Intracrine androgen biosynthesis, metabolism and action revisited

Non-Classic Disorder of Adrenal Steroidogenesis and Clinical Dilemmas in 21-Hydroxylase Deficiency Combined with Backdoor Androgen Pathway. Mini-Review and Case Report

Congenital adrenal hyperplasia (CAH) is the most common cause of primary adrenal insufficiency in children and adolescents. It comprises several clinical entities associated with mutations in genes, encoding enzymes involved in cortisol biosynthesis. The mutations lead to considerable (non-classic form) to almost complete (classic form) inhibition of enzymatic activity, reflected by different phenotypes and relevant biochemical alterations. Up to 95% cases of CAH are due to mutations in CYP21A2 gene and subsequent 21α-hydroxylase deficiency, characterized by impaired cortisol synthesis and adrenal androgen excess. In the past two decades an alternative ("backdoor") pathway of androgens' synthesis in which 5α-androstanediol, a precursor of the 5α-dihydrotestosterone, is produced from 17α-hydroxyprogesterone, with intermediate products 3α,5α-17OHP and androsterone, in the sequence and with roundabout of testosterone as an intermediate, was reported in some studies. This pathway is not always considered in the clinical assessment of patients with hyperandrogenism. The article describes the case of a 17-year-old female patient with menstrual disorders and androgenization (persistent acne, advanced hirsutism). Her serum dehydroepiandrosterone sulfate and testosterone were only slightly elevated, along with particularly high values for 5α-dihydrotestosterone. In 24 h urine collection, an increased excretion of 16α-OHDHEA-a dehydroepiandrosterone metabolite-and pregnanetriolone-a 17α-hydroxyprogesterone metabolite-were observed. The investigations that we undertook provided evidence that the girl suffered from non-classic 21α-hydroxylase deficiency with consequent enhancement of the androgen "backdoor" pathway in adrenals, peripheral tissues or both, using adrenal origin precursors. The paper presents diagnostic dilemmas and strategies to differentiate between various reasons for female hyperandrogenism, especially in childhood and adolescence.

Steroids and TRP Channels: A Close Relationship

Transient receptor potential (TRP) channels are remarkable transmembrane protein complexes that are essential for the physiology of the tissues in which they are expressed. They function as non-selective cation channels allowing for the signal transduction of several chemical, physical and thermal stimuli and modifying cell function. These channels play pivotal roles in the nervous and reproductive systems, kidney, pancreas, lung, bone, intestine, among others. TRP channels are finely modulated by different mechanisms: regulation of their function and/or by control of their expression or cellular/subcellular localization. These mechanisms are subject to being affected by several endogenously-produced compounds, some of which are of a lipidic nature such as steroids. Fascinatingly, steroids and TRP channels closely interplay to modulate several physiological events. Certain TRP channels are affected by the typical genomic long-term effects of steroids but others are also targets for non-genomic actions of some steroids that act as direct ligands of these receptors, as will be reviewed here.

Human dehydrogenase/reductase SDR family member 11 (DHRS11) and aldo-keto reductase 1C isoforms in comparison: Substrate and reaction specificity in the reduction of 11-keto-C19-steroids

Recent studies have shown that an adrenal steroid 11β-hydroxy-4-androstene-3,17-dione serves as the precursor to androgens, 11-ketotestosterone and 11-ketodihydrotestosterone (11KDHT). The biosynthetic pathways include the reduction of 3- and 17-keto groups of the androgen precursors 11-keto-C₁₉-steroids, which has been reported to be mediated by three human enzymes; aldo-keto reductase (AKR)1C2, AKR1C3 and 17β-hydroxysteroid dehydrogenase (HSD) type-3. To explore the contribution of the enzymes in the reductive metabolism, we kinetically compared the substrate specificity for 11-keto-C₁₉-steroids among purified recombinant preparations of four AKRs (1C1, 1C2,1C3 and 1C4) and DHRS11, which shows 17β-HSD activity. Although AKR1C1 did not reduce the 11-keto-C₁₉-steroids, AKR1C3 and DHRS11 reduced 17-keto groups of 11-keto-4-androstene-3,17-dione, 11-keto-5α-androstane-3,17-dione (11K-Adione) and 11-ketoandrosterone with K_m values of 5-28 μM. The 3-keto groups of 11KDHT and 11K-Adione were reduced by AKR1C4 (K_m 1 μM) more efficiently than by AKR1C2 (K_m 5 and 8 μM, respectively). GC/MS analysis of the products showed that DHRS11 acts as 17β-HSD, and that AKR1C2 and AKR1C4 are predominantly 3α-HSDs, but formed a minor 3β-metabolite from 11KDHT. Since DHRS11 was thus newly identified as 11-keto-C₁₉-steroid reductase, we also investigated its substrate-binding mode by molecular docking and site-directed mutagenesis of Thr163 and Val200, and found the following structural features: 1). There is a space that accommodates the 11-keto group of the 11-keto-C₁₉-steroids in the substrate-binding site. 2) Val200 is a critical determinant for exhibiting the strict 17β-HSD activity of the enzyme, because the Val200Leu mutation resulted in both significant impairment of the 17β-HSD activity and emergence of 3β-HSD activity towards 5α-androstanes including 11KDHT.

