Two simple cleanup methods combined with LC-MS/MS for quantification of steroid hormones in in vivo and in vitro assays

Exposure to topiramate and acetazolamide causes endocrine disrupting effects in female rats during estrus

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a disease characterized by elevated intracranial pressure (ICP) and is a disease of young females. The first line pharmacological treatments include acetazolamide and topiramate and given the nature of IIH patients and the dosing regimen of these drugs, their effect on the endocrine system is important to evaluate. We aimed to assess the effects of acetazolamide and topiramate on steroid profiles in relevant endocrine tissues.

METHODS

Female Sprague Dawley rats received chronic clinically equivalent doses of acetazolamide or topiramate by oral gavage and were sacrificed in estrus. Tissue specific steroid profiles of lateral ventricle CP, 4th ventricle CP, CSF, serum, uterine horn and fundus, ovaries, adrenal glands and pituitary glands were assessed by quantitative targeted LC-MS/MS. We determined luteinizing hormone (LH) and follicle stimulating hormones (FSH) levels in paired serum by ELISA.

RESULTS

Topiramate increased the concentration of estradiol and decreased the concentration of DHEA in lateral choroid plexus. Moreover, it decreased the concentration of androstenediol in the pituitary gland. Topiramate increased serum LH. Acetazolamide decreased progesterone levels in serum and uterine fundus and increased corticosteroid levels in the adrenal glands.

CONCLUSION

These results demonstrate that both acetazolamide and topiramate have endocrine disrupting effects in rats. Topiramate primarily targeted the choroid plexus and the pituitary gland while acetazolamide had broader systemic effects. Furthermore, topiramate predominantly targeted sex hormones, whereas acetazolamide widely affected all classes of hormones. A similar effect in humans has not yet been documented but these concerning findings warrants further investigations.

The intrafollicular concentrations of biologically active cortisol in women rise abruptly shortly before ovulation and follicular rupture

STUDY QUESTION

What is the temporal activity and the concentration in follicular fluid (FF) of the anti-inflammatory steroid cortisol during the ovulatory process in humans?

SUMMARY ANSWER

Intrafollicular concentrations of cortisol become massively upregulated close to ovulation concomitant with an exceptionally high biological activity securing a timely and efficient termination of inflammatory processes.

WHAT IS KNOWN ALREADY

Ovulation has been described as a local, controlled inflammatory process resulting in the degeneration of the follicle wall which facilitate oocyte extrusion. Ovulation also affects the glucocorticoid metabolism of granulosa cells (GCs) and although de novo synthesis of cortisol only occurs in the adrenal cortex, the mid-cycle surge has been shown to induce a change from high expression of HSD11B2, inactivating cortisol to cortisone, to high expression of HSD11B1 which reversibly catalyses cortisol production from cortisone. Furthermore, high concentrations of progesterone and 17OH-progesterone within follicles may cause dislodging of cortisol from cortisol binding protein (CBP) thereby activating the biological activity of cortisol.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study included 50 women undergoing fertility treatment according to a standard antagonist protocol at a university hospital-affiliated fertility clinic in Denmark.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women donated FF and GCs from one follicle for research purpose aspirated at one of four time points during the process of final maturation of follicles: T = 0 h, T = 12 h, T = 17 h, T = 32 h. A second sample was collected at oocyte pick up at T = 36 h. The concentration of cortisol and cortisone together with a range of sex steroids was measured by LC-MS/MS in FF collected at the five time points mentioned above. Whole genome microarray data, validated by q-PCR analysis, was used to evaluate gene expression of CYP11B1, CYP21A2, HSD11B1, HSD11B2, and NR3C1 in GCs at the same time points.

MAIN RESULTS AND THE ROLE OF CHANCE

The concentration of cortisol was significantly increased from a few nM at 0 h to around 100-140 nM (P ≤ 0.0001) at 32-36 h, whilst cortisone was almost constant from 0 to 17 h at a concentration of between 90 and 100 nM being significantly reduced to 25-40 nM (P ≤ 0.0001) at 32-36 h. This was paralleled by a 690-fold upregulation of HSD11B1 from 0 to 12 h increasing to a more than 20.000-fold change at 36 h. HSD11B2 was quickly downregulated 15- to 20-fold after ovulation induction. Concentrations of progesterone and 17OH-progesterone increased during the ovulatory process to high levels which in essence displaces cortisol from its binding protein CBP due to similar binding affinities. Furthermore, a significant decrease in 11-deoxycortisol expression was seen, but CYP11B1 expression was below detection limit in GCs.

LIMITATIONS, REASONS FOR CAUTION

The study included women undergoing ovarian stimulation and results may differ from the natural cycle. More observations at each specific time point may have strengthened the conclusions. Furthermore, we have not been able to measure the actual active biological concentration of cortisol.

WIDER IMPLICATIONS OF THE FINDINGS

For the first time, this study collectively evaluated the temporal pattern of cortisol and cortisone concentrations during human ovulation, rendering a physiological framework for understanding potential dysregulations in the inflammatory reaction of ovulation.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the University Hospital of Copenhagen, Rigshospitalet, and Novo Nordisk Foundation grant number NNF21OC00700556. Interreg V ÔKS through ReproUnion (www.reprounion.eu); Region Zealand Research Foundation. The funders had no role in study design, collection of data, analyses, writing of the article, or the decision to submit it for publication. The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

CSF hyperdynamics in rats mimicking the obesity and androgen excess characteristic of patients with idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a syndrome exhibiting elevated intracranial pressure (ICP), visual disturbances, and severe headache. IIH primarily affects young obese women, though it can occur in individuals of any age, BMI, and sex. IIH is characterized by systemic metabolic dysregulation with a profile of increased androgen hormones. However, the contribution of obesity/hormonal perturbations to cerebrospinal fluid (CSF) dynamics remains unresolved.

