure-activity relationship and in silico docking analysis

The use of alternative substances to replace bisphenol A (BPA) has been encouraged. The objective of this study was to evaluate the effects of BPA and 9 BPA alternatives on human and rat aromatase (CYP19A1) in human and rat placental microsomes. The results revealed that bisphenol A, AP, B, C, E, F, FL, S, and Z, and 4,4'-thiodiphenol (TDP) inhibited human CYP19A1 and bisphenol A, AP, B, C, FL, Z, and TDP inhibited rat CYP19A1. The IC50 values of human CYP19A1 ranged from 3.3 to 172.63 μM and those of rat CYP19A1 ranged from 2.20 to over 100 μM. BPA alternatives were mixed/competitive inhibitors and inhibited estradiol production in BeWo placental cells. Molecular docking analysis showed that BPA alternatives bind to the domain between heme and steroid and form a hydrogen bond with catalytic residue Met374. Pharmacophore analysis showed that there were one hydrogen bond donor, one hydrophobic region, and one ring aromatic hydrophobic region. Bivariate correlation analysis showed that molecular weight, alkyl atom weight, and LogP of BPA alternatives were inversely correlated with their IC50 values. In conclusion, BPA alternatives can inhibit human and rat CYP19A1 and the lipophilicity and the substituted alkyl size determines their inhibitory strength.

Limonin ameliorates cisplatin-induced acute liver injury by inhibiting 11β-hydroxysteroid dehydrogenase type 1

BACKGROUND

Acute liver injury (ALI) is a common side effect of cisplatin treatment in the clinic and can lead to liver failure if not treated promptly. Previous studies have revealed that Limonin, a critical bioactive substance in citrus fruits, can protect multiple organs from various medical conditions. However, whether Limonin could ameliorate cisplatin-induced ALI remains unclear.

METHODS

In vivo and in vitro models were induced by cisplatin in the present study. Non-targeted metabolomics was employed to analyze the metabolic changes in the liver after ALI. In addition, molecular docking was utilized to predict the potential targets of Limonin.

RESULTS

Limonin attenuated hepatic histopathological injury by reducing hepatocyte apoptosis, lipid peroxidation, and inflammation in cisplatin-challenged mice. Employing metabolomics, we revealed that Limonin mediated the balance of various disturbed metabolic pathways in the liver after cisplatin-induced ALI. Integrating public data mining, molecular docking studies, and in vitro experiments demonstrated that Limonin suppressed the expression and activity of its direct target, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), in the liver, thus reducing the production of corticosterone (CORT), a key metabolite promoted hepatocyte apoptosis.

CONCLUSIONS

Limonin improves the liver metabolic microenvironment by inhibiting 11β-HSD1 to protect against cisplatin-induced ALI.

Distinct inhibitory strength of bisphenol A analogues on human and rat 11β-hydroxysteroid dehydrogenase 1: 3D quantitative structure-activity relationship and in silico molecular docking analysis

Bisphenol A (BPA) analogues are developed to replace BPA usage. However, their effects on 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) are largely unknown. The inhibitory effects of BPA and 10 BPA analogues with the substituents on the bridge moiety on human and rat 11β-HSD1 were explored in human and rat liver microsomes. The strength of inhibiting human 11β-HSD1 was bisphenol FL (IC50, 3.87 μM) > bisphenol Z (6.86 μM) > bisphenol AF (9.42 μM) > bisphenol C (16.14 μM) > bisphenol AP (32.14 μM) = bisphenol B (32.34 μM) > 4,4'-thiodiphenol (67.35 μM) > BPA (297.35 μM) > other BPA analogues (ineffective at 100 μM). The strength of inhibiting rat 11β-HSD1 was bisphenol Z (IC50, 14.44 μM) > 4,4'-thiodiphenol (19.01 μM) > bisphenol B (20.13 μM) > bisphenol F (22.10 μM) > bisphenol E (33.04 μM) > bisphenol AF (49.67 μM) > bisphenol C > (56.97 μM) > bisphenol AP (62.71 μM) >bisphenol FL (96.31 μM) > other BPA analogues (ineffective at 100 μM). Bisphenol A, AF, AP, B, C, F, FL, Z, and 4,4'-thiodiphenol bind to the active sites of human and rat 11β-HSD1. Regression of LogP and molecular weight with IC50 values revealed distinct inhibitory pattern (negative correlation for human 11β-HSD1 vs. positive correlation for rat enzyme). Regression of the lowest binding energy with IC50 values revealed a significant positive regression. 3D QSAR pharmacophore analysis showed one hydrogen bond acceptor and two hydrogen bond donors for human 11β-HSD1. In conclusion, most BPA analogues are more potent inhibitors of human and rat 11β-HSD1 enzymes and there is structure-dependent and species-dependent inhibition.