Imidacloprid disrupts the endocrine system by interacting with androgen receptor in male mice

In the current study, six-week-old male ICR mice were administered imidacloprid (IMI) at concentrations of 3, 10 and 30 mg/L for a duration of 10 weeks to investigate the toxicity of IMI on the endocrine system. We observed that testicular morphology was severely impaired and damaged, and the levels of serum testosterone (T) and the expression of androgen receptor (AR) decreased significantly. Molecular docking analysis suggested that IMI docks into the active site of AR successfully and that three key hydrogen bonds were formed with the active site residues Glu11, Gln41 and Lys138. The binding free energy value of the AR-IMI complex suggested a stable binding between IMI and AR. All these results indicated that IMI could interact with AR. In addition, major genes in the testis involved in the synthesis of cholesterol and T were generally inhibited, and the serum cholesterol sources were also reduced. Moreover, the aromatase in male mice was lacking after subchronic IMI exposure. The data acquired from the present study indicated that IMI could lead to endocrine disruption by interacting with AR and influence the expression of genes involved in the production of T in male mice.

Testosterone modulates renal ammonia metabolism

There are substantial sex differences in renal structure and ammonia metabolism that correlate with differences in expression of proteins involved in ammonia generation and transport. This study determined the role of testis-derived testosterone in these differences. We studied 4-mo-old male C57BL/6 mice 4 and 8 wk after either bilateral orchiectomy (ORCH) or sham-operated control surgery and determined the effect of testosterone replacement to reverse the effects of ORCH. Finally, we determined the cellular expression of androgen receptor (AR), testosterone's canonical target receptor. ORCH decreased kidney and proximal tubule size, and testosterone replacement reversed this effect. ORCH increased ammonia excretion in a testosterone-dependent fashion; this occurred despite similar food intake, which is the primary component of endogenous acid production. ORCH increased expression of both phosphoenolpyruvate, a major ammonia-generating protein, and Na⁺-K⁺-2Cl^- cotransporter, which mediates thick ascending limb ammonia reabsorption; these changes were reversed with testosterone replacement. Orchiectomy also decreased expression of Na⁺/H⁺ exchanger isoform 3, which mediates proximal tubule ammonia secretion, in a testosterone-dependent pattern. Finally, ARs are expressed throughout the proximal tubule in both the male and female kidney. Testosterone, possibly acting through ARs, has dramatic effects on kidney and proximal tubule size and decreases ammonia excretion through its effects on several key proteins involved in ammonia metabolism.

Human efflux transport of testosterone, epitestosterone and other androgen glucuronides

Several drug-metabolizing enzymes are known to control androgen homeostasis in humans. UDP-glucuronosyltransferases convert androgens to glucuronide conjugates in the liver and intestine, which enables subsequent elimination of these conjugated androgens via urine. The most important androgen is testosterone, while others are the testosterone metabolites androsterone and etiocholanolone, and the testosterone precursor dehydroepiandrosterone. Epitestosterone is another endogenous androgen, which is included as a crucial marker in urine doping tests. Since glucuronide conjugates are hydrophilic, efflux transporters mediate their excretion from tissues. In this study, we employed the membrane vesicle assay to identify the efflux transporters for glucuronides of androsterone, dehydroepiandrosterone, epitestosterone, etiocholanolone and testosterone. The human hepatic and intestinal transporters MRP2 (ABCC2), MRP3 (ABCC3), MRP4 (ABCC4), BCRP (ABCG2) and MDR1 (ABCB1) were studied in vitro. Of these transporters, only MRP2 and MRP3 transported the androgen glucuronides investigated. In kinetic analyses, MRP3 transported glucuronides of androsterone, epitestosterone and etiocholanolone at low K_m values, between 0.4 and 4 μM, while the K_m values for glucuronides of testosterone and dehydroepiandrosterone were 14 and 51 μM, respectively. MRP2 transported the glucuronides at lower affinity, as indicated by K_m values over 100 μM. Interestingly, the MRP2-mediated transport of androsterone and epitestosterone glucuronides was best described by sigmoidal kinetics. The inability of BCRP to transport any of the androgen glucuronides investigated is drastically different from its highly active transport of several estrogen conjugates. Our results explain the transporter-mediated disposition of androgen glucuronides in humans, and shed light on differences between the human efflux transporters MRP2, MRP3, MRP4, BCRP and MDR1.

Normalized Testosterone Glucuronide as a Potential Urinary Biomarker for Highly Variable UGT2B17 in Children 7-18 Years

UDP-glucuronosyltransferase 2B17 (UGT2B17) is a highly variable androgen-metabolizing and drug-metabolizing enzyme. UGT2B17 exhibits a unique ontogeny profile characterized by a dramatic increase in hepatic protein expression from prepubertal age to adulthood. Age, sex, copy number variation (CNV), and single nucleotide polymorphisms only explain 26% of variability in protein expression, highlighting the need for a phenotypic biomarker for predicting interindividual variability in glucuronidation of UGT2B17 substrates. Here, we propose testosterone glucuronide (TG) normalized by androsterone glucuronide (TG/AG) as a urinary UGT2B17 biomarker, and examine the associations among urinary TG/AG and age, sex, and CNV. We performed targeted metabolomics of 12 androgen conjugates with liquid-chromatography tandem mass spectrometry in 63 pediatric subjects ages 7-18 years followed over 7 visits in 3 years. Consistent with the reported developmental trajectory of UGT2B17 protein expression, urinary TG/AG is significantly associated with age, sex, and CNV. In conclusion, TG/AG shows promise as a phenotypic urinary UGT2B17 biomarker.