METHODS

We employed obese female Zucker rats and adjuvant testosterone to reveal IIH causal drivers. ICP and CSF dynamics were determined with in vivo experimentation and magnetic resonance imaging, testosterone levels assessed with mass spectrometry, and choroid plexus function revealed with transcriptomics.

RESULTS

Obese rats had undisturbed CSF testosterone levels and no changes in ICP or CSF dynamics. Adjuvant testosterone treatment of obese rats elevated the CSF secretion rate, although with no effect on the ICP, due to elevated CSF drainage capacity of these rats.

CONCLUSIONS

Obesity in itself therefore does not suffice to recapitulate the IIH symptoms in rats, but modulation of CSF dynamics appears with adjuvant testosterone treatment, which mimics the androgen excess observed in female IIH patients. Obesity-induced androgen dysregulation may thus contribute to the disease mechanism of IIH and could potentially serve as a future therapeutic target.

Cycle-dependent sex differences in expression of membrane proteins involved in cerebrospinal fluid secretion at rat choroid plexus

BACKGROUND

Female sex is a known risk factor of brain disorders with raised intracranial pressure (ICP) and sex hormones have been suggested to alter cerebrospinal fluid (CSF) dynamics, thus impairing ICP regulation in CSF disorders such as idiopathic intracranial hypertension (IIH). The choroid plexus (CP) is the tissue producing CSF and it has been hypothesized that altered hormonal composition could affect the activity of transporters involved in CSF secretion, thus affecting ICP. Therefore, we aimed to investigate if expression of various transporters involved in CSF secretion at CP were different between males and females and between females in different estrous cycle states. Steroid levels in serum was also investigated.

METHODS

Female and male rats were used to determine sex-differences in the genes encoding for the transporters Aqp1 and 4, NKCC1, NBCe2, NCBE; carbonic anhydrase enzymes II and III (CA), subunits of the Na+/K+-ATPase including Atp1a1, Atp1b1 and Fxyd1 at CP. The estrous cycle stage metestrus (MET) and estrous (ES) were determined before euthanasia. Serum and CP were collected and subjected to RT-qPCR analysis and western blots. Serum was used to measure steroid levels using liquid chromatography tandem mass spectrometry (LC-MS/MS).

RESULTS

Significant differences in gene expression and steroid levels between males and ES females were found, while no differences were found between male and MET females. During ES, expression of Aqp1 was lower (p < 0.01) and NKCC1 was higher in females compared to males. CAII was lower while CAIII was higher in ES females (p < 0.0001). Gene expression of Atp1a1 was lower in ES compared to male (p = 0.0008). Several of these choroidal genes were also significantly different in MET compared to females in ES. Differences in gene expression during the estrus cycle were correlated to serum level of steroid hormones. Protein expression of AQP1 (p = 0.008) and CAII (p = 0.035) was reduced in ES females compared to males.

CONCLUSIONS

This study demonstrates for the first time that expression at CP is sex-dependent and markedly affected by the estrous cycle in female rats. Further, expression was related to hormone levels in serum. This opens a completely new avenue for steroid regulation of the expression of CSF transporters and the close link to the understanding of CSF disorders such as IIH.

Towards a microfluidic H295R steroidogenesis assay-biocompatibility study and steroid detection on a thiol-ene-based chip

The development of cell-based microfluidic assays offers exciting new opportunities in toxicity testing, allowing for integration of new functionalities, automation, and high throughput in comparison to traditional well-plate assays. As endocrine disruption caused by environmental chemicals and pharmaceuticals represents a growing global health burden, the purpose of the current study was to contribute towards the miniaturization of the H295R steroidogenesis assay, from the well-plate to the microfluidic format. Microfluidic chip fabrication with the established well-plate material polystyrene (PS) is expensive and complicated; PDMS and thiol-ene were therefore tested as potential chip materials for microfluidic H295R cell culture, and evaluated in terms of cell attachment, cell viability, and steroid synthesis in the absence and presence of collagen surface modification. Additionally, spike-recovery experiments were performed, to investigate potential steroid adsorption to chip materials. Cell aggregation with poor steroid recoveries was observed for PDMS, while cells formed monolayer cultures on the thiol-ene chip material, with cell viability and steroid synthesis comparable to cells grown on a PS surface. As thiol-ene overall displayed more favorable properties for H295R cell culture, a microfluidic chip design and corresponding cell seeding procedure were successfully developed, achieving repeatable and uniform cell distribution in microfluidic channels. Finally, H295R perfusion culture on thiol-ene chips was investigated at different flow rates (20, 10, and 2.5 µL/min), and 13 steroids were detected in eluting cell medium over 48 h at the lowest flow rate. The presented work and results pave the way for a time-resolved microfluidic H295R steroidogenesis assay.

Modelling idiopathic intracranial hypertension in rats: contributions of high fat diet and testosterone to intracranial pressure and cerebrospinal fluid production

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a condition characterized by increased intracranial pressure (ICP), impaired vision, and headache. Most cases of IIH occur in obese women of childbearing age, though age, BMI, and female sex do not encompass all aspects of IIH pathophysiology. Systemic metabolic dysregulation has been identified in IIH with a profile of androgen excess. However, the mechanistic coupling between obesity/hormonal perturbations and cerebrospinal fluid dynamics remains unresolved.

METHODS

Female Wistar rats were either fed a high fat diet (HFD) for 21 weeks or exposed to adjuvant testosterone treatment for 28 days to recapitulate IIH causal drivers. Cerebrospinal fluid (CSF) and blood testosterone levels were determined with mass spectrometry, ICP and CSF dynamics with in vivo experimentation, and the choroid plexus function revealed with transcriptomics and ex vivo isotope-based flux assays.

RESULTS

HFD-fed rats presented with increased ICP (65%), which was accompanied by increased CSF outflow resistance (50%) without altered CSF secretion rate or choroid plexus gene expression. Chronic adjuvant testosterone treatment of lean rats caused elevated ICP (55%) and CSF secretion rate (85%), in association with increased activity of the choroid plexus Na⁺,K⁺,2Cl^- cotransporter, NKCC1.