Carbon chain length of perfluoroalkylated carboxylic acids determines inhibitory strength on gonadal 3β-hydroxysteroid dehydrogenases in humans, rats, and mice

Perfluoroalkylated carboxylic acids (PFCAs) are a subclass of man-made chemicals that have been widely used in industrial production and consumer products. As a result, PFCAs have been found to accumulate in the environment and bioaccumulate in organisms, leading to potential health and environmental impacts. This study investigated the inhibition of 11 PFCAs on gonadal 3β-hydroxysteroid dehydrogenases in humans, rats, and mice. We observed a V-shaped inhibition pattern against human granulosa (KGN) cell 3β-HSD2 starting from C9 (half-maximal inhibitory concentration, IC50, 100.8 μM) to C11 (8.92 μM), with a V-shaped turn. The same V-shaped inhibition pattern was also observed for PFCAs against rat testicular 3β-HSD1 from C9 (IC50, 50.43 μM) to C11 (6.60 μM). Mouse gonadal 3β-HSD6 was insensitive to the inhibition of PFCAs, with an IC50 of 50.43 μM for C11. All of these PFCAs were mixed inhibitors of gonadal 3β-HSDs. Docking analysis showed that PFCAs bind to the nicotinamide adenine dinucleotide (NAD+)/steroid binding sites of these enzymes and bivariate correlation analysis showed that molecular length determines the inhibitory pattern of PFCAs on these enzymes. In conclusion, the carbon chain length determines the inhibitory strength of PFCAs on human, rat, and mouse gonadal 3β-HSDs, and the inhibitory strength of PFCAs against human and rat 3β-HSD enzymes shows V-shaped turn.

Benzene ring bisphenol A substitutes potently inhibit human, rat, and mouse gonadal 3β-hydroxysteroid dehydrogenases: Structure-activity relationship and in silico docking analysis

Bisphenol A (BPA) is a chemical used in the production of certain plastics and resins. Recent research has found that BPA can inhibit the activity of 3β-hydroxysteroid dehydrogenase/Δ5,4-isomerases (3β-HSDs). Whether benzene ring BPA substitutes can inhibit human, rat, and mouse gonadal 3β-HSDs, the structure-activity relationship and the underlying mechanism remain unclear. In this study, we compared 6 benzene ring BPA substitutes to BPA in the inhibition of human, rat, and mouse gonadal 3β-HSDs and conducted structure-activity relationship and in silico docking analysis. The inhibitory activity (IC50) of human 3β-HSD2 in KGN cells ranged from about 0.02 μM for bisphenol H to 8.75 μM for BPA, that of rat 3β-HSD1 in testicular microsomes ranged from 0.099 μM for bisphenol H to 31.32 μM for BPA, and that of mouse 3β-HSD6 ranged from 0.021 μM for BPH to ineffectiveness for 100 μM BPA. These compounds acted as mixed inhibitors with LogP inversely correlated with IC50 and ΔG positively correlated with IC50 value. Docking analysis showed that these compounds bind to the steroid active site of the 3β-HSD enzymes. In conclusion, some benzene ring BPA substitutes potently inhibit gonadal 3β-HSD in various species, and lipophilicity and binding affinity determine their inhibitory strength.

Azole fungicides inhibit human and rat gonadal 3β-hydroxysteroid dehydrogenases: Structure-activity relationship and in silico docking analysis

Azole fungicides are widely used in the agricultural industry to control fungal infections in crops. However, recent studies have shown that some azole fungicides inhibit the activity of 3β-hydroxysteroid dehydrogenases (3β-HSDs) in the gonads. Out of the 16 azole fungicides tested, 8 were found to inhibit human KGN cell 3β-HSD2 with IC50 values of less than 100 μM. The strongest inhibitor was difenoconazole, with an IC50 value of 1.88 μM. In contrast, only 3 of the azole fungicides inhibited rat testicular 3β-HSD1, which was less sensitive to inhibition. Azole fungicides potently inhibited progesterone secretion by KGN cells under basal and forskolin stimulated conditions at ≥ 5 μM. The inhibitory strength of azole fungicides was determined by their lipophilicity (LogP), molecular weight, pKa, and binding energy. A pharmacophore analysis revealed that the hydrogen bond acceptor-lipid group was a critical feature required for inhibition. Overall, these findings suggest that the use of azole fungicides have unintended consequences on reproductive health due to their inhibition of gonadal 3β-HSDs. Key words: Azole fungicides; steroid hormones; 3β-hydroxysteroid dehydrogenase; docking analysis; lipophilicity.

Halogenated bisphenol A derivatives potently inhibit human, rat, and mouse gonadal 3β-hydroxysteroid dehydrogenases: Structure-activity relationship and in silico molecular docking analysis