Intracrinology-revisited and prostate cancer

The formation of steroid hormones in peripheral target tissues is referred to as their intracrine formation. This process occurs in hormone dependent malignancies such as prostate and breast cancer in which the disease can be either castrate resistant or occur post-menopausally, respectively. In these instances, the major precursor steroid of androgens and estrogens is dehydroepiandrosterone (DHEA) and DHEA-SO4. This article reviews the major pathways by which adrenal steroids are converted to the potent male sex hormones, testosterone (T) and 5α-dihydrotestosterone (5α-DHT) and the discrete enzyme isoforms involved in castration resistant prostate cancer. Previous studies have mainly utilized radiotracers to investigate these pathways but have not used prevailing concentrations of precursors found in castrate male human serum. In addition, the full power of stable-isotope dilution liquid chromatography tandem mass spectrometry has not been applied routinely. Furthermore, it is clear that adaptive responses occur in the transporters and enzyme isoforms involved in response to androgen deprivation therapy that need to be considered.

Androgen Effects on the Adrenergic System of the Vascular, Airway, and Cardiac Myocytes and Their Relevance in Pathological Processes

INTRODUCTION

Androgen signaling comprises nongenomic and genomic pathways. Nongenomic actions are not related to the binding of the androgen receptor (AR) and occur rapidly. The genomic effects implicate the binding to a cytosolic AR, leading to protein synthesis. Both events are independent of each other. Genomic effects have been associated with different pathologies such as vascular ischemia, hypertension, asthma, and cardiovascular diseases. Catecholamines play a crucial role in regulating vascular smooth muscle (VSM), airway smooth muscle (ASM), and cardiac muscle (CM) function and tone.

OBJECTIVE

The aim of this review is an updated analysis of the role of androgens in the adrenergic system of vascular, airway, and cardiac myocytes. Body. Testosterone (T) favors vasoconstriction, and its concentration fluctuation during life stages can affect the vascular tone and might contribute to the development of hypertension. In the VSM, T increases α1-adrenergic receptors (α ₁-ARs) and decreases adenylyl cyclase expression, favoring high blood pressure and hypertension. Androgens have also been associated with asthma. During puberty, girls are more susceptible to present asthma symptoms than boys because of the increment in the plasmatic concentrations of T in young men. In the ASM, β ₂-ARs are responsible for the bronchodilator effect, and T augments the expression of β ₂-ARs evoking an increase in the relaxing response to salbutamol. The levels of T are also associated with an increment in atherosclerosis and cardiovascular risk. In the CM, activation of α _1A-ARs and β ₂-ARs increases the ionotropic activity, leading to the development of contraction, and T upregulates the expression of both receptors and improves the myocardial performance.

CONCLUSIONS

Androgens play an essential role in the adrenergic system of vascular, airway, and cardiac myocytes, favoring either a state of health or disease. While the use of androgens as a therapeutic tool for treating asthma symptoms or heart disease is proposed, the vascular system is warmly affected.

Implicating androgen excess in propagating metabolic disease in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) has been traditionally perceived as a reproductive disorder due to its most common presentation with menstrual dysfunction and infertility. However, it is now clear that women with PCOS are at increased risk of metabolic dysfunction, from impaired glucose tolerance and type 2 diabetes mellitus to nonalcoholic fatty liver disease and cardiovascular disease. PCOS is characterised by androgen excess, with cross-sectional data showing that hyperandrogenism is directly complicit in the development of metabolic complications. Recent studies have also shown that C11-oxy _C19 androgens are emerging to be clinically and biochemically significant in PCOS, thus emphasising the importance of understanding the impact of both classic and C11-oxy _C19 androgens on women's health. Here we discuss androgen metabolism in the context of PCOS, and dissect the role played by androgens in the development of metabolic disease through their effects on metabolic target tissues in women.

Sex, Gender, and Sex Hormones in Pulmonary Hypertension and Right Ventricular Failure

Pulmonary hypertension (PH) encompasses a syndrome of diseases that are characterized by elevated pulmonary artery pressure and pulmonary vascular remodeling and that frequently lead to right ventricular (RV) failure and death. Several types of PH exhibit sexually dimorphic features in disease penetrance, presentation, and progression. Most sexually dimorphic features in PH have been described in pulmonary arterial hypertension (PAH), a devastating and progressive pulmonary vasculopathy with a 3-year survival rate <60%. While patient registries show that women are more susceptible to development of PAH, female PAH patients display better RV function and increased survival compared to their male counterparts, a phenomenon referred to as the "estrogen paradox" or "estrogen puzzle" of PAH. Recent advances in the field have demonstrated that multiple sex hormones, receptors, and metabolites play a role in the estrogen puzzle and that the effects of hormone signaling may be time and compartment specific. While the underlying physiological mechanisms are complex, unraveling the estrogen puzzle may reveal novel therapeutic strategies to treat and reverse the effects of PAH/PH. In this article, we (i) review PH classification and pathophysiology; (ii) discuss sex/gender differences observed in patients and animal models; (iii) review sex hormone synthesis and metabolism; (iv) review in detail the scientific literature of sex hormone signaling in PAH/PH, particularly estrogen-, testosterone-, progesterone-, and dehydroepiandrosterone (DHEA)-mediated effects in the pulmonary vasculature and RV; (v) discuss hormone-independent variables contributing to sexually dimorphic disease presentation; and (vi) identify knowledge gaps and pathways forward. © 2020 American Physiological Society. Compr Physiol 10:125-170, 2020.