CONCLUSIONS

HFD-induced ICP elevation in experimental rats occurred with decreased CSF drainage capacity. Adjuvant testosterone, mimicking the androgen excess observed in female IIH patients, elevated the CSF secretion rate and thus ICP. Obesity-induced androgen dysregulation may thus contribute to the disease mechanism of IIH.

Development of Fe3O4/reduced graphene oxide nanocomposite-based dispersive solid-phase extraction for the quantification of five steroid hormones

Aim: An accurate and sensitive analytical method was proposed to detect some steroid hormones in biological samples. Materials & methods: An Fe₃O₄/reduced graphene oxide nanocomposite-based dispersive solid-phase extraction was developed for the effective and simple preconcentration of steroid hormones from human serum samples. Results & conclusion: The nanocomposite was firstly used as adsorbent to simultaneously extract the selected hormones. Limit of detection values for the selected hormones were calculated between 5.5 and 39.2 ng/kg (mass based). An artificial serum sample was used to test the applicability and accuracy of the developed method; percentage recovery results obtained from two different spiked concentrations were found to be in the range of 80.5-99.9%.

Determination of steroid hormones in grey seal (Halichoerus grypus) blood plasma using convergence chromatography tandem mass spectrometry

A hybrid solid phase extraction (HybridSPE) protocol tailored to ultra-performance convergence chromatography tandem mass spectrometry (UPC²-MS/MS) was developed for the determination of 19 steroid hormones in grey seal (Halichoerus grypus) blood plasma. In this study, the protocol demonstrated acceptable absolute recoveries ranging from 33 to 90%. The chromatographic separation was carried out using a gradient elution program with a total run time of 5 min. For most target analytes, the method repeatability ranged from 1.9 to 24% and the method limits of quantification (mLOQs) ranged from 0.03 to 1.67 ng/mL. A total of 9 plasma samples were analysed to demonstrate the applicability of the developed method, and 13 steroid hormones were quantified in grey seal pup plasma. The most prevalent steroids: cortisol, cortisone, corticosterone, 11-deoxycortisol, progesterone and 17α-hydroxyprogesterone were detected at concentrations in the range of 12.6-40.1, 7.10-24.2, 0.74-10.7, 1.06-5.72, 0.38-4.38 and <mLOQ - 1.01 ng/mL, respectively. To our knowledge, this is the first study to determine steroid hormones in the plasma of pinnipeds using convergence chromatography.

Cortisol in Manure from Cattle Enclosed with Nofence Virtual Fencing

Simple Summary

To increase the efficiency and geographic expansion of nature conservation, large grazers have recently been used, either in the form of wild hoof-bearing animals or as domesticated ruminants including cattle. As part of this, controlling the movement of these animals is essential using either physical or virtual fences to manage the areas of interest. Physical fencing limits migrating wildlife, while using virtual fences with GPS technology paired with collars emitting auditory and electric cues encourages the animals to stay in the desired area without physical restrictions for wild animals. However, virtual fences raise ethical questions regarding the electric impulses emitted by the collar and stress in the fenced animals, we show that the stress hormone cortisol in cow mature is not associated with the use of virtual fencing. We, therefore, conclude that there is no evidence suggesting that cows are stressed from the use of virtual fencing, thus making virtual fencing a reasonable alternative to traditional electric physical fencing for cows. We recommend using manure as a noninvasive physiological measure of large grazer stress during virtual fencing to survey and understand animal welfare.

Abstract

To increase the efficiency and geographic expansion of nature conservation, large grazers have recently been used, either in the form of wild hoof-bearing animals or as domesticated ruminants including cattle. Using physical fencing limits migrating wildlife, while virtual fences encourage the animals to stay in the desired area without physical restrictions on wild animals. However, virtual fences raise ethical questions regarding the electric impulses emitted by the collar and stress in the fenced animals. Here, we tested if keeping twelve Angus cows (Bos Taurus) in a virtual fencing (Nofence©) compromised their welfare. For this purpose, we collected manure samples from five cows every second day prior to and after the transition from traditional to virtual fencing over a period of 18 days. Cortisol concentrations were 20.6 ± 5.23 ng/g w/w (mean ± SD), ranging from 12 to 42 ng/g w/w across individuals and concentrations did not change over the study period. We, therefore, conclude that there is no evidence suggesting that the cows were stressed from the use for virtual fencing, thus making virtual fencing a reasonable alternative to traditional electric physical fencing of cows.

Follicular fluid steroid hormones and in vitro embryo development in Duroc and Landrace pigs

The Duroc sire line has a smaller litter size compared to the Landrace dam line and we have previously observed fewer surface follicles on Duroc ovaries one day after weaning. In that same study, a broader cumulus expansion and faster nuclear maturation were observed for Duroc oocytes at 20 h of in vitro maturation (IVM), while Landrace oocytes showed more advanced stages of cortical granule distributions. However, no differences between breeds were observed after the final IVM period. The aim of this study was to assess subsequent in vitro embryo production (IVP) in Duroc and Landrace. Furthermore, follicle diameter and steroid hormone levels in follicular fluid (FF) were measured to study possible relation to oocyte developmental competence. Follicular phase sow ovaries were collected one day after weaning and follicle size of the 10 largest follicles were measured per ovary before aspiration. Cumulus-oocyte complexes (COCs) were matured in vitro, and cumulus expansion was analysed by assessing individual COC areas at 0 and 20 h. Fertilization of Duroc and Landrace oocytes was performed with sperm from both a Duroc and a Landrace boar. A larger follicle diameter was observed for Landrace animals (5.7 vs. 4.8 mm, P < 0.0001) and individual COC area was additionally larger at 0 h after aspiration (P < 0.0001) compared to Duroc. Contrary, cumulus expansion from 0 to 20 h of maturation was broader for Duroc oocytes than for Landrace (407 ± 67% vs. 319 ± 31%, P < 0.0001). After fertilization, cleavage rate was higher for Duroc oocytes, and the highest blastocyst yield was obtained for Duroc oocytes fertilized with the Landrace sperm. Steroid hormone analysis of the follicular fluid showed differences in the pathways between breeds with a higher total level of estrogens (P = 0.01) and aromatase products/substrates ratio (P < 0.01) in Landrace compared to Duroc. In conclusion, results suggest that Duroc oocytes have a better in vitro oocyte developmental competence when cultured under the same in vitro conditions and breed differences in steroidogenesis were found in the early follicular phase.