Bisphenol A (BPA) is a widely used plastic material, and halogenated BPA derivatives are formed either by synthesis or environmental processes. However, the effect of halogenated bisphenols on steroidogenesis remains unclear. The aim of this study was to compare inhibition of 6 BPA derivatives on gonadal 3β-hydroxysteroid dehydrogenases (3β-HSDs) in three species (human, rat, and mouse). The inhibition on human 3β-HSD2 was tetrabromo BPA (TBBPA, IC50, 1.01 μM)>trichloro BPA (TrCBPA, 3.95 μM)>tetrachloro BPA (TCBPA, 4.14 μM)>monochloro BPA (MCBPA, 4.74 μM)>others with TrCBPA of competitive, TBBPA of noncompetitive and MCBPA/TCBPA of mixed inhibition. The inhibition on rat 3β-HSD1 was TCBPA (1.68 μM)>TrCBPA (1.72 μM)>MCBPA (2.80 μM)>BPA>others with mixed inhibition. The inhibition on mouse 3β-HSD6 was TrCBPA (1.59 μM) >MCBPA (3.36 μM)>TCBPA (3.72 μM)>others with mixed inhibition. Molecular docking analysis showed that TBBPA, TrCBPA, and TCBPA bind to steroid active sites, contacting with catalytic residue Tyr154 of human 3β-HSD2. MCBPA, TrCBPA, and TCBPA bind to steroid active site of rat 3β-HSD1. MCBPA and TrCBPA bind to active site of mouse 3β-HSD6. Regression of lowest binding energy values with Ki values revealed a significant negative linear regression (P < 0.05). In conclusion, halogenated BPA derivatives are more potent inhibitors of three 3β-HSDs than BPA and there is structure-dependent inhibition. SYNOPSIS: Chlorinated bisphenol derivatives after water chlorination process and other halogenated bisphenols effectively inhibit human and rat 3β-HSD activity, thereby leading to steroid hormone deficiency.

Bisphenol A Analogues Inhibit Human and Rat 11β-Hydroxysteroid Dehydrogenase 1 Depending on Its Lipophilicity

Bisphenol A (BPA) analogues substituted on the benzene ring are widely used in a variety of industrial and consumer materials. However, their effects on the glucocorticoid-metabolizing enzyme 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) remain unclear. The inhibitory effects of 6 BPA analogues on the inhibition of human and rat 11β-HSD1 were investigated. The potencies of inhibition on human 11β-HSD1 were bisphenol H (IC₅₀, 0.75 µM) > bisphenol G (IC₅₀, 5.06 µM) > diallyl bisphenol A (IC₅₀, 13.36 µM) > dimethyl bisphenol A (IC₅₀, 30.18 µM) > bisphenol A dimethyl ether (IC₅₀, 33.08 µM) > tetramethyl bisphenol A (>100 µM). The inhibitory strength of these chemicals on rat 11β-HSD1 was much weaker than that on the human enzyme, ranging from 74.22 to 205.7 µM. All BPA analogues are mixed/competitive inhibitors of both human and rat enzymes. Molecular docking studies predict that bisphenol H and bisphenol G both bind to the active site of human 11β-HSD1, forming a hydrogen bond with catalytic residue Ser170. The bivariate correlation of IC₅₀ values with LogP (lipophilicity), molecular weight, heavy atoms, and molecular volume revealed a significant inverse regression and the correlation of IC₅₀ values with ΔG (low binding energy) revealed a positive regression. In conclusion, the lipophilicity, molecular weight, heavy atoms, molecular volume, and binding affinity of a BPA analogue determine the inhibitory strength of human and rat 11β-HSD isoforms.

Direct inhibition of bisphenols on human and rat 11β-hydroxysteroid dehydrogenase 2: Structure-activity relationship and docking analysis

Bisphenols (BPs) as endocrine-disrupting compounds have drawn attention to their health hazards. Whether a BP interferes with glucocorticoid metabolism remains unclear. 11β-Hydroxysteroid dehydrogenase 2 (11β-HSD2) is a key glucocorticoid-metabolizing enzyme that controls fetal glucocorticoid levels across the placental barrier and mineralocorticoid receptor specificity in the kidney. In this study, 11 BPs were tested to inhibit human placental and rat renal 11β-HSD2 and were analyzed for inhibitory potency, mode action, and docking parameters. BPs had inhibitory potency against human 11β-HSD2: BPFL>BPAP>BPZ>BPB>BPC>BPAF>BPA>TDP and the IC₁₀ values were 0.21, 0.55, 1.04, 2.04, 2.43, 2.57, 14.43, and 22.18 μM, respectively. All BPs are mixed inhibitors except BPAP, which is a competitive inhibitor for human 11β-HSD2. Some BPs also inhibited rat renal 11β-HSD2, with BPB (IC₅₀, 27.74 ± 0.95) > BPZ (42.14 ± 0.59) > BPAF (54.87 ± 1.73) > BPA (77.32 ± 1.20) > other BPs (about 100 μM). Docking analysis showed that all BPs bound to the steroid-binding site, interacting with the catalytic residue Tyr232 of both enzymes and the most potent human 11β-HSD2 inhibitor BPFL acts possibly due to its large fluorene ring that has hydrophobic interaction with residues Glu172 and Val270 and π-stacking interaction with catalytic residue Tyr232. The increase in the size of substituted alkanes and halogenated groups in the methane moiety of the bridge of BPs increases its inhibitory potency. Regressions of the lowest binding energy with inhibition constant indicated that there was an inverse regression. These results indicated that BPs significantly inhibited human and rat 11β-HSD2 activity and that there were species-dependent differences.