Genomic and transcriptomic insights into molecular basis of sexually dimorphic nuptial spines in Leptobrachium leishanense

Sexually dimorphic (SD) traits are important in sexual selection and species survival, yet the molecular basis remains elusive, especially in amphibians where SD traits have evolved repeatedly. We focus on the Leishan moustache toad (Leptobrachium leishanense), in which males develop nuptial spines on their maxillary skin. Here we report a 3.5 Gb genome assembly with a contig N50 of 1.93 Mb. We find a specific expansion of the intermediate filament gene family including numerous keratin genes. Within these genes, a cluster of duplicated hair keratin genes exhibits male-biased and maxillary skin-specific expression, suggesting a role in developing nuptial spines. We identify a module of coexpressed genes significantly associated with spine formation. In addition, we find several hormones likely to be involved in regulating spine development. This study not only presents a high-quality anuran genome but also provides a reference for studying skin-derived SD traits in amphibians.

The basis of sexual dimorphism in non-model species may be elusive, in part due to a lack of genomic and molecular resources. Here, Li et al. report a high-quality anuran genome and reveal candidate genes and pathways associated with shaping sexually dimorphic nuptial spines in a moustache toad.

Update on adrenal steroid hormone biosynthesis and clinical implications

Steroid biosynthesis is a complex process in which cholesterol is converted to steroid hormones with the involvement of multiple enzymes and cofactors. Inborn conditions affecting adrenal steroidogenesis are relatively common in paediatric practice and have serious implications on patient mortality and morbidity. This paper provides an overview of novel insights into human adrenal steroid biosynthesis. Inborn errors of steroidogenesis associated with congenital adrenal hyperplasia are discussed, with a particular focus on the pathophysiology and clinical features of 21-hydroxylase deficiency. The final section of the review presents more recent findings and clinical implications of adrenal-specific androgen biosynthesis.

The gut microbiota is a major regulator of androgen metabolism in intestinal contents

Androgens exert important effects both in androgen-responsive tissues and in the intestinal tract. To determine the impact of the gut microbiota (GM) on intestinal androgen metabolism, we measured unconjugated (free) and glucuronidated androgen levels in intestinal contents from the small intestine, with a low bacterial density, and from cecum and colon, with a high bacterial density. Using a specific, sensitive gas chromatography-tandem mass spectrometry method, we detected high levels of glucuronidated testosterone (T) and dihydrotestosterone (DHT) in small intestinal content of mice of both sexes, whereas in the distal intestine we observed remarkably high levels of free DHT, exceeding serum levels by >20-fold. Similarly, in young adult men high levels of unconjugated DHT, >70-fold higher than in serum, were detected in feces. In contrast to mice with a normal GM composition, germ-free mice had high levels of glucuronidated T and DHT, but very low free DHT levels, in the distal intestine. These findings demonstrate that the GM is involved in intestinal metabolism and deglucuronidation of DHT and T, resulting in extremely high free levels of the most potent androgen, DHT, in the colonic content of young and healthy mice and men.

Posttranslational regulation of androgen dependent and independent androgen receptor activities in prostate cancer

Prostate cancer (PCa) is the most commonly diagnosed cancer among men in western countries. Androgen receptor (AR) signaling plays key roles in the development of PCa. Androgen deprivation therapy (ADT) remains the standard therapy for advanced PCa. In addition to its ligand androgen, accumulating evidence indicates that posttranscriptional modification is another important mechanism to regulate AR activities during the progression of PCa, especially in castration resistant prostate cancer (CRPC). To date, a number of posttranscriptional modifications of AR have been identified, including phosphorylation (e.g. by CDK1), acetylation (e.g. by p300 and recognized by BRD4), methylation (e.g. by EZH2), ubiquitination (e.g. by SPOP), and SUMOylation (e.g. by PIAS1). These modifications are essential for the maintenance of protein stability, nuclear localization and transcriptional activity of AR. This review summarizes posttranslational modifications that influence androgen-dependent and -independent activities of AR, PCa progression and therapy resistance. We further emphasize that in addition to androgen, posttranslational modification is another important way to regulate AR activity, suggesting that targeting AR posttranslational modifications, such as proteolysis targeting chimeras (PROTACs) of AR, represents a potential and promising alternate for effective treatment of CRPC. Potential areas to be investigated in the future in the field of AR posttranslational modifications are also discussed.

Human steroid biosynthesis, metabolism and excretion are differentially reflected by serum and urine steroid metabolomes: A comprehensive review

Advances in technology have allowed for the sensitive, specific, and simultaneous quantitative profiling of steroid precursors, bioactive steroids and inactive metabolites, facilitating comprehensive characterization of the serum and urine steroid metabolomes. The quantification of steroid panels is therefore gaining favor over quantification of single marker metabolites in the clinical and research laboratories. However, although the biochemical pathways for the biosynthesis and metabolism of steroid hormones are now well defined, a gulf still exists between this knowledge and its application to the measured steroid profiles. In this review, we present an overview of steroid hormone biosynthesis and metabolism by the liver and peripheral tissues, specifically highlighting the pathways linking and differentiating the serum and urine steroid metabolomes. A brief overview of the methodology used in steroid profiling is also provided.