Metabolic Alteration Analysis of Steroid Hormones in Niemann-Pick Disease Type C Model Cell Using Liquid Chromatography/Tandem Mass Spectrometry

Niemann–Pick disease type C (NPC) is an autosomal recessive disease caused by a functional deficiency of cholesterol-transporting proteins in lysosomes, and exhibits various clinical symptoms. Since mitochondrial dysfunction in NPC has recently been reported, cholesterol catabolism to steroid hormones may consequently be impaired. In this study, we developed a comprehensive steroid hormone analysis method using liquid chromatography/tandem mass spectrometry (LC–MS/MS) and applied it to analyze changes in steroid hormone concentrations in NPC model cells. We investigated the analytical conditions for simultaneous LC–MS/MS analysis, which could be readily separated from each other and showed good reproducibility. The NPC phenotype was verified as an NPC model with mitochondrial abnormalities using filipin staining and organelle morphology observations. Steroid hormones in the cell suspension and cell culture medium were also analyzed. Steroid hormone analysis indicated that the levels of six steroid hormones were significantly decreased in the NPC model cell and culture medium compared to those in the wild-type cell and culture medium. These results indicate that some steroid hormones change during NPC pathophysiology and this change is accompanied by mitochondrial abnormalities.

Magnetic Micro-Solid-Phase Extraction Using a Novel Carbon-Based Composite Coupled with HPLC-MS/MS for Steroid Multiclass Determination in Human Plasma

A micron-sized sorbent, Magn-Humic, has been prepared by humic acids pyrolysis onto silica-coated magnetite. The material was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), and Brunauer, Emmett, and Teller (BET) surface area measurements and applied for simultaneous magnetic solid-phase extraction (MSPE) of glucocorticoids, estrogens, progestogens, and androgens at ng mL⁻¹ levels from human plasma followed by high-performance liquid chromatography coupled with mass spectrometry (HPLC–MS/MS). Due to the low affinity for proteins, steroids extraction was done with no need for proteins precipitation/centrifugation. As highlighted by a design of experiments, MSPE was performed on 250 µL plasma (after 1:4 dilution) by 50 mg Magn-Humic (reusable for eight extractions) achieving quantitative recovery and satisfying clean-up. This was improved by washing (2 mL 2% v/v formic acid) prior to analytes elution by 0.5 mL 1:1 v/v methanol-acetonitrile followed by 0.5 mL methanol; eluate reduction to 0.25 mL compensated the initial sample dilution. The accuracy was assessed in certified blank fetal bovine serum and in human plasma, gaining satisfactory recovery in the range 65–122%, detection limits in the range 0.02–0.3 ng mL⁻¹ (0.8 ng mL⁻¹ for 17-β-estradiol) and suitable inter-day precision (relative standard deviation (RSD) <14%, n = 3). The method was evaluated in terms of selectivity, sensitivity, matrix-effect, instrumental carry-over, and it was applied to human plasma samples.

A quantitative method for the selective 5-HT2A agonist 25CN-NBOH in rat plasma and brain

In recent years, agonists of the 5-HT_2A receptor have gained increasing attention for their potential therapeutic use to treat psychological disorders such as anxiety and depression. Here, we report the development and validation of an LC-MSMS based analytical method for the quantification of the novel selective 5-HT_2A agonist 25CN-NBOH in rat plasma and brain. As simple and efficient sample clean-up we applied the Phree Phospholipid Removal approach from Phenomenex, which is particularly novel for brain samples. In order to investigate the metabolic stability of 25CN-NBOH in vitro biotransformation studies with recombinant enzymes and human liver microsomes were conducted. Several biotransformation products and pathways could be identified. Based on the in vitro study one of the putative metabolites (2C-CN) was included in the analytical method development. To test the methods applicability 25CN-NBOH was quantified in plasma and brain samples from a pharmacokinetic in vivo study with Wildtype Long Evans rats. Both the in vitro metabolism data as well as the in vivo PK data suggest that 25CN-NBOH is susceptible to metabolism, but is degraded slower and is more stable compared to other NBOMe's investigated to date. The developed analytical method might serve as basis to include further 25CN-NBOH metabolites. It is expected to facilitate further preclinical and clinical investigations of 25CN-NBOH in biological matrices.

Is the unique benzodiazepine structure interacting with CYP enzymes to affect steroid synthesis in vitro?

The aim of this project was to investigate the endocrine disrupting effects of three γ-aminobutyric acid type A receptor (GABA_AR) agonists, diazepam (DZ), oxazepam (OX) and alprazolam (AL) using the steroidogenic in vitro H295R cell line assay, a recombinant CYP17A1 assay, qPCR analysis and computational modelling. Similar effects for DZ and OX on the steroidogenesis were observed in the H295R experiment at therapeutically relevant concentrations. Progestagens and corticosteroids were increased up to 10 fold and androgens were decreased indicating CYP17A1 lyase inhibition. For DZ the inhibition on both the hydroxylase and lyase was confirmed by the recombinant CYP17A1 assay, whereas OX did not appear to directly affect the recombinant CYP17A1 enzyme. Androgens were decreased when exposing the H295R cells to AL, indicating a CYP17A1 lyase inhibition. However, this was not confirmed by the recombinant CYP17A1 assay but a down-regulation in gene expression was observed for StAR and CYP17A1. The present study showed that the three investigated benzodiazepines (BZDs) are rather potent endocrine disruptors in vitro, exerting endocrine effects close the therapeutic C_max. Both direct and indirect effects on steroidogenesis were observed, but molecular modelling indicated no direct interactions between the heme group in the steroidogenic CYP enzymes and the unique diazepin structure. In contrast, physicochemical properties such as high log P, structure and molecular weight similar to that of steroids appeared to influence the endocrine disrupting abilities of the investigated pharmaceuticals in vitro. Docking of the three BZDs in CYP17A1 and CYP21A2 confirmed that shape complementarity and hydrophobic effects seem to determine the binding modes.