Halogen atoms determine the inhibitory potency of halogenated bisphenol A derivatives on human and rat placental 11β-hydroxysteroid dehydrogenase 2

Some halogenated bisphenol A (BPA) derivatives (tetrabromobisphenol A, TBBPA, and tetrachlorobisphenol A, TCBPA) are produced in a high volume and exist in PM_2.5 after waste burning. 11β-Hydroxysteroid dehydrogenase 2 (11β-HSD2) is a critical enzyme for placental function. However, whether halogenated bisphenols inhibit 11β-HSD2 and the mode of action remains unclear. The objective of this study was to investigate BPA derivatives on human and rat placental 11β-HSD2. The inhibitory strength on human 11β-HSD2 was TBBPA (IC₅₀, 0.665 μM)>TCBPA (2.22 μM)>trichloro BPA (TrCBPA, 19.87 μM)>tetrabromobisphenol S (TBBPS, 36.76 μM)>monochloro BPA (MCBPA, 104.0 μM)>BPA (144.9 μM)>bisphenol S. All chemicals are mixed and competitive inhibitors. Rat 11β-HSD2 was less sensitive to BPA derivatives, with TBBPA (IC₅₀, 96.63 μM)>TCBPA (99.69 μM)>TrCBPA (104.1 μM)>BPA (117.1 μM)>others. Docking analysis showed that BPA derivatives bind steroid active sites. Structure-activity relationship revealed that halogen atoms and LogP were inversely correlated with inhibitory strength on human 11β-HSD2, while LogS and polar desolvation energy were positively correlated with the inhibitory strength. In conclusion, halogenated BPA derivatives are mostly potent inhibitors on human 11β-HSD2 and there is structure-dependent inhibition.

Endocrine disrupting chemicals: effects on pituitary, thyroid and adrenal glands

BACKGROUND

In recent years, scientific research has increasingly focused on Endocrine Disrupting Chemicals (EDCs) and demonstrated their relevant role in the functional impairment of endocrine glands. This induced regulatory authorities to ban some of these compounds and to carefully investigate others in order to prevent EDCs-related conditions. As a result, we witnessed a growing awareness and interest on this topic.

AIMS

This paper aims to summarize current evidence regarding the detrimental effects of EDCs on pivotal endocrine glands like pituitary, thyroid and adrenal ones. Particularly, we directed our attention on the known and the hypothesized mechanisms of endocrine dysfunction brought by EDCs. We also gave a glimpse on recent findings from pioneering studies that could in the future shed a light on the pathophysiology of well-known, but poorly understood, endocrine diseases like hormone-producing adenomas.

CONCLUSIONS

Although intriguing, studies on endocrine dysfunctions brought by EDCs are challenging, in particular when investigating long-term effects of EDCs on humans. However, undoubtedly, it represents a new intriguing field of science research.

Investigation of combined effects of propyl paraben and methyl paraben on the hypothalamic-pituitary-adrenal axis in male rats

The aim of this study was to investigate the endocrine-disrupting effects of methyl paraben (MeP) and propyl paraben (PrP) mixture on the hypothalamic-pituitary-adrenal axis (HPA). In this study, six experimental groups were designated. These groups included three control groups (control, corn oil control, and positive control (50 mg/kg/day BPA)) and three dose groups (10, 100, and 500 mg/kg/day MeP+PrP). MeP with PrP were mixed in a 1:1 ratio and administered to the 42-day-old male rats by oral gavage for 30 days. At the end of the experiment, adrenocorticotropic hormone (ACTH), corticosterone and aldosterone hormones were analyzed in serum. Effects of MeP+PrP on the adrenal glands were investigated by immunohistochemical staining of 11ß hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) enzymes involved in the synthesis steps of corticosterone and aldosterone. Also, pituitary and adrenal glands were examined histopathologically. In the histopathological findings, cortical nodule, congestion, and edema were found in the tissues. In the pituitary gland, cytokeratin rings were detected in all MeP+PrP dose groups, supporting the increase of corticosterone and ACTH. Serum corticosterone, aldosterone, and ACTH hormone levels were increased in the 100 mg/kg/day MeP+PrP and BPA groups. Results obtained from immunohistochemical staining showed that increased staining parallelled increased corticosterone and aldosterone hormone levels. In summary, the results showed that exposure to the MeP+PrP mixture caused a significant increase in ACTH and corticosterone. Also, the MeP+PrP mixture caused a significant increase of CYP11B1 and CYP11B2. MeP+PrP exposure disrupts the normal HPA axis.

5-Bis-(2,6-difluoro-benzylidene) Cyclopentanone Acts as a Selective 11β-Hydroxysteroid Dehydrogenase one Inhibitor to Treat Diet-Induced Nonalcoholic Fatty Liver Disease in Mice

Background: 11β-Hydroxysteroid dehydrogenase one is responsible for activating inert glucocorticoid cortisone into biologically active cortisol in humans and may be a novel target for the treatment of nonalcoholic fatty liver disease.

Methods: A series of benzylidene cyclopentanone derivatives were synthesized, and the selective inhibitory effects on rat, mouse and human 11β-hydroxysteroid dehydrogenase one and two were screened. The most potent compound [5-bis-(2,6-difluoro-benzylidene)-cyclopentanone] (WZS08), was used to treat nonalcoholic fatty liver disease in mice fed a high-fat-diet for 100 days.