Effect of SULT2B1 genetic polymorphisms on the sulfation of dehydroepiandrosterone and pregnenolone by SULT2B1b allozymes

Pregnenolone and dehydroepiandrosterone (DHEA) are hydroxysteroids that serve as biosynthetic precursors for steroid hormones in human body. SULT2B1b has been reported to be critically involved in the sulfation of pregnenolone and DHEA, particularly in the sex steroid-responsive tissues. The current study was designed to investigate the impact of the genetic polymorphisms of SULT2B1 on the sulfation of DHEA and pregnenolone by SULT2B1b allozymes. Ten SULT2B1b allozymes previously prepared were shown to exhibit differential sulfating activities toward DHEA and pregnenolone in comparison to the wild-type enzyme. Kinetic studies revealed further significant changes in their substrate-binding affinity and catalytic activity toward DHEA and pregnenolone. Taken together, these results indicated clearly a profound effect of SULT2B1 genetic polymorphisms on the sulfating activity of SULT2B1b allozymes toward DHEA and pregnenolone, which may have implications in inter-individual variations in the homeostasis of these two important steroid precursors.

Cyclophilin D participates in the inhibitory effect of high-fat diet on the expression of steroidogenic acute regulatory protein

OBJECTIVE

The high-fat diet (HFD)-induced obesity is responsible for the testosterone deficiency (TD). However, the mechanism remains unknown. Mitochondrial homeostasis is proved to be important for maintaining the function of steroidogenic acute regulatory protein (StAR), the first rate-limiting enzyme in testosterone synthesis. As the key regulator of mitochondrial membrane permeability, cyclophilin D (CypD) plays a crucial role in maintaining mitochondrial function. In this study, we sought to elucidate the role of CypD in the expression of StAR affected by HFD.

METHODS

To analyse the influence of CypD on StAR in vivo and in vitro, mouse models of HFD, CypD overexpression and CypD knockout (Ppif-/- ) as well as Leydig cells treated with palmitic acid (PA) and CypD overexpression plasmids were examined with an array of metabolic, mitochondrial function and molecular assays.

RESULTS

Compared with the normal diet mice, consistent with reduced testosterone in testes, the expressions of StAR in both mRNA and protein levels in HFD mice were down-regulated, while expressions of CypD were up-regulated. High-fat intake impaired mitochondrial function with the decrease in StAR in Leydig cells. Overexpression of CypD inhibited StAR expressions in vivo and in vitro. Compared with C57BL/6 mice with HFD, expressions of StAR were improved in Ppif-/- mice with HFD.

CONCLUSIONS

Mitochondrial CypD involved in the inhibitory effect of HFD on StAR expression in testes.

The Colorful Diversity of Thyroid Hormone Metabolites

Since the discovery of L-thyroxine, the main secretory product of the thyroid gland, and its major metabolite T3, which exerts the majority of thyroid hormone action via ligand-dependent modulation of the function of T3 receptors in nuclei, mitochondria, and other subcellular compartments, various other T4-derived endogenous metabolites have been identified in blood and tissues of humans, animals, and early protochordates. This review addresses major historical milestones and experimental findings resulting in the discovery of the key enzymes of thyroid hormone metabolism, the three selenoprotein deiodinases, as well as the decarboxylases and amine oxidases involved in formation and degradation of recently identified endogenous thyroid hormone metabolites, i.e. 3-iodothyronamine and 3-thyroacetic acid. The concerted action of deiodinases 2 and 3 in regulation of local T3 availability is discussed. Special attention is given to the role of the thyromimetic "hot" metabolite 3,5-T2 and the "cool" 3-iodothyronamine, especially after administration of pharmacological doses of these endogenous thyroid hormone metabolites in various animal experimental models. In addition, available information on the biological roles of the two major acetic acid derivatives of thyroid hormones, i.e. Tetrac and Triac, as well as sulfated metabolites of thyroid hormones is reviewed. This review addresses the consequences of the existence of this broad spectrum of endogenous thyroid hormone metabolites, the "thyronome," beyond the classical thyroid hormone profile comprising T4, T3, and rT3 for appropriate analytical coverage and clinical diagnostics using mass spectrometry versus immunoassays for determination of total and free concentrations of thyroid hormone metabolites in blood and tissues.

A liquid chromatography-tandem mass spectrometry assay for the profiling of classical and 11-oxygenated androgens in saliva

Background

Classical and 11-oxygenated androgens both contribute to the androgen pool. Regular monitoring of the androgen status is required in disorders of steroidogenesis, and multiplexing of androgens improves the diagnostic ability of an assay. Due to the cheap non-invasive collection, saliva is advantageous when multiple samples are required. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) offers sensitive, simultaneous quantification of steroids with short run times. Here, we have developed an LC-MS/MS assay for the simultaneous measurement of 17-hydroxyprogesterone, androstenedione, testosterone, 11β-hydroxyandrostenedione and 11-ketotestosterone in saliva.

Methods

Samples (300 μL unstimulated whole saliva) were prepared by supported liquid extraction with dichloromethane and were reconstituted in 40% methanol. After online solid phase extraction with C18 cartridges, liquid chromatography was performed on a C8 column using a water/methanol gradient containing 0.1% formic acid and 2 mmol/L ammonium acetate. A Waters TQ-S mass spectrometer was used for quantification.

Results

Total run time was 6.4 min. For all analytes, recovery was between 89% and 109%, ion suppression between 86% and 105%. Intra- and inter-assay comparisons showed a coefficient of variation <10% and the bias between measured and nominal concentration varied between –8% and 10%. Interference with a large set of natural and synthetic steroids was excluded. The assay was applied for the measurement of the androgen profile in healthy men ( n = 17) and women ( n = 10) which confirmed the sensitivity of the assay to be appropriate.