Microcystins and Microcystis aeruginosa PCC7806 extracts modulate steroidogenesis differentially in the human H295R adrenal model

The aim of this study was to investigate the potential interference of cyanobacterial metabolites, in particular microcystins (MCs), with steroid hormone biosynthesis. Steroid hormones control many fundamental processes in an organism, thus alteration of their tissue concentrations may affect normal homeostasis. We used liquid chromatography–tandem mass spectrometry (LC–MS/MS) to investigate the modulation of 14 hormones involved in the adrenal steroid biosynthesis pathway using forskolin-treated H295R cells, following exposure with either microcystin-LR (MC-LR) alone, a mixture made up of MC-LR together with eight other MCs and nodularin-R (NOD-R), or extracts from the MC-LR-producing Microcystis aeruginosa PCC7806 strain or its MC-deficient mutant PCC7806mcyB−. Production of 17-hydroxypregnenolone and dehydroepiandrosterone (DHEA) was increased in the presence of MC-LR in a dose-dependent manner, indicating an inhibitory effect on 3β-hydroxysteroid dehydrogenase (3β-HSD). This effect was not observed following exposure with a MCs/NOD-R mixture, and thus the effect of MC-LR on 3β-HSD appears to be stronger than for other congeners. Exposure to extracts from both M. aeruginosa PCC7806 and M. aeruginosa PCC7806mcyB− had an opposite effect on 3β-HSD, i.e. concentrations of pregnenolone, 17-hydroxypregnenolone and DHEA were significantly decreased, showing that there are other cyanobacterial metabolites that outcompete the effect of MC-LR, and possibly result instead in net-induction. Another finding was a possible concentration-dependent inhibition of CYP21A2 or CYP11β1, which catalyse oxidation reactions leading to cortisol and cortisone, by MC-LR and the MCs/NOD-R mixture. However, both M. aeruginosa PCC7806 and M. aeruginosa PCC7806mcyB− extracts had an opposite effect resulting in a substantial increase in cortisol levels. Our results suggest that MCs can modulate steroidogenesis, but the net effect of the M. aeruginosa metabolome on steroidogenesis is different from that of pure MC-LR and independent of MC production.

Oral anti-diabetic drugs as endocrine disruptors in vitro - No evidence for additive effects in binary mixtures

Diabetes is one of the World's most concerning health problems and millions of patients are using anti-diabetic drugs (ADDs) in order to control blood glucose. The in vitro H295R steroidogenesis assay was implemented to investigate endocrine effects of three ADDs, metformin (MET), glimepiride (GLIM), sitagliptin (SIT) and the cholesterol-lowering drug simvastatin (SIM) individually and in three binary mixtures. Steroid hormones were analyzed using LC-MS/MS. Mixture effects were assessed by applying the Concentration Addition (CA) model. All tested drugs and binary mixtures interrupted the H295R steroidogenesis with different potency. The effects of MET:GLIM on the steroidogenesis were overall similar to the steroidogenic profile of GLIM, however effects were less pronounced. The binary mixture of MET:SIT showed overall minor effects on steroid production and only at very high concentrations. The SIM:SIT mixture showed inhibition downstream from cholesterol, which was attributed to the effects of SIM. The CA model partly predicted the effect of MET:SIT on some steroids but significantly overestimated the effects of MET:GLIM and SIM:SIT. Thus, the applicability of the CA model was limited and cocktail effects appeared to be intermediate responses of individual drugs, rather than additive. The complexity of dynamic pathways such as steroidogenesis appears to significantly reduce the use of the CA model. In conclusion, more dynamic models are needed to predict mixture effects in complex systems.

HA-C@silica sorbent for simultaneous extraction and clean-up of steroids in human plasma followed by HPLC-MS/MS multiclass determination

Aim and novelty of this work are the development of a simple and straightforward analytical procedure for multiclass determination of steroid hormones in human plasma. The method entails a single pre-treatment step based on solid-phase extraction using a recently proposed sorbent phase (HA-C@silica). This is easily prepared with good reproducibility via pyrolysis of humic acids onto silica, and not yet tested in biological fluids. It proved to be advantageous as it showed poor affinity for the protein matrix constituents while quantitatively extracting and pre-concentrating the target analytes. Indeed, as demonstrated in bovine serum albumin solution, up to ca. 90% protein is not retained by the sorbent, similarly to the behaviour of restricted access carbon nanotubes, tested for comparison. The high albumin exclusion allowed a satisfactory clean-up avoiding protein precipitation and centrifugation before extraction. The extraction procedure, optimized by a chemometric approach (2³ experimental design) in BSA solution, provided quantitative recovery (76-119%, n = 3) for all steroids working with 1:8-diluted plasma (2 mL) and 100 mg HA-C@silica. Before analytes elution by 1 mL methanol-acetonitrile (1:1, v/v), selective washings (2% v/v formic acid and 30% v/v methanol) were applied to remove the small fraction of retained proteins, thus obtaining very clean SPE extracts to be analyzed by HPLC-ESI-MS/MS. This allowed identification/quantification (MRM mode) at few ng mL^-1 by a single chromatographic run. The procedure was verified in blank-certified foetal bovine serum (spikes 10-100 ng mL^-1), obtaining good recovery and suitable inter-day precision (RSDs < 15%, n = 3). The analytical method, applied to real plasma samples analysis, is appealing in terms of sample throughput, extraction efficiency and clean-up.