Results: WZS08 was the most potent inhibitor of rat, mouse, and human 11β-hydroxysteroid dehydrogenase 1, with half maximum inhibitory concentrations of 378.0, 244.1, and 621.1 nM, respectively, and it did not affect 11β-hydroxysteroid dehydrogenase two at 100 μM. When mice were fed WZS08 (1, 2, and 4 mg/kg) for 100 days, WZS08 significantly lowered the serum insulin levels and insulin index at 4 mg/kg. WZS08 significantly reduced the levels of serum triglycerides, cholesterol, low-density lipoprotein, and hepatic fat ratio at low concentration of 1 mg/kg. It down-regulated Plin2 expression and up-regulated Fabp4 expression at low concentration of 1 mg/kg. It significantly improved the morphology of the non-alcoholic fatty liver.

Conclusion: WZS08 selectively inhibits rat, mouse, and human 11β-hydroxysteroid dehydrogenase 1, and can treat non-alcoholic fatty liver disease in a mouse model.

Plastics derived endocrine-disrupting compounds and their effects on early development

Despite the fact that the estrogenic effects of bisphenols were first described 80 years ago, recent data about its potential negative impact on birth outcome parameters raises a strong rationale to investigate further. The adverse health effects of plastics recommend to measure the impacts of endocrine-disrupting compounds (EDCs) such as bisphenols (BPA, BPS, BPF), bis(2-ethylhexyl) phthalate, and dibutyl phthalate (DBP) in human health. Exposure to these compounds in utero may program the diseases of the testis, prostate, kidney and abnormalities in the immune system, and cause tumors, uterine hemorrhage during pregnancy and polycystic ovary. These compounds also control the processes of epigenetic transgenerational inheritance of adult-onset diseases by modulating DNA methylation and epimutations in reproductive cells. The early developmental stage is the most susceptible window for developmental and genomic programming. The critical stages of the events for a normal human birth lie between the many transitions occurring between spermatogenesis, egg fertilization and the fully formed fetus. As the cells begin to grow and differentiate, there are critical balances of hormones, and protein synthesis. Data are emerging on how these plastic-derived compounds affect embryogenesis, placentation and feto-placental development since pregnant women and unborn fetuses are often exposed to these factors during preconception and throughout gestation. Impaired early development that ultimately influences fetal outcomes is at the center of many developmental disorders and contributes an independent risk factor for adult chronic diseases. This review will summarize the current status on the impact of exposure to plastic derived EDCs on the growth, gene expression, epigenetic and angiogenic activities of the early fetal development process and their possible effects on birth outcomes.

Bisphenols and Leydig Cell Development and Function

Bisphenol A (BPA) is a ubiquitous environmental pollutant, mainly from the production and use of plastics and the degradation of wastes related to industrial plastics. Evidence from laboratory animal and human studies supports the view that BPA has an endocrine disrupting effect on Leydig cell development and function. To better understand the adverse effects of BPA, we reviewed its role and mechanism by analyzing rodent data in vivo and in vitro and human epidemiological evidence. BPA has estrogen and anti-androgen effects, thereby destroying the development and function of Leydig cells and causing related reproductive diseases such as testicular dysgenesis syndrome, delayed puberty, and subfertility/infertility. Due to the limitation of BPA production, the increased use of BPA analogs has also attracted attention to these new chemicals. They may share actions and mechanisms similar to or different from BPA.

Glucocorticoid and mineralocorticoid receptors and corticosteroid homeostasis are potential targets for endocrine-disrupting chemicals

Endocrine-disrupting chemicals (EDCs) have received significant concern, since they ubiquitously exist in the environment and are able to induce adverse health effects on human and wildlife. Increasing evidence shows that the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR), members of the steroid receptor subfamily, are potential targets for EDCs. GR and MR mediate the actions of glucocorticoids and mineralocorticoids, respectively, which are two main classes of corticosteroids involved in many physiological processes. The effects of EDCs on the homeostasis of these two classes of corticosteroids have also gained more attention recently. This review summarized the effects of environmental GR/MR ligands on receptor activity, and disruption of corticosteroid homeostasis. More than 130 chemicals classified into 7 main categories were reviewed, including metals, metalloids, pesticides, bisphenol analogues, flame retardants, other industrial chemicals and pharmaceuticals. The mechanisms by which EDCs interfere with GR/MR activity are primarily involved in ligand-receptor binding, nuclear translocation of the receptor complex, DNA-receptor binding, and changes in the expression of endogenous GR/MR genes. Besides directly interfering with receptors, enzyme-catalyzed synthesis and prereceptor regulation pathways of corticosteroids are also important targets for EDCs. The collected evidence suggests that corticosteroids and their receptors should be considered as potential targets for safety assessment of EDCs. The recognition of relevant xenobiotics and their underlying mechanisms of action is still a challenge in this emerging field of research.