Conclusion

We present a novel LC-MS/MS assay for the comprehensive profiling of classical and 11-oxygenated androgens with potential for routine clinical application.

Applying mass spectrometric methods to study androgen biosynthesis and metabolism in prostate cancer

Recent development of gas chromatography and liquid chromatography-tandem mass spectrometry (GC-MS/MS, LC-MS/MS) has provided novel tools to define sex steroid concentrations. These new methods overcome several of the problems associated with immunoassays for sex steroids. With the novel MS-based applications we are now able to measure small concentrations of the steroid hormones reliably and with high accuracy in both body fluids and tissue homogenates. The sensitivity of the tandem mass spectrometry assays allows us also for the first time to reliably measure picomolar or even femtomolar concentrations of estrogens and androgens. Furthermore, due to a high sensitivity and specificity of MS technology, we are also able to measure low concentrations of steroid hormones of interest in the presence of pharmacological concentration of other steroids and structurally closely related compounds. Both of these features are essential for multiple preclinical models for prostate cancer. The MS assays are also valuable for the simultaneous measurement of multiple steroids and their metabolites in small sample volumes in serum and tissue biopsies of prostate cancer patients before and after drug interventions. As a result, novel information about steroid hormone synthesis and metabolic pathways in prostate cancer has been obtained. In our recent studies, we have extensively applied a GC-MS/MS method to study androgen biosynthesis and metabolism in VCaP prostate cancer xenografts in mice. In the present review, we shortly summarize some of the benefits of the GC-MS/MS and novel LC-MS/MS assays, and provide examples of their use in defining novel mechanisms of androgen action in prostate cancer.

Effect of a multi-ingredient based food supplement on sexual function in women with low sexual desire

Background

Studies have demonstrated that women with low desire and low excitement have negative feelings regarding their physical and emotional satisfaction, as well as their happiness. In this study, we evaluate the efficacy of Libicare® - a multi-ingredient food supplement - to improve sexual function in postmenopausal women.

Methods

This was an exploratory, prospective, non-controlled, observational study. Postmenopausal women aged 45–65 with a risk of sexual dysfunction (Female Sexual Function Index (FSFI) < 25.83) were included during routine clinical visits and treated with 2 tablets of Libicare® daily for 2 months. Libicare® is an oral food supplement containing Trigonella foenum graecum, Turnera diffusa, Tribulus terrestris, and Ginkgo biloba dry extracts. Primary endpoint: change vs. baseline in FSFI score. Secondary endpoints: 1) changes in testosterone and serum steroid levels of free testosterone and sex hormone-binding globulin (SHBG) levels and 2) tolerability.

Results

A total of 29 patients (mean age: 54.69 years) were included. FSFI mean (SD) score showed a significant increase: 20.15 (4.48) vs 25.03 (6.94), baseline vs final; p = 0.0011, paired t-test. Most patients (86.2%) increased their FSFI score. All FSFI domains, except dyspareunia, showed significant increases. The highest increase was observed in the desire domain (p = 0.0004). Testosterone and SHBG levels were assessed in 21 patients. A significant increase in testosterone level was observed: 0.41 (0.26) vs. 0.50 (0.34) pg/mL, baseline vs. final; p = 0.038, Wilcoxon test. 52.4% of patients increased their testosterone levels. Finally, a significant decrease was observed in SHBG level: 85 (32.9) vs. 73 (26.8) nmol/L, baseline vs. final; p = 0.0001; paired t-test. 95.2% of patients decreased their SHBG levels.

Conclusion

In this pilot study, a significant improvement in sexual function and related hormone levels was observed with Libicare®. Further studies must be conducted to confirm these exciting results.

Trial registration

Current Controlled Trial ISRCTN12928573. Date of registration: 28/March/2019. Retrospectively registered.

Reproductive Endocrinology of Nonalcoholic Fatty Liver Disease

The liver and the reproductive system interact in a multifaceted bidirectional fashion. Sex steroid signaling influences hepatic endobiotic and xenobiotic metabolism and contributes to the pathogenesis of functional and structural disorders of the liver. In turn, liver function affects the reproductive axis via modulating sex steroid metabolism and transport to tissues via sex hormone-binding globulin (SHBG). The liver senses the body's metabolic status and adapts its energy homeostasis in a sex-dependent fashion, a dimorphism signaled by the sex steroid milieu and possibly related to the metabolic costs of reproduction. Sex steroids impact the pathogenesis of nonalcoholic fatty liver disease, including development of hepatic steatosis, fibrosis, and carcinogenesis. Preclinical studies in male rodents demonstrate that androgens protect against hepatic steatosis and insulin resistance both via androgen receptor signaling and, following aromatization to estradiol, estrogen receptor signaling, through regulating genes involved in hepatic lipogenesis and glucose metabolism. In female rodents in contrast to males, androgens promote hepatic steatosis and dysglycemia, whereas estradiol is similarly protective against liver disease. In men, hepatic steatosis is associated with modest reductions in circulating testosterone, in part consequent to a reduction in circulating SHBG. Testosterone treatment has not been demonstrated to improve hepatic steatosis in randomized controlled clinical trials. Consistent with sex-dimorphic preclinical findings, androgens promote hepatic steatosis and dysglycemia in women, whereas endogenous estradiol appears protective in both men and women. In both sexes, androgens promote hepatic fibrosis and the development of hepatocellular carcinoma, whereas estradiol is protective.