Measuring and validating concentrations of steroid hormones in the skin of bottlenose dolphins (Tursiops truncatus)

A previously published analytical method demonstrated the quantification of the hormone cortisol in cetacean skin. However, little is known about the transfer of hormones between blood and skin. Recognizing that such information is essential to effectively using skin samples within marine mammal stress research, the primary goals of this study were to (i) expand on the number of steroid hormones proved quantifiable in the cetacean skin matrix and (ii) validate the use of cetacean skin as a matrix for measuring stress-related hormones. Five adult bottlenose dolphins were subjected to an out of water stress test. Non-invasive sloughed skin samples were collected from each dolphin: once ~3 and once ~1 week prior to the stress test; at the time of the stress test; and twice weekly for 11 to 17 weeks subsequent to the stress test. LCMS/MS analysis of the samples recovered consistent data on three corticosteroids (cortisol, aldosterone, corticosterone), two androgens (testosterone, DHEA) and one progestagen (progesterone). A range of other hormones were also quantifiable, although not consistently so across samples. Results demonstrated that the hormonal response to an acute stressor could be detected in skin: the time from stress test to skin cortisol peak was an average of 46 days, whereas it was 55 days for corticosterone and 47 days for aldosterone. Results also showed that baseline hormonal concentrations were obtainable from skin samples collected during or immediately after the animals were subjected to the acute stressor. This study further develops and validates a non-invasive method for measuring cortisol and other hormones related to stress, health, and reproduction in the skin of cetaceans, potentially supporting investigations of acute and chronic stress, such as cetacean endocrine responses to distinct (e.g. naval sonar exposure) or prolonged stressors (e.g. shipping noise).

The anti-epileptic drug lamotrigine inhibits the CYP17A1 lyase reaction in vitro

The potential endocrine disrupting effects of the commonly prescribed anti-epileptic drug lamotrigine (LAM) were investigated using the H295R steroidogenic in vitro assay and computational chemistry methods. The H295R cells were exposed to different concentrations of LAM, and a multi-steroid LC-MS/MS method was applied to quantify the amount of secreted steroid hormones. LAM affected several steroid hormones in the steroidogenesis at therapeutic concentrations. All progestagens as well as 11-deoxycorticosterone and corticosterone increased 100-200% with increasing concentrations of LAM suggesting a selective inhibitory effect of LAM on CYP17A1, in particular on the lyase reaction. Recombinant CYP17A1 assay confirmed the competitive inhibition of LAM toward the enzyme with IC50 values of 619 and 764 μM for the lyase and the hydroxylase reaction, respectively. Levels of androstenedione and testosterone decreased at LAM concentrations above the therapeutic concentration range. The ability of LAM to bind to CYP17A1, CYP19A1, and CYP21A2 was investigated using docking and molecular dynamics simulations. This in silico study showed that LAM was able to bind directly to the heme iron in the active site of CYP17A1, but not CYP21A2, thus supporting the results of the in vitro studies. The molecular dynamics simulations also suggested binding of LAM to the heme iron in the CYP19A1 active site. No inhibition of the aromatase enzyme was, however, observed in the H295R assay. This could be due to a sequential effect within the steroidogenesis caused by the inhibition of CYP17A1, which reduced the amounts of androgens available for CYP19A1.

Effects of defined mixtures of POPs and endocrine disruptors on the steroid metabolome of the human H295R adrenocortical cell line

The presence of environmental pollutants in our ecosystem may impose harmful health effects to wildlife and humans. Several of these toxic chemicals have a potential to interfere with the endocrine system. The adrenal cortex has been identified as the main target organ affected by endocrine disrupting chemicals. The aim of this work was to assess exposure effects of defined and environmentally relevant mixtures of chlorinated, brominated and perfluorinated chemicals on steroidogenesis, using the H295R adrenocortical cell line model in combination with a newly developed liquid chromatography tandem mass spectrometry (LC-MS/MS) method. By using this approach, we could simultaneously analyze 19 of the steroids in the steroid biosynthesis pathway, revealing a deeper insight into possible disruption of steroidogenesis. Our results showed a noticeable down-regulation in steroid production when cells were exposed to the highest concentration of a mixture of brominated and fluorinated compounds (10,000-times human blood values). In contrast, up-regulation was observed with estrone under the same experimental condition, as well as with some other steroids when cells were exposed to a perfluorinated mixture (1000-times human blood values), and the mixture of chlorinated and fluorinated compounds. Interestingly, the low concentration of the perfluorinated mixture alone produced a significant, albeit small, down-regulation of pregnenolone, and the total mixture a similar effect on 17-hydroxypregnenolone. Other mixtures resulted in only slight deviations from the control. Indication of synergistic effects were noted when we used a statistical model to improve data interpretation. A potential for adverse outcomes of human exposures is indicated, pointing to the need for further investigation into these mixtures.

A sensitive and robust UPLC-MS/MS method for quantitation of estrogens and progestogens in human serum

OBJECTIVE

With the widespread use of sex-steroid hormones in contraceptives and hormone replacement therapy, there is an increasing need for reliable analytical methods. We report the development of a sensitive and robust UPLC-MS/MS method for quantitation of both endogenous and synthetic sex-steroid hormones in human serum.

STUDY DESIGN

We developed and validated a UPLC-MS/MS method to quantify progestogens (etonogestrel, levonorgestrel, medroxyprogesterone acetate, norethindrone, progesterone) and estrogens (estradiol and ethinyl estradiol) with good accuracy, high sensitivity, and excellent robustness. We then applied the method to the analysis of sex-steroid hormones in serum from 451 clinical research participants.