Bisphenol A stimulates differentiation of rat stem Leydig cells in vivo and in vitro

Bisphenol A (BPA) is widely used in consumer products and a potential endocrine disruptor linked with sexual precocity. However, its action and underlying mechanisms on male sexual maturation is unclear. In the present study, we used a unique in vivo ethane dimethane sulfonate (EDS)-induced Leydig cell regeneration model that mimics the pubertal development of Leydig cells and an in vitro stem Leydig cell differentiation model to examine the roles of BPA in Leydig cell development in rats. Intratesticular exposure to doses (100 and 1000 pmol/testis) of BPA from post-EDS day 14-28 stimulated Leydig cell developmental regeneration process by increasing serum testosterone level and Leydig cell-specific gene (Lhcgr, Star, Cyp11a1, Hsd3b1, Cyp17a1, Hsd17b3, and Hsd11b1) and their protein expression levels. BPA did not alter serum luteinizing hormone and follicle-stimulating hormone levels as well as the proliferative capacity of Leydig cells in vivo. In vitro study demonstrated that BPA (100 nmol/L) stimulated the differentiation of stem Leydig cells by increasing medium testosterone levels and up-regulating Leydig cell-specific gene (Lhcgr, Cyp11a1, Hsd3b1, Cyp17a1, and Hsd17b3) and their proteins but did not affect their proliferation measured by EdU incorporation. In conclusion, BPA stimulates the differentiation of stem Leydig cells in rat testes, thus possibly causing sexual precocity in the male.

Dehydroepiandrosterone Antagonizes Pain Stress-Induced Suppression of Testosterone Production in Male Rats

Background: Leydig cells secrete the steroid hormone, testosterone, which is essential for male fertility and reproductive health. Stress increases the secretion of glucocorticoid [corticosterone, (CORT) in rats] that decreases circulating testosterone levels in part through a direct action on its receptors in Leydig cells. Intratesticular CORT level is dependent on oxidative inactivation of CORT by 11β-hydroxysteroid dehydrogenase 1 (HSD11B1) in rat Leydig cells. Pain may cause the stress, thus affecting testosterone production in Leydig cells.

Methods: Adult male Sprague–Dawley rats orally received vehicle control or 5 or 10 mg/kg dehydroepiandrosterone (DHEA) 0.5 h before being subjected to pain stimulation for 1, 3, and 6 h. In the present study, we investigated the time-course changes of steroidogenic gene expression levels after acute pain-induced stress in rats and the possible mechanism of DHEA that prevented it. Plasma CORT, luteinizing hormone (LH), and testosterone (T) levels were measured, and Leydig cell gene expression levels were determined. The direct regulation of HSD11B1 catalytic direction by DHEA was detected in purified rat Leydig, liver, and rat Hsd11b1-transfected COS1 cells.

Results: Plasma CORT levels were significantly increased at hour 1, 3, and 6 during the pain stimulation, while plasma T levels were significantly decreased starting at hour 3 and 6. Pain-induced stress also decreased Star, Hsd3b1, and Cyp17a1 expression levels at hour 3. When 5 and 10 mg/kg DHEA were orally administered to rats 0.5 h before starting pain stimulation, DHEA prevented pain-mediated decrease in plasma T levels and the expression of Star, Hsd3b1, and Cyp17a1 without affecting plasma CORT levels. DHEA was found to modulate HSD11B1 activities by increasing its oxidative activity and decreasing its reductive activity, thus decreasing the intracellular CORT levels in Leydig cells.

Conclusion: Stress induced by acute pain can inhibit Leydig cell T production by upregulation of corticosterone. DHEA can prevent the negative effects of excessive corticosterone by modulating HSD11B1 activity.

Recent advances in the study of 11β-Hydroxysteroid dehydrogenase type 2 (11β-HSD2)Inhibitors

11β-Hydroxysteroid dehydrogenase (11β-HSD), which interconverts hormonally active cortisol and inactive cortisone in multiple human tissues, has two distinct isoforms named 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) and 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2). 11β-HSD2 is an NAD⁺-dependent oxidase which lowers cortisol by converting it to cortisone while 11β-HSD1 mainly catalyzes the reduction which converts cortisone into cortisol. Selective inhibition of 11β-HSD2 is generally detrimental to health because the accumulation of cortisol can cause metabolic symptoms such as apparent mineralocorticoid excess (AME), fetal developmental defects and lower testosterone levels in males. There has been some advances on the study of 11β-HSD2 inhibitors and we think it necessary to make a summary of the characteristics and inhibiting properties of latest 11β-HSD2 inhibitors. As another review on 11β-HSD2 inhibitors has been issued on 2011 (see review (Ma et al., 2011)), this mini-review concerns advances during the last 5 years.

Human exposure to endocrine disrupting compounds: Their role in reproductive systems, metabolic syndrome and breast cancer. A review

Endocrine disrupting chemicals (EDCs) are released into the environment from different sources. They are mainly used in packaging industries, pesticides and food constituents. Clinical evidence, experimental models, and epidemiological studies suggest that EDCs have major risks for humans by targeting different organs and systems in the body (e.g. reproductive system, breast tissue, adipose tissue, pancreas, etc.). Due to the ubiquity of human exposure to these compounds the aim of this review is to describe the most recent data on the effects induced by phthalates, bisphenol A and parabens in a critical window of exposure: in utero, during pregnancy, infants, and children. The interactions and mechanisms of toxicity of EDCs in relation to human general health problems, especially those broadening the term of endocrine disruption to 'metabolic disruption', should be deeply investigated. These include endocrine disturbances, with particular reference to reproductive problems and breast, testicular and ovarian cancers, and metabolic diseases such as obesity or diabetes.