Study of the association of DHEAS, testosterone and cortisol with S-Klotho plasma levels in healthy sedentary middle-aged adults

BACKGROUND

α-Klotho is a recently discovered gene that accelerates ageing when disrupted and extends lifespan when overexpressed. The age-related decline in DHEAS and testosterone secretion and the increase in cortisol are associated with a rise of frailty and mortality.

OBJECTIVE

To investigate the association of DHEAS, cortisol and testosterone plasma levels with S-Klotho plasma levels in healthy sedentary middle-aged adults.

METHODS

73 (39 women) healthy middle-aged sedentary adults (45-65 years old) were recruited for the present study. The blood samples were collected in the morning after fasting for 12 h.

RESULTS

DHEAS was positively associated with S-Klotho in men (β = 0.521, R² = 0.248, P = 0.002), whereas no association was observed in women (P ≥ 0.201). Testosterone was positively associated with S-Klotho in both men and women (β = 0.360, R² = 0.099, P = 0.047; β = 0.431, R² = 0.161, P = 0.010, respectively). No association was found between cortisol and S-Klotho neither in men nor in women (all P ≥ 0.141). The association between DHEAS and testosterone with S-Klotho in men disappeared after adjusting by age (all P ≥ 0.151). Nevertheless, the association between testosterone (β = 0.397, R² = 0.423, P = 0.011) and S-Klotho in women remained after adjusting by age.

CONCLUSIONS

DHEAS and testosterone were positively associated with S-Klotho in healthy sedentary middle-aged men while only testosterone was positively associated in women.

Androgen receptor: A promising therapeutic target in breast cancer

Breast cancer (BCa) is the second most common cancer worldwide and the most prevalent cancer in women. The majority of BCa cases are positive (+) for the estrogen receptor (ER⁺, 80%) and progesterone receptor (PR⁺, 65%). Estrogen and progesterone hormones are known to be involved in cancer progression, and thus hormonal deprivation is used as an effective treatment for ER⁺PR⁺ BCa subtypes. However, some ER⁺PR⁺ BCa patients develop resistance to such therapies. Meanwhile, chemotherapy is the only available treatment for ER^-PR^- BCa tumors. Another hormone receptor known as the androgen receptor (AR) has also been found to be widely expressed in human breast carcinomas. However, the mechanisms of AR and its endogenous androgen ligands is not well-understood in BCa and its biological role in this hormone-related disease remains unclear. In this review, we aim to address the importance of the AR in BCa diagnosis and prognosis, current AR-targeting approaches in BCa, and the potential for AR-downstream molecules to serve as therapeutic targets.

Exogenous Testosterone Does Not Influence 11-Oxygenated C19 Steroid Concentrations in Healthy Postmenopausal Women

Context

11β-Hydroxyandrostenedione (11OHA4), 11β-hydroxytestosterone (11OHT), and their respective peripheral derivatives, 11-ketoandrostenedione (11KA4) and 11-ketotesosterone (11KT), have been implicated in androgen-related physiopathology. Little is known of these steroids in postmenopausal women or whether exogenous testosterone therapy influences their levels.

Objective

The impact of exogenous testosterone on serum levels of 11-oxygenated steroids was determined in healthy postmenopausal women.

Participants and Methods

Levels of 19-carbon (C19) steroids were measured by liquid chromatography–tandem mass spectrometry in serum obtained at baseline and at 12 and 26 weeks from 73 healthy postmenopausal women, aged 55 to 65 years, who participated in a randomized, double-blind, placebo-controlled clinical trial assessing the effects of transdermal testosterone on cognitive performance.

Results

Of the 11-oxygenated androgens, 11OHA4 was the most abundant (median, 6.46 nmol/L; range, 1.51 to 23.82 nmol/L), with concentrations several fold greater than its precursor androstenedione (median, 1.38 nmol/L; range, 0.52 to 2.92 nmol/L). Baseline median (range) testosterone and 11KT levels were similar [0.56 (0.23 to 1.48) nmol/L; 0.85 (0.25 to 2.86) nmol/L, respectively). 11OHT was closely correlated with 11KT (Spearman rank correlation coefficient, 0.79; P < 0.001) and 11OHA4 correlated with 11KA4 (Spearman rank correlation coefficient, 0.73; P < 0.001). Testosterone therapy resulted in an increase in serum testosterone level, whereas all 11-oxygenated androgens remained unchanged throughout the 26 weeks of treatment.

Conclusion

After menopause, the adrenal production of 11-oxygenated derivatives of androstenedione and testosterone contributes importantly to the total circulating androgen pool. Exogenous testosterone does not influence the circulating levels 11-oxygenated C19 steroids.

Increased body fat mass and androgen metabolism - A twin study in healthy young women

OBJECTIVE

Obesity may alter serum steroid concentrations and metabolism. We investigated this in healthy young women with increased body fat and their leaner co-twin sisters.

DESIGN

Age and genetic background both strongly influence serum steroid levels and body composition. This is a cross-sectional study of 13 female monozygotic twin pairs (age, 23-36 years), ten of which were discordant for body mass index (median difference in body weight between the co-twins, 19 kg).

METHODS

We determined body composition by dual energy X-ray absorptiometry and magnetic resonance imaging, serum androgens by liquid chromatography-tandem mass spectrometry, and mRNA expression of genes in subcutaneous adipose tissue and adipocytes.