RESULTS

Each UPLC-MS/MS analysis was 6.5 min. The lower limits of quantitation (LLOQs) were 25 pg/ml for the progestogens, and 2.5 and 5.0 pg/ml for estradiol and ethinyl estradiol, respectively. When estradiol was analyzed without assessment of progestogens, the LLOQ was reduced to 1 pg/ml. The calibration curves were linear from 25-50,000, 2.5-2000 (1-2000 for estrogens-only analysis) and 5-2000 pg/ml, respectively. Both the accuracy and precision were below±15% not only for routine validation (intraday and interday), but for long-term (>2 years) assay robustness with external controls, thereby, demonstrating the utility of this method for multi-year clinical trial assessments of progestogens and estrogens. We applied the method to quantify sex-steroid levels in 1804 clinical samples.

CONCLUSIONS

We successfully developed a UPLC-MS/MS method, and overcame the matrix suppression to allow sensitive quantitation of both synthetic and endogenous sex-steroid hormones in human serum.

IMPLICATIONS

We developed a sensitive and robust UPLC-MS/MS method to accurately measure the levels of sex-steroid hormones in serum. The method overcame matrix interference barriers and achieved excellent long-term stability and reproducibility (≥96.9% accuracy; ≤13.0% relative variability measured with external controls over 2 years), demonstrating its utility in clinical sample analysis.

Occurrence, removal and risk assessment of steroid hormones in two wastewater stabilization pond systems in Morogoro, Tanzania

The present study investigated the occurrence and removal of 10 steroid hormones (4 androgens, 3 progestagens and 3 estrogens) in two WSP systems, Mafisa and Mzumbe in Morogoro, Tanzania. All 10 steroid hormones were detected in the influent of both WSP systems in the dry as well as in the rainy season. The concentrations of steroids in influent wastewater ranged from 0.1 ng/L for 17-OH-pregnenolone to 445 ng/L for estrone and from below limit of detection for 17-OH-pregnenolone to 45 ng/L for estrone in effluent. During dry season, the overall mean ± standard deviation removal efficiency for the 10 steroids were 70 ± 21% for Mzumbe WSP and 97 ± 3% for Mafisa WSP. During the rainy season the overall mean removal efficiency for all the steroid hormones were 52 ± 32% for Mzumbe WSP and 94 ± 8% for Mafisa WSP. Risk was characterized by calculating the risk quotients (RQs) for fish and humans. 46% of the total RQs calculated were above one, indicating high risk. Low RQs were estimated for androgens and progestagens but the estrogen concentrations measured in the WSP systems and Morogoro River indicated a high risk for fish. However, estrogens appeared not to pose an appreciable risk to human health from water intake and fish consumption. The results indicated that WSP systems are quite effective in removing steroid hormones from wastewater. Thus, low technology systems such as WSP systems are suitable techniques in low income counties due to relatively low costs of building, operating and maintaining these systems.

LC-MS/MS based profiling and dynamic modelling of the steroidogenesis pathway in adrenocarcinoma H295R cells

Endocrine disrupting chemicals have been reported to exert effects directly on enzymes involved in steroid biosynthesis. Here, we present a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for profiling the steroid metabolome of H295R human adrenocarcinoma cells. Our method can simultaneously analyse 19 precursors, intermediates and end-products, representing the adrenal steroid biosynthesis pathway. In order to obtain better insights into the processes of steroidogenesis, we investigated the dose-response relationship of forskolin, an activator of adenylate cyclase, on steroid production in H295R cells. We observed that 1.5 μM forskolin stimulated steroid production at approximately 50% of the maximum rate for most steroids. Hence, we studied the time course for steroid synthesis over 72 h in H295R cells that were stimulated with forskolin. At 24 h, we observed a peak in steroid levels for the intermediate metabolites, such as progesterone and pregnenolone, while end-products such as testosterone and cortisol continued to increase until 72 h. Finally, we show how global data provide a unique basis to develop a comprehensive, dynamic model for steroidogenesis using first order kinetics. The timeline data made it possible to estimate all reaction rate constants of the network. We propose this method as a unique and sensitive screening tool to identify effects on adrenal steroidogenesis by endocrine disrupting compounds.

Effects of antihistamines on the H295R steroidogenesis - Autocrine up-regulation following 3β-HSD inhibition

Millions of people of all ages suffer from allergies worldwide and as a consequence antihistamines are among the most commonly prescribed pharmaceuticals in the world. We investigated the disruptive effects of three antihistamines, promethazine (PMZ), cetirizine (CET) and fexofenadine (FEX) on the H295R steroidogenesis. A multi-steroid LC-MS/MS method was used to quantify 13 steroid hormones in the steroidogenesis. In addition, real-time RT-PCR was used to determine if exposure to antihistamines altered gene expression in the cell line. When exposing the H295R cells to PMZ and CET, significant increases in Δ⁵-steroids and significant decreases in Δ⁴-steroids were observed, indicating an inhibition of 3β-hydroxysteroid dehydrogenase (3β-HSD). A sequential decrease in corticosteroids, androgens and estrogens were also observed. Overall, FEX had no effect on the steroidogenesis even though minor effects were observed at the highest concentrations. Real-time RT-PCR showed that PMZ resulted in significant up-regulation of 3β-HSD and 17β-HSD, whereas CET only resulted in up-regulation of 3β-HSD. This indicated that the decrease in steroids downstream from 3β-HSD following PMZ and CT exposure induced a compensatory autocrine response in 3β-HSD gene expression. The effects on the steroidogenesis were observed at concentrations 30-50 times higher than the therapeutic plasma concentrations. However, antihistamines are lipophilic and may accumulate in adrenals and gonads. Thus, disruptive effects of PMZ and CET on human steroidogenesis cannot be excluded.