Endocrine disruptors and other inhibitors of 11β-hydroxysteroid dehydrogenase 1 and 2: Tissue-specific consequences of enzyme inhibition

Numerous chemicals in the environment have the ability to interact with the endocrine system. These compounds are called endocrine disruptors (EDs). Exposure to EDs represents one of the hypotheses for decreasing fertility, the increased risk of numerous cancers and obesity, metabolic syndrome and type 2 diabetes. There are various mechanisms of ED action, one of which is their interference in the action of 11β-hydroxysteroid dehydrogenase (11βHSD) that maintains a balance between active and inactive glucocorticoids on the intracellular level. This enzyme has two isoforms and is expressed in various tissues. Inhibition of 11βHSD in various tissues can have different consequences. In the case of EDs, the results of exposure are mainly adverse; on the other hand pharmaceutically developed inhibitors of 11βHSD type 1 are evaluated as an option for treating metabolic syndrome, as well as related diseases and depressive disorders. This review focuses on the effects of 11βHSD inhibitors in the testis, colon, adipose tissue, kidney, brain and placenta.

Steroids and endocrine disruptors--History, recent state of art and open questions

This introductory chapter provides an overview of the levels and sites at which endocrine disruptors (EDs) affect steroid actions. In contrast to the special issue of Journal of Steroid Biochemistry and Molecular Biology published three years ago and devoted to EDs as such, this paper focuses on steroids. We tried to point to more recent findings and opened questions. EDs interfere with steroid biosynthesis and metabolism either as inhibitors of relevant enzymes, or at the level of their expression. Particular attention was paid to enzymes metabolizing steroid hormones to biologically active products in target cells, such as aromatase, 5α-reductase and 3β-, 11β- and 17β-hydroxysteroid dehydrogenases. An important target for EDs is also steroid acute regulatory protein (StAR), responsible for steroid precursor trafficking to mitochondria. EDs influence receptor-mediated steroid actions at both genomic and non-genomic levels. The remarkable differences in response to various steroid-receptor ligands led to a more detailed investigation of events following steroid/disruptor binding to the receptors and to the mapping of the signaling cascades and nuclear factors involved. A virtual screening of a large array of EDs with steroid receptors, known as in silico methods (≡computer simulation), is another promising approach for studying quantitative structure activity relationships and docking. New data may be expected on the effect of EDs on steroid hormone binding to selective plasma transport proteins, namely transcortin and sex hormone-binding globulin. Little information is available so far on the effects of EDs on the major hypothalamo-pituitary-adrenal/gonadal axes, of which the kisspeptin/GPR54 system is of particular importance. Kisspeptins act as stimulators for hormone-induced gonadotropin secretion and their expression is regulated by sex steroids via a feed-back mechanism. Kisspeptin is now believed to be one of the key factors triggering puberty in mammals, and various EDs affect its expression and function. Finally, advances in analytics of EDs, especially those persisting in the environment, in various body fluids (plasma, urine, seminal fluid, and follicular fluid) are mentioned. Surprisingly, relatively scarce information is available on the simultaneous determination of EDs and steroids in the same biological material. This article is part of a Special Issue entitled 'Endocrine disruptors & steroids'.

Reprint of "In silico methods in the discovery of endocrine disrupting chemicals"

The prevalence of sex hormone-dependent cancers, reproductive problems, obesity, and cardiovascular complications has risen especially in the Western world. It has been suggested, that the exposure to various endocrine disrupting chemicals (EDCs) contributes to the development and progression of these diseases. EDCs can interfere with various proteins: nuclear steroid hormone receptors, such as estrogen-, androgen-, glucocorticoid- and mineralocorticoid receptors (ER, AR, GR, MR), and enzymes that are involved in steroid hormone synthesis and metabolism, for example hydroxysteroid dehydrogenases (HSDs). Numerous chemicals are known as endocrine disruptors. However, the mechanism of action for most of these EDCs is still unknown. It is exhaustive and time consuming to test in vitro all chemicals - potential EDCs - used in industry, agriculture or as food preservatives against their effects on the endocrine system. Computational methods, such as virtual screening, quantitative structure activity relationships and docking, are already well recognized and used in drug development. The same methods could also aid the research on EDCs. So far, the computational methods in the search of EDCs have been retrospective. There are, however, some prospective studies reporting the use of in silico methods: five studies reporting the identification of previously unknown 17β-HSD3 inhibitors, MR agonists, and ER antagonists/agonists. This review provides an overview of case studies and in silico methods that are used in the search of EDCs. This article is part of a Special Issue entitled 'CSR 2013'.