RESULTS

The heavier women had lower serum dehydroepiandrosterone (DHEA), dihydrotestosterone (DHT), and sex hormone-binding globulin (SHBG) (P < 0.05 for all) compared to their leaner co-twins with no differences in serum testosterone or androstenedione levels. Serum DHEA correlated inversely with %body fat (r = -0.905, P = 0.002), and DHT positively with SHBG (r = 0.842, P = 0.002). In adipose tissue or adipocytes, expressions of STS (steroid sulfatase) and androgen-related genes were significantly higher in the heavier compared to the leaner co-twin, and within pairs, correlated positively with adiposity but were not related to serum androgen levels. None of the serum androgen or SHBG levels correlated with indices of insulin resistance.

CONCLUSIONS

Serum DHEA levels were best predicted by %body fat, and serum DHT by SHBG. These or other serum androgen concentrations did not reflect differences in androgen-related genes in adipose tissue. General or intra-abdominal adiposity were not associated with increased androgenicity in young women.

Endometrial Intracrinology: Oestrogens, Androgens and Endometrial Disorders

Peripheral tissue metabolism of steroids (intracrinology) is now accepted as a key way in which tissues, such as the endometrium, can utilise inactive steroids present in the blood to respond to local physiological demands and 'fine-tune' the activation or inhibition of steroid hormone receptor-dependent processes. Expression of enzymes that play a critical role in the activation and inactivation of bioactive oestrogens (E1, E2) and androgens (A4, T, DHT), as well as expression of steroid hormone receptors, has been detected in endometrial tissues and cells recovered during the menstrual cycle. There is robust evidence that increased expression of aromatase is important for creating a local microenvironment that can support a pregnancy. Measurement of intra-tissue concentrations of steroids using liquid chromatography⁻tandem mass spectrometry has been important in advancing our understanding of a role for androgens in the endometrium, acting both as active ligands for the androgen receptor and as substrates for oestrogen biosynthesis. The emergence of intracrinology, associated with disordered expression of key enzymes such as aromatase, in the aetiology of common women's health disorders such as endometriosis and endometrial cancer has prompted renewed interest in the development of drugs targeting these pathways, opening up new opportunities for targeted therapies and precision medicine.

Quantitative characterization of UDP-glucuronosyltransferase 2B17 in human liver and intestine and its role in testosterone first-pass metabolism

Protein abundance and activity of UGT2B17, a highly variable drug- and androgen-metabolizing enzyme, were quantified in microsomes, S9 fractions, and primary cells isolated from human liver and intestine by validated LC-MS/MS methods. UGT2B17 protein abundance showed >160-fold variation (mean ± SD, 1.7 ± 2.7 pmol/mg microsomal protein) in adult human liver microsomes (n = 26) and significant correlation (r2 = 0.77, p < 0.001) with testosterone glucuronide (TG) formation. Primary role of UGT2B17 in TG formation compared to UGT2B15 was confirmed by performing activity assays in UGT2B17 gene deletion samples and with a selective UGT2B17 inhibitor, imatinib. Human intestinal microsomes isolated from small intestine (n = 6) showed on average significantly higher protein abundance (7.4 ± 6.6 pmol/mg microsomal protein, p = 0.016) compared to liver microsomes, with an increasing trend towards distal segments of the gastrointestinal (GI) tract. Commercially available pooled microsomes and S9 fractions confirmed greater abundance and activity of UGT2B17 in intestinal fractions compared to liver fractions. To further investigate the quantitative role of UGT2B17 in testosterone metabolism in whole cell system, a targeted metabolomics study was performed in hepatocytes (n = 5) and enterocytes (n = 16). TG was the second most abundant metabolite after androstenedione in both cell systems. Reasonable correlation between UGT2B17 abundance and activity were observed in enterocytes (r2 = 0.69, p = 0.003), but not in hepatocytes. These observational and mechanistic data will be useful in developing physiologically-based pharmacokinetic (PBPK) models for predicting highly-variable first-pass metabolism of testosterone and other UGT2B17 substrates.

SULFATION PATHWAYS: Insights into steroid sulfation and desulfation pathways

Sulfation and desulfation pathways represent highly dynamic ways of shuttling, repressing and re-activating steroid hormones, thus controlling their immense biological potency at the very heart of endocrinology. This theme currently experiences growing research interest from various sides, including, but not limited to, novel insights about phospho-adenosine-5'-phosphosulfate synthase and sulfotransferase function and regulation, novel analytics for steroid conjugate detection and quantification. Within this review, we will also define how sulfation pathways are ripe for drug development strategies, which have translational potential to treat a number of conditions, including chronic inflammatory diseases and steroid-dependent cancers.

Monogenic Disorders of Adrenal Steroidogenesis

Disorders of adrenal steroidogenesis comprise autosomal recessive conditions affecting steroidogenic enzymes of the adrenal cortex. Those are located within the 3 major branches of the steroidogenic machinery involved in the production of mineralocorticoids, glucocorticoids, and androgens. This mini review describes the principles of adrenal steroidogenesis, including the newly appreciated 11-oxygenated androgen pathway. This is followed by a description of pathophysiology, biochemistry, and clinical implications of steroidogenic disorders, including mutations affecting cholesterol import and steroid synthesis, the latter comprising both mutations affecting steroidogenic enzymes and co-factors required for efficient catalysis. A good understanding of adrenal steroidogenic pathways and their regulation is crucial as the basis for sound management of these disorders, which in the majority present in early childhood.