Testosterone and Corticosterone in the Mesocorticolimbic System of Male Rats: Effects of Gonadectomy and Caloric Restriction

Steroid hormones can modulate motivated behaviors through the mesocorticolimbic system. Gonadectomy (GDX) is a common method to determine how steroids influence the mesocorticolimbic system, and caloric restriction (CR) is often used to invigorate motivated behaviors. A common assumption is that the effects of these manipulations on brain steroid levels reflects circulating steroid levels. We now know that the brain regulates local steroid levels in a region-specific manner; however, previous studies have low spatial resolution. Using ultrasensitive liquid chromatography tandem mass spectrometry, we examined steroids in microdissected regions of the mesocorticolimbic system (ventral tegmental area, nucleus accumbens, medial prefrontal cortex). We examined whether GDX or CR influences systemic and local steroids, particularly testosterone (T) and steroidogenic enzyme transcripts. Adult male rats underwent a GDX surgery and/or CR for either 2 or 6 weeks. Levels of T, the primary steroid of interest, were higher in all brain regions than in the blood, whereas corticosterone (CORT) was lower in the brain than in the blood. Importantly, GDX completely eliminated T in the blood and lowered T in the brain. Yet, T remained present in the brain, even 6 weeks after GDX. CR decreased both T and CORT in the blood and brain. Steroidogenic enzyme (Cyp17a1, 3β-hydroxysteroid dehydrogenase, aromatase) transcripts and androgen receptor transcripts were expressed in the mesocorticolimbic system and differentially affected by GDX and CR. Together, these results suggest that T is synthesized within the mesocorticolimbic system. These results provide a foundation for future studies examining how neurosteroids influence behaviors mediated by the mesocorticolimbic system.

Development and validation of an ultra-high performance liquid chromatographic high resolution Q-Orbitrap mass spectrometric method for the simultaneous determination of steroidal endocrine disrupting compounds in aquatic matrices

The lack of adequate strategies for monitoring endocrine disrupting compounds (EDCs) in the aquatic environment is emphasized in the European Water Framework Directive. In this context, a new UHPLC-HR-Q-Orbirtrap-MS multi-residue method was developed for the simultaneous measurement of 70 steroidal EDCs in two aquatic matrices, i.e. sea and fresh water. First, an instrumental APCI-UHPLC-HR-Q-Orbitrap-MS was devised for separating and detecting the EDC isomers and mass analogues, within 12.5 min per run. Next, an appropriate extraction was statistically optimised using a three-strep workflow (95% confidence interval, p > 0.05); including fractional factorial resolution IV, simplex lattice, and response surface methodological designs. The fitness-for-purpose of the method was demonstrated through successful validation at relevant environmental concentrations, i.e. the low nano- and picogram range. Method quantification limits ranged for the androgens (n = 33), oestrogens (n = 14), progestins (n = 12), and corticosteroids (n = 11) between, respectively, 0.13 and 5.00 ng L^-1, 0.25 and 5.00 ng L^-1, 0.13 and 2.50 ng L^-1, and 0.50 and 5.00 ng L^-1. Good linearity (R² ≥ 0.99) and no lack of fit was observed (95% confidence interval, p > 0.05) for the 70 steroidal EDCs. In addition, good recovery (95-109%) and satisfactory repeatability (RSD < 8.5%, n = 18) and reproducibility (RSD < 10.5%, n = 12) were obtained. Finally, the applicability of the multi-residue method was demonstrated by measuring steroidal EDC in 28 sea water samples collected from four different locations during fall 2016 and winter 2017. Regarding the sea water samples, all the classes were ubiquitously present and included different metabolites, transformation product and or degradation products from the parent EDCs (n = 43).

A UHPLC-MS/MS method for profiling multifunctional steroids in human hair

It is important to profile steroids in many physiological and pathological processes. Recently, hair has been used for the long-term measurement of endogenous steroid hormones. Analyzing hair has advantages of being noninvasive and time sequential compared with other bio-specimens. Liquid chromatography-mass spectrometry (LC-MS) techniques have been widely used over the past decades; however, it is challenging to profile estrogens in hair by LC-MS, and more comprehensive steroid profiling is required. In this paper, an ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to simultaneously profile 28 multifunctional steroids, including corticosteroids (n = 6), estrogens (n = 13), androgens (n = 5) and progestogens (n = 4), in human scalp hair in a single run. To optimize the sample preparation procedure, we evaluated extraction time, post-incubation purification and hair fragment length; 30 mg hair samples were washed with hexane, cut into 5 mm pieces and incubated in methanol for 18 h at 25 °C. Methanol extraction derivatized using Girard P and dansyl chloride reagent was analyzed within 25 min using an automated injection program combined with a diverter valve switch and step analysis (AIDSA). The method was well validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, matrix effect and recovery, and was successfully applied to a steroid profile from male and female hairs. Significant differences were observed between genders. In addition, steroids showed a declining trend from the proximal to more distal hair segments; thus, care should be taken when obtaining hair samples for analysis to account for this difference in steroid levels along the length of hair. Graphical Abstract The workflow of the estabished UHPLC-MS/MS method.

Structure-based optimisation of non-steroidal cytochrome P450 17A1 inhibitors

Five new non-steroidal inhibitors for cytochrome P450 17A1 were identified by structure-based optimisation.

Promising Tools in Prostate Cancer Research: Selective Non-Steroidal Cytochrome P450 17A1 Inhibitors

Cytochrome P450 17A1 (CYP17A1) is an important target in the treatment of prostate cancer because it produces androgens required for tumour growth. The FDA has approved only one CYP17A1 inhibitor, abiraterone, which contains a steroidal scaffold similar to the endogenous CYP17A1 substrates. Abiraterone is structurally similar to the substrates of other cytochrome P450 enzymes involved in steroidogenesis, and interference can pose a liability in terms of side effects. Using non-steroidal scaffolds is expected to enable the design of compounds that interact more selectively with CYP17A1. Therefore, we combined a structure-based virtual screening approach with density functional theory (DFT) calculations to suggest non-steroidal compounds selective for CYP17A1. In vitro assays demonstrated that two such compounds selectively inhibited CYP17A1 17α-hydroxylase and 17,20-lyase activities with IC50 values in the nanomolar range, without affinity for the major drug-metabolizing CYP2D6 and CYP3A4 enzymes and CYP21A2, with the latter result confirmed in human H295R cells.