Gestational bisphenol A exposure and testis development

Virtually all humans are exposed to bisphenol A (BPA). Since BPA can act as a ligand for estrogen receptors, potential hazardous effects of BPA should be evaluated in the context of endogenous estrogenic hormones. Because estrogen is metabolized in the placenta, developing fetuses are normally exposed to very low endogenous estrogen levels. BPA, on the other hand, passes through the placenta and might have distinct adverse consequences during the sensitive stages of fetal development. Testicular gametogenesis and steroidogenesis begin early during fetal development. These processes are sensitive to estrogens and play a role in determining the number of germ stem cells, sperm count, and male hormone levels in adulthood. Although studies have shown a correlation between BPA exposure and perturbed reproduction, a clear consensus has yet to be established as to whether current human gestational BPA exposure results in direct adverse effects on male genital development and reproduction. However, studies in animals and in vitro have provided direct evidence for the ability of BPA exposure to influence male reproductive development. This review discusses the current knowledge of potential effects of BPA exposure on male reproductive health and whether gestational exposure adversely affects testis development.

Ligand-dependent stabilization of androgen receptor in a novel mouse ST38c Sertoli cell line

Mature Sertoli cells (SC) are critical mediators of androgen regulation of spermatogenesis, via the androgen receptor (AR) signaling. Available immortalized SC lines loose AR expression or androgen responsiveness, hampering the study of endogenous AR regulation in SC. We have established and characterized a novel clonal mouse immortalized SC line, ST38c. These cells express some SC specific genes (sox9, wt1, tjp1, clu, abp, inhbb), but not fshr, yet more importantly, maintain substantial expression of endogenous AR as determined by PCR, immunocytochemistry, testosterone binding assays and Western blots. Microarrays allowed identification of some (146) but not all (rhox5, spinlw1), androgen-dependent, SC expressed target genes. Quantitative Real-Time PCR validated regulation of five up-regulated and two down-regulated genes. We show that AR undergoes androgen-dependent transcriptional activation as well as agonist-dependent posttranslational stabilization in ST38c cells. This cell line constitutes a useful experimental tool for future investigations on the molecular and cellular mechanisms of androgen receptor signaling in SC function.

Synthesis of novel curcumin analogues for inhibition of 11β-hydroxysteroid dehydrogenase type 1 with anti-diabetic properties

In the present study, a series of mono-carbonyl analogues of curcumin were designed and synthesized by deleting the reactive beta-diketone moiety, which is responsible for the pharmacokinetic limitation of curcumin. We demonstrated that 4 of 9 curcumin analogues were selective inhibitors of human and rodent 11β-HSD1. The level of this inhibitor was 4-20 times more than that of curcumin. Curcumin analogues weakly inhibited 11β-HSD2, and further analyses revealed that these compounds were highly selective, favoring 11β-HSD1. These 4 curcumin analogues are potential therapeutic agents for type-2 diabetes by targeting 11β-HSD1. The compound 8 displays anti-diabetic properties in diabetic mice induced by streptozocin and high-fat-diet (STZHFD).

Environmental pollutants and hydroxysteroid dehydrogenases

Hydroxysteroid dehydrogenases (HSD) are a group of steroidogenic enzymes that are involved in the steroid biosynthesis and metabolism. Four classes of HSDs, namely, 3β-, 11β-, 17β-, and 20α-HSDs, are discussed. 3β-HSDs catalyze the conversion of pregnenolone, 17α-hydroxypregnenolone, and dehydroepiandrosterone to progesterone, 17α-hydroxyprogesterone, and androstenedione, respectively. 11β-HSDs catalyze the interconversion between active cortisol and inactive cortisone. 17β-HSDs catalyze the interconversion between 17β-hydroxyl steroids and 17-ketoandrogens and estrogens. 20α-HSDs catalyze the conversion of progesterone into 20α-hydroxyprogesterone. Many environmental pollutants directly inhibit one or more enzymes of these HSDs, thus interfering with endogenous active steroid hormone levels. These chemicals include industrial materials (perfluoroalkyl compounds, phthalates, bisphenol A, and benzophenone), pesticides/biocides (methoxychlor, organotins, 1,2-dibromo-3-chloropropane, and prochloraz), and plant constituents (genistein, gossypol, and licorice). This chapter reviews these inhibitors targeting on HSDs.

In silico methods in the discovery of endocrine disrupting chemicals

The prevalence of sex hormone-dependent cancers, reproductive problems, obesity, and cardiovascular complications has risen especially in the Western world. It has been suggested, that the exposure to various endocrine disrupting chemicals (EDCs) contributes to the development and progression of these diseases. EDCs can interfere with various proteins: nuclear steroid hormone receptors, such as estrogen-, androgen-, glucocorticoid- and mineralocorticoid receptors (ER, AR, GR, MR), and enzymes that are involved in steroid hormone synthesis and metabolism, for example hydroxysteroid dehydrogenases (HSDs). Numerous chemicals are known as endocrine disruptors. However, the mechanism of action for most of these EDCs is still unknown. It is exhaustive and time consuming to test in vitro all chemicals - potential EDCs - used in industry, agriculture or as food preservatives against their effects on the endocrine system. Computational methods, such as virtual screening, quantitative structure activity relationships and docking, are already well recognized and used in drug development. The same methods could also aid the research on EDCs. So far, the computational methods in the search of EDCs have been retrospective. There are, however, some prospective studies reporting the use of in silico methods: five studies reporting the identification of previously unknown 17β-HSD3 inhibitors, MR agonists, and ER antagonists/agonists. This review provides an overview of case studies and in silico methods that are used in the search of EDCs. This article is part of a Special Issue entitled 'CSR 2013'.